From 75130439b86c35ff4b9b91d9994b24a2110e8061 Mon Sep 17 00:00:00 2001
From: Stephen Gutekanst <stephen.gutekanst@gmail.com>
Date: Sat, 9 Dec 2017 22:31:59 -0700
Subject: [PATCH] add new data-driven test suite + move all existing tests to
 it (#178)

* testsuite: add new data-driven test suite implementation

* move TestAddStylesheet to new test suite

* move TestSetTitle to new test suite

* move TestRenderBody_Nested to new test suite

* move TestRenderBody_Standard_loading to new test suite

* move TestRenderBody_Standard_loaded to new test suite

* move TestRenderBody_ExpectsBody to new test suite

* move TestRenderBody_RenderSkipper_Skip into new test suite

* move TestRerender_Nested to new test suite

* move TestRerender_Nested to new test suite

* move TestRerender_identical to new test suite

* move TestRerender_no_prevRender to new test suite

* move TestHTML_reconcile_nil to new test suite

* move TestHTML_reconcile_std to new test suite

* testsuite: remove now unused sortedMapString function

* testsuite: remove now unused mockObject type
---
 .gitignore                                    |    1 +
 dom_test.go                                   | 1934 +++--------------
 testdata/TestAddStylesheet.want.txt           |    7 +
 ...reconcile_nil__add_event_listener.want.txt |    7 +
 ...estHTML_reconcile_nil__attributes.want.txt |    7 +
 .../TestHTML_reconcile_nil__children.want.txt |   17 +
 ...econcile_nil__children_render_nil.want.txt |   17 +
 ...TML_reconcile_nil__create_element.want.txt |    5 +
 ..._reconcile_nil__create_element_ns.want.txt |    5 +
 ...L_reconcile_nil__create_text_node.want.txt |    5 +
 .../TestHTML_reconcile_nil__dataset.want.txt  |    7 +
 ...estHTML_reconcile_nil__inner_html.want.txt |    6 +
 ...estHTML_reconcile_nil__properties.want.txt |    7 +
 .../TestHTML_reconcile_nil__style.want.txt    |    7 +
 ...L_reconcile_std__attributes__diff.want.txt |   16 +
 ...reconcile_std__attributes__remove.want.txt |   16 +
 ...tHTML_reconcile_std__class__combo.want.txt |   18 +
 ...stHTML_reconcile_std__class__diff.want.txt |   16 +
 ...estHTML_reconcile_std__class__map.want.txt |   15 +
 ..._reconcile_std__class__map_toggle.want.txt |   15 +
 ...tHTML_reconcile_std__class__multi.want.txt |   16 +
 ...HTML_reconcile_std__class__remove.want.txt |   15 +
 ...HTML_reconcile_std__dataset__diff.want.txt |   16 +
 ...ML_reconcile_std__dataset__remove.want.txt |   16 +
 ...econcile_std__event_listener_diff.want.txt |   18 +
 ...L_reconcile_std__properties__diff.want.txt |   16 +
 ...reconcile_std__properties__remove.want.txt |   16 +
 ...d__properties__replaced_elem_diff.want.txt |   15 +
 ..._properties__replaced_elem_shared.want.txt |   15 +
 ...stHTML_reconcile_std__style__diff.want.txt |   16 +
 ...HTML_reconcile_std__style__remove.want.txt |   16 +
 ...TestHTML_reconcile_std__text_diff.want.txt |    6 +
 ...TML_reconcile_std__text_identical.want.txt |    5 +
 .../TestRenderBody_ExpectsBody__div.want.txt  |    6 +
 .../TestRenderBody_ExpectsBody__nil.want.txt  |    6 +
 .../TestRenderBody_ExpectsBody__text.want.txt |    6 +
 testdata/TestRenderBody_Nested.want.txt       |    9 +
 ...TestRenderBody_RenderSkipper_Skip.want.txt |    1 +
 .../TestRenderBody_Standard_loaded.want.txt   |    9 +
 .../TestRenderBody_Standard_loading.want.txt  |   11 +
 ...erender_Nested__component_to_html.want.txt |   23 +
 ...erender_Nested__html_to_component.want.txt |   23 +
 .../TestRerender_Nested__new_child.want.txt   |   23 +
 .../TestRerender_change__new_child.want.txt   |   23 +
 testdata/TestRerender_identical.want.txt      |   16 +
 testdata/TestRerender_no_prevRender.want.txt  |    0
 testdata/TestSetTitle.want.txt                |    2 +
 testsuite_test.go                             |  277 +++
 48 files changed, 1081 insertions(+), 1668 deletions(-)
 create mode 100755 testdata/TestAddStylesheet.want.txt
 create mode 100755 testdata/TestHTML_reconcile_nil__add_event_listener.want.txt
 create mode 100755 testdata/TestHTML_reconcile_nil__attributes.want.txt
 create mode 100755 testdata/TestHTML_reconcile_nil__children.want.txt
 create mode 100755 testdata/TestHTML_reconcile_nil__children_render_nil.want.txt
 create mode 100755 testdata/TestHTML_reconcile_nil__create_element.want.txt
 create mode 100755 testdata/TestHTML_reconcile_nil__create_element_ns.want.txt
 create mode 100755 testdata/TestHTML_reconcile_nil__create_text_node.want.txt
 create mode 100755 testdata/TestHTML_reconcile_nil__dataset.want.txt
 create mode 100755 testdata/TestHTML_reconcile_nil__inner_html.want.txt
 create mode 100755 testdata/TestHTML_reconcile_nil__properties.want.txt
 create mode 100755 testdata/TestHTML_reconcile_nil__style.want.txt
 create mode 100755 testdata/TestHTML_reconcile_std__attributes__diff.want.txt
 create mode 100755 testdata/TestHTML_reconcile_std__attributes__remove.want.txt
 create mode 100755 testdata/TestHTML_reconcile_std__class__combo.want.txt
 create mode 100755 testdata/TestHTML_reconcile_std__class__diff.want.txt
 create mode 100755 testdata/TestHTML_reconcile_std__class__map.want.txt
 create mode 100755 testdata/TestHTML_reconcile_std__class__map_toggle.want.txt
 create mode 100755 testdata/TestHTML_reconcile_std__class__multi.want.txt
 create mode 100755 testdata/TestHTML_reconcile_std__class__remove.want.txt
 create mode 100755 testdata/TestHTML_reconcile_std__dataset__diff.want.txt
 create mode 100755 testdata/TestHTML_reconcile_std__dataset__remove.want.txt
 create mode 100755 testdata/TestHTML_reconcile_std__event_listener_diff.want.txt
 create mode 100755 testdata/TestHTML_reconcile_std__properties__diff.want.txt
 create mode 100755 testdata/TestHTML_reconcile_std__properties__remove.want.txt
 create mode 100755 testdata/TestHTML_reconcile_std__properties__replaced_elem_diff.want.txt
 create mode 100755 testdata/TestHTML_reconcile_std__properties__replaced_elem_shared.want.txt
 create mode 100755 testdata/TestHTML_reconcile_std__style__diff.want.txt
 create mode 100755 testdata/TestHTML_reconcile_std__style__remove.want.txt
 create mode 100755 testdata/TestHTML_reconcile_std__text_diff.want.txt
 create mode 100755 testdata/TestHTML_reconcile_std__text_identical.want.txt
 create mode 100755 testdata/TestRenderBody_ExpectsBody__div.want.txt
 create mode 100755 testdata/TestRenderBody_ExpectsBody__nil.want.txt
 create mode 100755 testdata/TestRenderBody_ExpectsBody__text.want.txt
 create mode 100755 testdata/TestRenderBody_Nested.want.txt
 create mode 100755 testdata/TestRenderBody_RenderSkipper_Skip.want.txt
 create mode 100755 testdata/TestRenderBody_Standard_loaded.want.txt
 create mode 100755 testdata/TestRenderBody_Standard_loading.want.txt
 create mode 100755 testdata/TestRerender_Nested__component_to_html.want.txt
 create mode 100755 testdata/TestRerender_Nested__html_to_component.want.txt
 create mode 100755 testdata/TestRerender_Nested__new_child.want.txt
 create mode 100755 testdata/TestRerender_change__new_child.want.txt
 create mode 100755 testdata/TestRerender_identical.want.txt
 create mode 100644 testdata/TestRerender_no_prevRender.want.txt
 create mode 100755 testdata/TestSetTitle.want.txt
 create mode 100644 testsuite_test.go

diff --git a/.gitignore b/.gitignore
index 63123fbe..94e5c618 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,2 @@
+testdata/*.got.txt
 .DS_store
diff --git a/dom_test.go b/dom_test.go
index 1473bc38..a8682001 100644
--- a/dom_test.go
+++ b/dom_test.go
@@ -2,18 +2,11 @@ package vecty
 
 import (
 	"fmt"
-	"sort"
-	"strings"
 	"testing"
 
 	"github.com/gopherjs/gopherjs/js"
 )
 
-var _ = func() bool {
-	isTest = true
-	return true
-}()
-
 type testCore struct{ Core }
 
 func (testCore) Render() ComponentOrHTML { return Tag("p") }
@@ -99,572 +92,246 @@ func TestHTML_Node(t *testing.T) {
 // works as expected (i.e. that it updates nodes correctly).
 func TestHTML_reconcile_std(t *testing.T) {
 	t.Run("text_identical", func(t *testing.T) {
-		h := Text("foobar")
-		hNode := &mockObject{}
-		h.node = hNode
-		prev := Text("foobar")
-		prevNode := &mockObject{}
-		prev.node = prevNode
-		h.reconcile(prev)
-		if h.node != prevNode {
-			t.Fatal("h.node != prevNode")
-		}
+		ts := testSuite(t, "TestHTML_reconcile_std__text_identical")
+		defer ts.done()
+
+		init := Text("foobar")
+		init.reconcile(nil)
+
+		target := Text("foobar")
+		target.reconcile(init)
 	})
 	t.Run("text_diff", func(t *testing.T) {
-		want := "bar"
-		h := Text(want)
-		hNode := &mockObject{}
-		h.node = hNode
-		prev := Text("foo")
-		setNodeValue := ""
-		prevNode := &mockObject{
-			set: func(key string, value interface{}) {
-				if key != "nodeValue" {
-					panic(`key != "nodeValue"`)
-				}
-				setNodeValue = value.(string)
-			},
-		}
-		prev.node = prevNode
-		h.reconcile(prev)
-		if h.node != prevNode {
-			t.Fatal("h.node != prevNode")
-		}
-		if setNodeValue != want {
-			t.Fatalf("got %q want %q", setNodeValue, want)
-		}
+		ts := testSuite(t, "TestHTML_reconcile_std__text_diff")
+		defer ts.done()
+
+		init := Text("bar")
+		init.reconcile(nil)
+
+		target := Text("foo")
+		target.reconcile(init)
 	})
 	t.Run("properties", func(t *testing.T) {
 		cases := []struct {
-			name         string
-			initHTML     *HTML
-			initResult   string
-			targetHTML   *HTML
-			targetResult string
+			name        string
+			initHTML    *HTML
+			targetHTML  *HTML
+			sortedLines [][2]int
 		}{
 			{
-				name:         "diff",
-				initHTML:     Tag("div", Markup(Property("a", 1), Property("b", "2foobar"))),
-				initResult:   "a:1 b:2foobar",
-				targetHTML:   Tag("div", Markup(Property("a", 3), Property("b", "4foobar"))),
-				targetResult: "a:3 b:4foobar",
+				name:        "diff",
+				initHTML:    Tag("div", Markup(Property("a", 1), Property("b", "2foobar"))),
+				targetHTML:  Tag("div", Markup(Property("a", 3), Property("b", "4foobar"))),
+				sortedLines: [][2]int{{3, 4}, {12, 13}},
 			},
 			{
-				name:         "remove",
-				initHTML:     Tag("div", Markup(Property("a", 1), Property("b", "2foobar"))),
-				initResult:   "a:1 b:2foobar",
-				targetHTML:   Tag("div", Markup(Property("a", 3))),
-				targetResult: "a:3",
+				name:        "remove",
+				initHTML:    Tag("div", Markup(Property("a", 1), Property("b", "2foobar"))),
+				targetHTML:  Tag("div", Markup(Property("a", 3))),
+				sortedLines: [][2]int{{3, 4}},
 			},
 			{
-				name:         "replaced_elem_diff",
-				initHTML:     Tag("div", Markup(Property("a", 1), Property("b", "2foobar"))),
-				initResult:   "a:1 b:2foobar",
-				targetHTML:   Tag("span", Markup(Property("a", 3), Property("b", "4foobar"))),
-				targetResult: "a:3 b:4foobar",
+				name:        "replaced_elem_diff",
+				initHTML:    Tag("div", Markup(Property("a", 1), Property("b", "2foobar"))),
+				targetHTML:  Tag("span", Markup(Property("a", 3), Property("b", "4foobar"))),
+				sortedLines: [][2]int{{3, 4}, {11, 12}},
 			},
 			{
-				name:         "replaced_elem_shared",
-				initHTML:     Tag("div", Markup(Property("a", 1), Property("b", "2foobar"))),
-				initResult:   "a:1 b:2foobar",
-				targetHTML:   Tag("span", Markup(Property("a", 1), Property("b", "4foobar"))),
-				targetResult: "a:1 b:4foobar",
+				name:        "replaced_elem_shared",
+				initHTML:    Tag("div", Markup(Property("a", 1), Property("b", "2foobar"))),
+				targetHTML:  Tag("span", Markup(Property("a", 1), Property("b", "4foobar"))),
+				sortedLines: [][2]int{{3, 4}, {11, 12}},
 			},
 		}
 		for _, tst := range cases {
 			t.Run(tst.name, func(t *testing.T) {
-				initSet := make(map[string]interface{})
-				targetSet := make(map[string]interface{})
-				initElem := &mockObject{
-					set: func(key string, value interface{}) {
-						initSet[key] = value
-					},
-					delete: func(key string) {
-						delete(initSet, key)
-					},
-				}
-				targetElem := &mockObject{
-					set: func(key string, value interface{}) {
-						targetSet[key] = value
-					},
-					delete: func(key string) {
-						delete(targetSet, key)
-					},
-				}
-				wrapperFunc := func(obj jsObject) func(string, ...interface{}) jsObject {
-					return func(name string, args ...interface{}) jsObject {
-						if name != "createElement" {
-							panic(fmt.Sprintf("expected call to createElement, not %q", name))
-						}
-						if len(args) != 1 {
-							panic("len(args) != 1")
-						}
-						if args[0].(string) != "div" && args[0].(string) != "span" {
-							panic(`args[0].(string) != "div|span"`)
-						}
-						return obj
-					}
-				}
-				global = &mockObject{
-					get: map[string]jsObject{
-						"document": &mockObject{call: wrapperFunc(initElem)},
-					},
-				}
+				ts := testSuite(t, "TestHTML_reconcile_std__properties__"+tst.name)
+				defer ts.multiSortedDone(tst.sortedLines...)
+
 				tst.initHTML.reconcile(nil)
-				got := sortedMapString(initSet)
-				if got != tst.initResult {
-					t.Fatalf("got %q want %q", got, tst.initResult)
-				}
-				matchingTags := tst.initHTML.tag == tst.targetHTML.tag
-				if !matchingTags {
-					global = &mockObject{
-						get: map[string]jsObject{
-							"document": &mockObject{call: wrapperFunc(targetElem)},
-						},
-					}
-				}
+				ts.record("(first reconcile done)")
 				tst.targetHTML.reconcile(tst.initHTML)
-				if matchingTags {
-					got = sortedMapString(initSet)
-				} else {
-					got = sortedMapString(targetSet)
-				}
-				if got != tst.targetResult {
-					t.Fatalf("got %q want %q", got, tst.targetResult)
-				}
 			})
 		}
 	})
 	t.Run("attributes", func(t *testing.T) {
 		cases := []struct {
-			name         string
-			initHTML     *HTML
-			initResult   string
-			targetHTML   *HTML
-			targetResult string
+			name        string
+			initHTML    *HTML
+			targetHTML  *HTML
+			sortedLines [][2]int
 		}{
 			{
-				name:         "diff",
-				initHTML:     Tag("div", Markup(Attribute("a", 1), Attribute("b", "2foobar"))),
-				initResult:   "a:1 b:2foobar",
-				targetHTML:   Tag("div", Markup(Attribute("a", 3), Attribute("b", "4foobar"))),
-				targetResult: "a:3 b:4foobar",
+				name:        "diff",
+				initHTML:    Tag("div", Markup(Attribute("a", 1), Attribute("b", "2foobar"))),
+				targetHTML:  Tag("div", Markup(Attribute("a", 3), Attribute("b", "4foobar"))),
+				sortedLines: [][2]int{{3, 4}, {12, 13}},
 			},
 			{
-				name:         "remove",
-				initHTML:     Tag("div", Markup(Attribute("a", 1), Attribute("b", "2foobar"))),
-				initResult:   "a:1 b:2foobar",
-				targetHTML:   Tag("div", Markup(Attribute("a", 3))),
-				targetResult: "a:3",
+				name:        "remove",
+				initHTML:    Tag("div", Markup(Attribute("a", 1), Attribute("b", "2foobar"))),
+				targetHTML:  Tag("div", Markup(Attribute("a", 3))),
+				sortedLines: [][2]int{{3, 4}},
 			},
 		}
 		for _, tst := range cases {
 			t.Run(tst.name, func(t *testing.T) {
-				set := map[string]interface{}{}
-				div := &mockObject{
-					call: func(name string, args ...interface{}) jsObject {
-						switch name {
-						case "setAttribute":
-							if len(args) != 2 {
-								panic("setAttribute: len(args) != 2")
-							}
-							set[args[0].(string)] = args[1]
-						case "removeAttribute":
-							if len(args) != 1 {
-								panic("removeAttribute: len(args) != 1")
-							}
-							delete(set, args[0].(string))
-						default:
-							panic(fmt.Sprintf("expected call to [setAttribute, removeAttribute], not %q", name))
-						}
-						return nil
-					},
-				}
-				document := &mockObject{
-					call: func(name string, args ...interface{}) jsObject {
-						if name != "createElement" {
-							panic(fmt.Sprintf("expected call to createElement, not %q", name))
-						}
-						if len(args) != 1 {
-							panic("len(args) != 1")
-						}
-						if args[0].(string) != "div" {
-							panic(`args[0].(string) != "div"`)
-						}
-						return div
-					},
-				}
-				global = &mockObject{
-					get: map[string]jsObject{
-						"document": document,
-					},
-				}
+				ts := testSuite(t, "TestHTML_reconcile_std__attributes__"+tst.name)
+				defer ts.multiSortedDone(tst.sortedLines...)
+
 				tst.initHTML.reconcile(nil)
-				got := sortedMapString(set)
-				if got != tst.initResult {
-					t.Fatalf("got %q want %q", got, tst.initResult)
-				}
+				ts.record("(first reconcile done)")
 				tst.targetHTML.reconcile(tst.initHTML)
-				got = sortedMapString(set)
-				if got != tst.targetResult {
-					t.Fatalf("got %q want %q", got, tst.targetResult)
-				}
 			})
 		}
 	})
 	t.Run("class", func(t *testing.T) {
 		cases := []struct {
-			name         string
-			initHTML     *HTML
-			initResult   string
-			targetHTML   *HTML
-			targetResult string
+			name        string
+			initHTML    *HTML
+			targetHTML  *HTML
+			sortedLines [][2]int
 		}{
 			{
-				name:         "multi",
-				initHTML:     Tag("div", Markup(Class("a"), Class("b"))),
-				initResult:   "a:true b:true",
-				targetHTML:   Tag("div", Markup(Class("a"), Class("c"))),
-				targetResult: "a:true c:true",
+				name:        "multi",
+				initHTML:    Tag("div", Markup(Class("a"), Class("b"))),
+				targetHTML:  Tag("div", Markup(Class("a"), Class("c"))),
+				sortedLines: [][2]int{{4, 5}},
 			},
 			{
-				name:         "diff",
-				initHTML:     Tag("div", Markup(Class("a", "b"))),
-				initResult:   "a:true b:true",
-				targetHTML:   Tag("div", Markup(Class("a", "c"))),
-				targetResult: "a:true c:true",
+				name:        "diff",
+				initHTML:    Tag("div", Markup(Class("a", "b"))),
+				targetHTML:  Tag("div", Markup(Class("a", "c"))),
+				sortedLines: [][2]int{{4, 5}},
 			},
 			{
-				name:         "remove",
-				initHTML:     Tag("div", Markup(Class("a", "b"))),
-				initResult:   "a:true b:true",
-				targetHTML:   Tag("div", Markup(Class("a"))),
-				targetResult: "a:true",
+				name:        "remove",
+				initHTML:    Tag("div", Markup(Class("a", "b"))),
+				targetHTML:  Tag("div", Markup(Class("a"))),
+				sortedLines: [][2]int{{4, 5}},
 			},
 			{
-				name:         "map",
-				initHTML:     Tag("div", Markup(ClassMap{"a": true, "b": true})),
-				initResult:   "a:true b:true",
-				targetHTML:   Tag("div", Markup(ClassMap{"a": true})),
-				targetResult: "a:true",
+				name:        "map",
+				initHTML:    Tag("div", Markup(ClassMap{"a": true, "b": true})),
+				targetHTML:  Tag("div", Markup(ClassMap{"a": true})),
+				sortedLines: [][2]int{{4, 5}},
 			},
 			{
-				name:         "map_toggle",
-				initHTML:     Tag("div", Markup(ClassMap{"a": true, "b": true})),
-				initResult:   "a:true b:true",
-				targetHTML:   Tag("div", Markup(ClassMap{"a": true, "b": false})),
-				targetResult: "a:true",
+				name:        "map_toggle",
+				initHTML:    Tag("div", Markup(ClassMap{"a": true, "b": true})),
+				targetHTML:  Tag("div", Markup(ClassMap{"a": true, "b": false})),
+				sortedLines: [][2]int{{4, 5}},
 			},
 			{
-				name:         "combo",
-				initHTML:     Tag("div", Markup(ClassMap{"a": true, "b": true}, Class("c"))),
-				initResult:   "a:true b:true c:true",
-				targetHTML:   Tag("div", Markup(ClassMap{"a": true, "b": false}, Class("d"))),
-				targetResult: "a:true d:true",
+				name:        "combo",
+				initHTML:    Tag("div", Markup(ClassMap{"a": true, "b": true}, Class("c"))),
+				targetHTML:  Tag("div", Markup(ClassMap{"a": true, "b": false}, Class("d"))),
+				sortedLines: [][2]int{{4, 6}, {11, 12}},
 			},
 		}
 		for _, tst := range cases {
 			t.Run(tst.name, func(t *testing.T) {
-				set := map[string]interface{}{}
-				classList := &mockObject{
-					call: func(name string, args ...interface{}) jsObject {
-						if len(args) != 1 {
-							panic("len(args) != 1")
-						}
-						if _, ok := args[0].(string); !ok {
-							panic("args[0].(string) is not string")
-						}
-						switch name {
-						case "add":
-							set[args[0].(string)] = true
-						case "remove":
-							delete(set, args[0].(string))
-						default:
-							panic(fmt.Sprintf("expected call to add|remove, not %q", name))
-						}
-						return nil
-					},
-				}
-				div := &mockObject{
-					get: map[string]jsObject{
-						"classList": classList,
-					},
-				}
-				document := &mockObject{
-					call: func(name string, args ...interface{}) jsObject {
-						if name != "createElement" {
-							panic(fmt.Sprintf("expected call to createElement, not %q", name))
-						}
-						if len(args) != 1 {
-							panic("len(args) != 1")
-						}
-						if args[0].(string) != "div" {
-							panic(`args[0].(string) != "div"`)
-						}
-						return div
-					},
-				}
-				global = &mockObject{
-					get: map[string]jsObject{
-						"document": document,
-					},
-				}
+				ts := testSuite(t, "TestHTML_reconcile_std__class__"+tst.name)
+				defer ts.multiSortedDone(tst.sortedLines...)
+
 				tst.initHTML.reconcile(nil)
-				got := sortedMapString(set)
-				if got != tst.initResult {
-					t.Fatalf("got %q want %q", got, tst.initResult)
-				}
+				ts.record("(first reconcile done)")
 				tst.targetHTML.reconcile(tst.initHTML)
-				got = sortedMapString(set)
-				if got != tst.targetResult {
-					t.Fatalf("got %q want %q", got, tst.targetResult)
-				}
 			})
 		}
 	})
 	t.Run("dataset", func(t *testing.T) {
 		cases := []struct {
-			name         string
-			initHTML     *HTML
-			initResult   string
-			targetHTML   *HTML
-			targetResult string
+			name        string
+			initHTML    *HTML
+			targetHTML  *HTML
+			sortedLines [][2]int
 		}{
 			{
-				name:         "diff",
-				initHTML:     Tag("div", Markup(Data("a", "1"), Data("b", "2foobar"))),
-				initResult:   "a:1 b:2foobar",
-				targetHTML:   Tag("div", Markup(Data("a", "3"), Data("b", "4foobar"))),
-				targetResult: "a:3 b:4foobar",
+				name:        "diff",
+				initHTML:    Tag("div", Markup(Data("a", "1"), Data("b", "2foobar"))),
+				targetHTML:  Tag("div", Markup(Data("a", "3"), Data("b", "4foobar"))),
+				sortedLines: [][2]int{{5, 6}, {14, 15}},
 			},
 			{
-				name:         "remove",
-				initHTML:     Tag("div", Markup(Data("a", "1"), Data("b", "2foobar"))),
-				initResult:   "a:1 b:2foobar",
-				targetHTML:   Tag("div", Markup(Data("a", "3"))),
-				targetResult: "a:3",
+				name:        "remove",
+				initHTML:    Tag("div", Markup(Data("a", "1"), Data("b", "2foobar"))),
+				targetHTML:  Tag("div", Markup(Data("a", "3"))),
+				sortedLines: [][2]int{{5, 6}},
 			},
 		}
 		for _, tst := range cases {
 			t.Run(tst.name, func(t *testing.T) {
-				set := map[string]interface{}{}
-				dataset := &mockObject{
-					set: func(key string, value interface{}) {
-						set[key] = value
-					},
-					delete: func(key string) {
-						delete(set, key)
-					},
-				}
-				div := &mockObject{
-					get: map[string]jsObject{
-						"dataset": dataset,
-					},
-				}
-				document := &mockObject{
-					call: func(name string, args ...interface{}) jsObject {
-						if name != "createElement" {
-							panic(fmt.Sprintf("expected call to createElement, not %q", name))
-						}
-						if len(args) != 1 {
-							panic("len(args) != 1")
-						}
-						if args[0].(string) != "div" {
-							panic(`args[0].(string) != "div"`)
-						}
-						return div
-					},
-				}
-				global = &mockObject{
-					get: map[string]jsObject{
-						"document": document,
-					},
-				}
+				ts := testSuite(t, "TestHTML_reconcile_std__dataset__"+tst.name)
+				defer ts.multiSortedDone(tst.sortedLines...)
+
 				tst.initHTML.reconcile(nil)
-				got := sortedMapString(set)
-				if got != tst.initResult {
-					t.Fatalf("got %q want %q", got, tst.initResult)
-				}
+				ts.record("(first reconcile done)")
 				tst.targetHTML.reconcile(tst.initHTML)
-				got = sortedMapString(set)
-				if got != tst.targetResult {
-					t.Fatalf("got %q want %q", got, tst.targetResult)
-				}
 			})
 		}
 	})
 	t.Run("style", func(t *testing.T) {
 		cases := []struct {
-			name         string
-			initHTML     *HTML
-			initResult   string
-			targetHTML   *HTML
-			targetResult string
+			name        string
+			initHTML    *HTML
+			targetHTML  *HTML
+			sortedLines [][2]int
 		}{
 			{
-				name:         "diff",
-				initHTML:     Tag("div", Markup(Style("a", "1"), Style("b", "2foobar"))),
-				initResult:   "a:1 b:2foobar",
-				targetHTML:   Tag("div", Markup(Style("a", "3"), Style("b", "4foobar"))),
-				targetResult: "a:3 b:4foobar",
+				name:        "diff",
+				initHTML:    Tag("div", Markup(Style("a", "1"), Style("b", "2foobar"))),
+				targetHTML:  Tag("div", Markup(Style("a", "3"), Style("b", "4foobar"))),
+				sortedLines: [][2]int{{6, 7}, {15, 16}},
 			},
 			{
-				name:         "remove",
-				initHTML:     Tag("div", Markup(Style("a", "1"), Style("b", "2foobar"))),
-				initResult:   "a:1 b:2foobar",
-				targetHTML:   Tag("div", Markup(Style("a", "3"))),
-				targetResult: "a:3",
+				name:        "remove",
+				initHTML:    Tag("div", Markup(Style("a", "1"), Style("b", "2foobar"))),
+				targetHTML:  Tag("div", Markup(Style("a", "3"))),
+				sortedLines: [][2]int{{6, 7}},
 			},
 		}
 		for _, tst := range cases {
 			t.Run(tst.name, func(t *testing.T) {
-				set := map[string]interface{}{}
-				style := &mockObject{
-					call: func(name string, args ...interface{}) jsObject {
-						switch name {
-						case "setProperty":
-							if len(args) != 2 {
-								panic("setProperty: len(args) != 2")
-							}
-							set[args[0].(string)] = args[1]
-						case "removeProperty":
-							if len(args) != 1 {
-								panic("removeProperty: len(args) != 1")
-							}
-							delete(set, args[0].(string))
-						default:
-							panic(fmt.Sprintf("expected call to [setProperty, removeProperty], not %q", name))
-						}
-						return nil
-					},
-				}
-				div := &mockObject{
-					get: map[string]jsObject{
-						"style": style,
-					},
-				}
-				document := &mockObject{
-					call: func(name string, args ...interface{}) jsObject {
-						if name != "createElement" {
-							panic(fmt.Sprintf("expected call to createElement, not %q", name))
-						}
-						if len(args) != 1 {
-							panic("len(args) != 1")
-						}
-						if args[0].(string) != "div" {
-							panic(`args[0].(string) != "div"`)
-						}
-						return div
-					},
-				}
-				global = &mockObject{
-					get: map[string]jsObject{
-						"document": document,
-					},
-				}
+				ts := testSuite(t, "TestHTML_reconcile_std__style__"+tst.name)
+				defer ts.multiSortedDone(tst.sortedLines...)
+
 				tst.initHTML.reconcile(nil)
-				got := sortedMapString(set)
-				if got != tst.initResult {
-					t.Fatalf("got %q want %q", got, tst.initResult)
-				}
+				ts.record("(first reconcile done)")
 				tst.targetHTML.reconcile(tst.initHTML)
-				got = sortedMapString(set)
-				if got != tst.targetResult {
-					t.Fatalf("got %q want %q", got, tst.targetResult)
-				}
 			})
 		}
 	})
 	t.Run("event_listener", func(t *testing.T) {
 		// TODO(pdf): Mock listener functions for equality testing
-		cases := []struct {
-			name                 string
-			initEventListeners   []Applyer
-			targetEventListeners []Applyer
-		}{
-			{
-				name: "diff",
-				initEventListeners: []Applyer{
-					&EventListener{Name: "click"},
-					&EventListener{Name: "keydown"},
-				},
-				targetEventListeners: []Applyer{
-					&EventListener{Name: "click"},
-				},
-			},
+		ts := testSuite(t, "TestHTML_reconcile_std__event_listener_diff")
+		defer ts.done()
+
+		initEventListeners := []Applyer{
+			&EventListener{Name: "click"},
+			&EventListener{Name: "keydown"},
 		}
-		for _, tst := range cases {
-			t.Run(tst.name, func(t *testing.T) {
-				addedListeners := map[string]func(*js.Object){}
-				div := &mockObject{
-					call: func(name string, args ...interface{}) jsObject {
-						switch name {
-						case "addEventListener":
-							if len(args) != 2 {
-								panic("addEventListener: len(args) != 2")
-							}
-							addedListeners[args[0].(string)] = args[1].(func(*js.Object))
-						case "removeEventListener":
-							if len(args) != 2 {
-								panic("removeEventListener: len(args) != 2")
-							}
-							delete(addedListeners, args[0].(string))
-						default:
-							panic(fmt.Sprintf("unexpected call to %q", name))
-						}
-						return nil
-					},
-				}
-				document := &mockObject{
-					call: func(name string, args ...interface{}) jsObject {
-						switch name {
-						case "createElement":
-							if len(args) != 1 {
-								panic("len(args) != 1")
-							}
-							if args[0].(string) != "div" {
-								panic(`args[0].(string) != "div"`)
-							}
-							return div
-						default:
-							panic(fmt.Sprintf("unexpected call to %q", name))
-						}
-					},
-				}
-				global = &mockObject{
-					get: map[string]jsObject{
-						"document": document,
-					},
-				}
-				prev := Tag("div", Markup(tst.initEventListeners...))
-				prev.reconcile(nil)
-				for i, m := range tst.initEventListeners {
-					listener := m.(*EventListener)
-					if listener.wrapper == nil {
-						t.Fatalf("listener %d wrapper == nil: %+v", i, listener)
-					}
-					if _, ok := addedListeners[listener.Name]; !ok {
-						t.Fatalf("listener %d for %q not found: %+v", i, listener.Name, listener)
-					}
-				}
-				if len(tst.initEventListeners) != len(addedListeners) {
-					t.Fatalf("listener count mismatch: %d != %d", len(tst.initEventListeners), len(addedListeners))
-				}
-				h := Tag("div", Markup(tst.targetEventListeners...))
-				h.reconcile(prev)
-				for i, m := range tst.targetEventListeners {
-					listener := m.(*EventListener)
-					if listener.wrapper == nil {
-						t.Fatalf("listener %d wrapper == nil: %+v", i, listener)
-					}
-					if _, ok := addedListeners[listener.Name]; !ok {
-						t.Fatalf("listener %d for %q not found: %+v", i, listener.Name, listener)
-					}
-				}
-				if len(tst.targetEventListeners) != len(addedListeners) {
-					t.Fatalf("listener count mismatch: %d != %d", len(tst.targetEventListeners), len(addedListeners))
-				}
-			})
+		prev := Tag("div", Markup(initEventListeners...))
+		prev.reconcile(nil)
+		ts.record("(expected two added event listeners above)")
+		for i, m := range initEventListeners {
+			listener := m.(*EventListener)
+			if listener.wrapper == nil {
+				t.Fatalf("listener %d wrapper == nil: %+v", i, listener)
+			}
+		}
+
+		targetEventListeners := []Applyer{
+			&EventListener{Name: "click"},
+		}
+		h := Tag("div", Markup(targetEventListeners...))
+		h.reconcile(prev)
+		ts.record("(expected two removed, one added event listeners above)")
+		for i, m := range targetEventListeners {
+			listener := m.(*EventListener)
+			if listener.wrapper == nil {
+				t.Fatalf("listener %d wrapper == nil: %+v", i, listener)
+			}
 		}
 	})
 
@@ -696,325 +363,65 @@ func TestHTML_reconcile_nil(t *testing.T) {
 		}
 	})
 	t.Run("create_element", func(t *testing.T) {
-		strong := &mockObject{}
-		createdElement := ""
-		document := &mockObject{
-			call: func(name string, args ...interface{}) jsObject {
-				if name != "createElement" {
-					panic(fmt.Sprintf("expected call to createElement, not %q", name))
-				}
-				if len(args) != 1 {
-					panic("len(args) != 1")
-				}
-				createdElement = args[0].(string)
-				return strong
-			},
-		}
-		global = &mockObject{
-			get: map[string]jsObject{
-				"document": document,
-			},
-		}
-		want := "strong"
-		h := Tag(want)
+		ts := testSuite(t, "TestHTML_reconcile_nil__create_element")
+		defer ts.done()
+
+		h := Tag("strong")
 		h.reconcile(nil)
-		if createdElement != want {
-			t.Fatalf("createdElement %q want %q", createdElement, want)
-		}
 	})
 	t.Run("create_element_ns", func(t *testing.T) {
-		strong := &mockObject{}
-		createdNamespace := ""
-		createdElement := ""
-		document := &mockObject{
-			call: func(name string, args ...interface{}) jsObject {
-				if name != "createElementNS" {
-					panic(fmt.Sprintf("expected call to createElementNS, not %q", name))
-				}
-				if len(args) != 2 {
-					panic("len(args) != 2")
-				}
-				createdNamespace = args[0].(string)
-				createdElement = args[1].(string)
-				return strong
-			},
-		}
-		global = &mockObject{
-			get: map[string]jsObject{
-				"document": document,
-			},
-		}
-		wantTag := "strong"
-		wantNamespace := "foobar"
-		h := Tag(wantTag, Markup(Namespace(wantNamespace)))
+		ts := testSuite(t, "TestHTML_reconcile_nil__create_element_ns")
+		defer ts.done()
+
+		h := Tag("strong", Markup(Namespace("foobar")))
 		h.reconcile(nil)
-		if createdElement != wantTag {
-			t.Fatalf("createdElement %q want tag %q", createdElement, wantTag)
-		}
-		if createdNamespace != wantNamespace {
-			t.Fatalf("createdNamespace %q want namespace %q", createdElement, wantNamespace)
-		}
 	})
 	t.Run("create_text_node", func(t *testing.T) {
-		textNode := &mockObject{}
-		createdTextNode := ""
-		document := &mockObject{
-			call: func(name string, args ...interface{}) jsObject {
-				if name != "createTextNode" {
-					panic(fmt.Sprintf("expected call to createTextNode, not %q", name))
-				}
-				if len(args) != 1 {
-					panic("len(args) != 1")
-				}
-				createdTextNode = args[0].(string)
-				return textNode
-			},
-		}
-		global = &mockObject{
-			get: map[string]jsObject{
-				"document": document,
-			},
-		}
-		want := "hello"
-		h := &HTML{text: want}
+		ts := testSuite(t, "TestHTML_reconcile_nil__create_text_node")
+		defer ts.done()
+
+		h := Text("hello")
 		h.reconcile(nil)
-		if createdTextNode != want {
-			t.Fatalf("createdTextNode %q want %q", createdTextNode, want)
-		}
 	})
 	t.Run("inner_html", func(t *testing.T) {
-		setInnerHTML := ""
-		div := &mockObject{
-			set: func(key string, value interface{}) {
-				if key != "innerHTML" {
-					panic(fmt.Sprintf(`expected document.set "innerHTML", not %q`, key))
-				}
-				setInnerHTML = value.(string)
-			},
-		}
-		document := &mockObject{
-			call: func(name string, args ...interface{}) jsObject {
-				if name != "createElement" {
-					panic(fmt.Sprintf("expected call to createElement, not %q", name))
-				}
-				if len(args) != 1 {
-					panic("len(args) != 1")
-				}
-				if args[0].(string) != "div" {
-					panic(`args[0].(string) != "div"`)
-				}
-				return div
-			},
-		}
-		global = &mockObject{
-			get: map[string]jsObject{
-				"document": document,
-			},
-		}
-		want := "<p>hello</p>"
-		h := Tag("div", Markup(UnsafeHTML(want)))
+		ts := testSuite(t, "TestHTML_reconcile_nil__inner_html")
+		defer ts.done()
+
+		h := Tag("div", Markup(UnsafeHTML("<p>hello</p>")))
 		h.reconcile(nil)
-		if setInnerHTML != want {
-			t.Fatalf("setInnerHTML %q want %q", setInnerHTML, want)
-		}
 	})
 	t.Run("properties", func(t *testing.T) {
-		set := map[string]interface{}{}
-		div := &mockObject{
-			set: func(key string, value interface{}) {
-				set[key] = value
-			},
-		}
-		document := &mockObject{
-			call: func(name string, args ...interface{}) jsObject {
-				if name != "createElement" {
-					panic(fmt.Sprintf("expected call to createElement, not %q", name))
-				}
-				if len(args) != 1 {
-					panic("len(args) != 1")
-				}
-				if args[0].(string) != "div" {
-					panic(`args[0].(string) != "div"`)
-				}
-				return div
-			},
-		}
-		global = &mockObject{
-			get: map[string]jsObject{
-				"document": document,
-			},
-		}
+		ts := testSuite(t, "TestHTML_reconcile_nil__properties")
+		defer ts.sortedDone(3, 4)
+
 		h := Tag("div", Markup(Property("a", 1), Property("b", "2foobar")))
 		h.reconcile(nil)
-		got := sortedMapString(set)
-		want := "a:1 b:2foobar"
-		if got != want {
-			t.Fatalf("got %q want %q", got, want)
-		}
 	})
 	t.Run("attributes", func(t *testing.T) {
-		set := map[string]interface{}{}
-		div := &mockObject{
-			call: func(name string, args ...interface{}) jsObject {
-				if name != "setAttribute" {
-					panic(fmt.Sprintf("expected call to setAttribute, not %q", name))
-				}
-				if len(args) != 2 {
-					panic("len(args) != 2")
-				}
-				set[args[0].(string)] = args[1]
-				return nil
-			},
-		}
-		document := &mockObject{
-			call: func(name string, args ...interface{}) jsObject {
-				if name != "createElement" {
-					panic(fmt.Sprintf("expected call to createElement, not %q", name))
-				}
-				if len(args) != 1 {
-					panic("len(args) != 1")
-				}
-				if args[0].(string) != "div" {
-					panic(`args[0].(string) != "div"`)
-				}
-				return div
-			},
-		}
-		global = &mockObject{
-			get: map[string]jsObject{
-				"document": document,
-			},
-		}
+		ts := testSuite(t, "TestHTML_reconcile_nil__attributes")
+		defer ts.sortedDone(3, 4)
+
 		h := Tag("div", Markup(Attribute("a", 1), Attribute("b", "2foobar")))
 		h.reconcile(nil)
-		got := sortedMapString(set)
-		want := "a:1 b:2foobar"
-		if got != want {
-			t.Fatalf("got %q want %q", got, want)
-		}
 	})
 	t.Run("dataset", func(t *testing.T) {
-		set := map[string]interface{}{}
-		dataset := &mockObject{
-			set: func(key string, value interface{}) {
-				set[key] = value
-			},
-		}
-		div := &mockObject{
-			get: map[string]jsObject{
-				"dataset": dataset,
-			},
-		}
-		document := &mockObject{
-			call: func(name string, args ...interface{}) jsObject {
-				if name != "createElement" {
-					panic(fmt.Sprintf("expected call to createElement, not %q", name))
-				}
-				if len(args) != 1 {
-					panic("len(args) != 1")
-				}
-				if args[0].(string) != "div" {
-					panic(`args[0].(string) != "div"`)
-				}
-				return div
-			},
-		}
-		global = &mockObject{
-			get: map[string]jsObject{
-				"document": document,
-			},
-		}
+		ts := testSuite(t, "TestHTML_reconcile_nil__dataset")
+		defer ts.sortedDone(5, 6)
+
 		h := Tag("div", Markup(Data("a", "1"), Data("b", "2foobar")))
 		h.reconcile(nil)
-		got := sortedMapString(set)
-		want := "a:1 b:2foobar"
-		if got != want {
-			t.Fatalf("got %q want %q", got, want)
-		}
 	})
 	t.Run("style", func(t *testing.T) {
-		set := map[string]interface{}{}
-		style := &mockObject{
-			call: func(name string, args ...interface{}) jsObject {
-				if name != "setProperty" {
-					panic(fmt.Sprintf("expected call to setProperty, not %q", name))
-				}
-				if len(args) != 2 {
-					panic("len(args) != 2")
-				}
-				set[args[0].(string)] = args[1]
-				return nil
-			},
-		}
-		div := &mockObject{
-			get: map[string]jsObject{
-				"style": style,
-			},
-		}
-		document := &mockObject{
-			call: func(name string, args ...interface{}) jsObject {
-				if name != "createElement" {
-					panic(fmt.Sprintf("expected call to createElement, not %q", name))
-				}
-				if len(args) != 1 {
-					panic("len(args) != 1")
-				}
-				if args[0].(string) != "div" {
-					panic(`args[0].(string) != "div"`)
-				}
-				return div
-			},
-		}
-		global = &mockObject{
-			get: map[string]jsObject{
-				"document": document,
-			},
-		}
+		ts := testSuite(t, "TestHTML_reconcile_nil__style")
+		defer ts.sortedDone(6, 7)
+
 		h := Tag("div", Markup(Style("a", "1"), Style("b", "2foobar")))
 		h.reconcile(nil)
-		got := sortedMapString(set)
-		want := "a:1 b:2foobar"
-		if got != want {
-			t.Fatalf("got %q want %q", got, want)
-		}
 	})
 	t.Run("add_event_listener", func(t *testing.T) {
-		addedListeners := map[string]func(*js.Object){}
-		div := &mockObject{
-			call: func(name string, args ...interface{}) jsObject {
-				switch name {
-				case "addEventListener":
-					if len(args) != 2 {
-						panic("len(args) != 2")
-					}
-					addedListeners[args[0].(string)] = args[1].(func(*js.Object))
-					return nil
-				default:
-					panic(fmt.Sprintf("unexpected call to %q", name))
-				}
-			},
-		}
-		document := &mockObject{
-			call: func(name string, args ...interface{}) jsObject {
-				switch name {
-				case "createElement":
-					if len(args) != 1 {
-						panic("len(args) != 1")
-					}
-					if args[0].(string) != "div" {
-						panic(`args[0].(string) != "div"`)
-					}
-					return div
-				default:
-					panic(fmt.Sprintf("unexpected call to %q", name))
-				}
-			},
-		}
-		global = &mockObject{
-			get: map[string]jsObject{
-				"document": document,
-			},
-		}
+		ts := testSuite(t, "TestHTML_reconcile_nil__add_event_listener")
+		defer ts.done()
+
 		e0 := &EventListener{Name: "click"}
 		e1 := &EventListener{Name: "keydown"}
 		h := Tag("div", Markup(e0, e1))
@@ -1025,56 +432,12 @@ func TestHTML_reconcile_nil(t *testing.T) {
 		if e1.wrapper == nil {
 			t.Fatal("e1.wrapper == nil")
 		}
-		if gotE0 := addedListeners["click"]; gotE0 == nil {
-			t.Fatal("gotE0 == nil")
-		}
-		if gotE1 := addedListeners["keydown"]; gotE1 == nil {
-			t.Fatal("gotE1 == nil")
-		}
 	})
 	t.Run("children", func(t *testing.T) {
-		var (
-			divs    []jsObject
-			appends = map[jsObject]jsObject{}
-		)
-		document := &mockObject{
-			call: func(name string, args ...interface{}) jsObject {
-				switch name {
-				case "createElement":
-					if len(args) != 1 {
-						panic("len(args) != 1")
-					}
-					if args[0].(string) != "div" {
-						panic(`args[0].(string) != "div"`)
-					}
-					div := &mockObject{}
-					divs = append(divs, div)
-					div.call = func(name string, args ...interface{}) jsObject {
-						switch name {
-						case "appendChild":
-							if len(args) != 1 {
-								panic("len(args) != 1")
-							}
-							appends[div] = args[0].(jsObject)
-							return nil
-						default:
-							panic(fmt.Sprintf("unexpected call to %q", name))
-						}
-					}
-					return div
-				default:
-					panic(fmt.Sprintf("unexpected call to %q", name))
-				}
-			},
-		}
-		global = &mockObject{
-			get: map[string]jsObject{
-				"document": document,
-			},
-		}
-		var (
-			compRenderCalls int
-		)
+		ts := testSuite(t, "TestHTML_reconcile_nil__children")
+		defer ts.done()
+
+		var compRenderCalls int
 		compRender := Tag("div")
 		comp := &componentFunc{
 			id: "foobar",
@@ -1085,9 +448,6 @@ func TestHTML_reconcile_nil(t *testing.T) {
 		}
 		h := Tag("div", Tag("div", comp))
 		h.reconcile(nil)
-		if len(divs) != 3 {
-			t.Fatal("len(divs) != 3")
-		}
 		if compRenderCalls != 1 {
 			t.Fatal("compRenderCalls != 1")
 		}
@@ -1097,59 +457,12 @@ func TestHTML_reconcile_nil(t *testing.T) {
 		if comp.Context().prevRender != compRender {
 			t.Fatal("comp.Context().prevRender != compRender")
 		}
-		root := divs[0]
-		child := divs[1]
-		child2 := divs[2]
-		if appends[root] != child {
-			t.Fatal("appends[root] != child")
-		}
-		if appends[child] != child2 {
-			t.Fatal("appends[root] != child2")
-		}
 	})
 	t.Run("children_render_nil", func(t *testing.T) {
-		var (
-			nodes   []jsObject
-			appends = map[jsObject]jsObject{}
-		)
-		document := &mockObject{
-			call: func(name string, args ...interface{}) jsObject {
-				switch name {
-				case "createElement":
-					if len(args) != 1 {
-						panic("len(args) != 1")
-					}
-					if n := args[0].(string); n != "div" && n != "noscript" {
-						panic(`n != "div" && n != "noscript"`)
-					}
-					n := &mockObject{}
-					nodes = append(nodes, n)
-					n.call = func(name string, args ...interface{}) jsObject {
-						switch name {
-						case "appendChild":
-							if len(args) != 1 {
-								panic("len(args) != 1")
-							}
-							appends[n] = args[0].(jsObject)
-							return nil
-						default:
-							panic(fmt.Sprintf("unexpected call to %q", name))
-						}
-					}
-					return n
-				default:
-					panic(fmt.Sprintf("unexpected call to %q", name))
-				}
-			},
-		}
-		global = &mockObject{
-			get: map[string]jsObject{
-				"document": document,
-			},
-		}
-		var (
-			compRenderCalls int
-		)
+		ts := testSuite(t, "TestHTML_reconcile_nil__children_render_nil")
+		defer ts.done()
+
+		var compRenderCalls int
 		comp := &componentFunc{
 			id: "foobar",
 			render: func() ComponentOrHTML {
@@ -1159,9 +472,6 @@ func TestHTML_reconcile_nil(t *testing.T) {
 		}
 		h := Tag("div", Tag("div", comp))
 		h.reconcile(nil)
-		if len(nodes) != 3 {
-			t.Fatal("len(nodes) != 3")
-		}
 		if compRenderCalls != 1 {
 			t.Fatal("compRenderCalls != 1")
 		}
@@ -1171,15 +481,6 @@ func TestHTML_reconcile_nil(t *testing.T) {
 		if comp.Context().prevRender == nil {
 			t.Fatal("comp.Context().prevRender == nil")
 		}
-		root := nodes[0]
-		child := nodes[1]
-		child2 := nodes[2]
-		if appends[root] != child {
-			t.Fatal("appends[root] != child")
-		}
-		if appends[child] != child2 {
-			t.Fatal("appends[root] != child2")
-		}
 	})
 }
 
@@ -1239,35 +540,9 @@ func TestRerender_nil(t *testing.T) {
 // TestRerender_no_prevRender tests the behavior of Rerender when there is no
 // previous render.
 func TestRerender_no_prevRender(t *testing.T) {
-	var renderCallback func(float64)
-	global = &mockObject{
-		get: map[string]jsObject{
-			"performance": &mockObject{
-				call: func(name string, args ...interface{}) jsObject {
-					if name != "now" {
-						panic(fmt.Sprintf("expected call to now, not %q", name))
-					}
-					if len(args) != 0 {
-						panic("len(args) != 0")
-					}
-					return &mockObject{floatValue: 0}
-				},
-			},
-		},
-		call: func(name string, args ...interface{}) jsObject {
-			if name != "requestAnimationFrame" {
-				panic(fmt.Sprintf("expected call to requestAnimationFrame, not %q", name))
-			}
-			if len(args) != 1 {
-				panic("len(args) != 1")
-			}
-			var ok bool
-			if renderCallback, ok = args[0].(func(float64)); !ok {
-				panic("incorrect argument to requestAnimationFrame")
-			}
-			return &mockObject{intValue: 0}
-		},
-	}
+	ts := testSuite(t, "TestRerender_no_prevRender")
+	defer ts.done()
+
 	got := recoverStr(func() {
 		Rerender(&componentFunc{
 			render: func() ComponentOrHTML {
@@ -1277,7 +552,6 @@ func TestRerender_no_prevRender(t *testing.T) {
 				panic("expected no SkipRender call")
 			},
 		})
-		renderCallback(0)
 	})
 	want := "vecty: Rerender invoked on Component that has never been rendered"
 	if got != want {
@@ -1288,66 +562,13 @@ func TestRerender_no_prevRender(t *testing.T) {
 // TestRerender_identical tests the behavior of Rerender when there is a
 // previous render which is identical to the new render.
 func TestRerender_identical(t *testing.T) {
-	// Perform the initial render of the component.
-	body := &mockObject{}
-	bodySet := false
-	document := &mockObject{
-		call: func(name string, args ...interface{}) jsObject {
-			if name != "createElement" {
-				panic(fmt.Sprintf("expected call to createElement, not %q", name))
-			}
-			if len(args) != 1 {
-				panic("len(args) != 1")
-			}
-			if args[0].(string) != "body" {
-				panic(`args[0].(string) != "body"`)
-			}
-			return body
-		},
-		get: map[string]jsObject{
-			"readyState": &mockObject{stringValue: "complete"},
-		},
-		set: func(key string, value interface{}) {
-			if key != "body" {
-				panic(fmt.Sprintf(`expected document.set "body", not %q`, key))
-			}
-			if value != body {
-				panic(fmt.Sprintf(`expected document.set body value, not %T %+v`, value, value))
-			}
-			bodySet = true
-		},
-	}
-	var renderCallback func(float64)
-	global = &mockObject{
-		get: map[string]jsObject{
-			"document": document,
-			"performance": &mockObject{
-				call: func(name string, args ...interface{}) jsObject {
-					if name != "now" {
-						panic(fmt.Sprintf("expected call to now, not %q", name))
-					}
-					if len(args) != 0 {
-						panic("len(args) != 0")
-					}
-					return &mockObject{floatValue: 0}
-				},
-			},
-		},
-		call: func(name string, args ...interface{}) jsObject {
-			if name != "requestAnimationFrame" {
-				panic(fmt.Sprintf("expected call to requestAnimationFrame, not %q", name))
-			}
-			if len(args) != 1 {
-				panic("len(args) != 1")
-			}
-			var ok bool
-			if renderCallback, ok = args[0].(func(float64)); !ok {
-				panic("incorrect argument to requestAnimationFrame")
-			}
-			return &mockObject{intValue: 0}
-		},
-	}
+	ts := testSuite(t, "TestRerender_identical")
+	defer ts.done()
 
+	ts.ints.mock(`global.Call("requestAnimationFrame", func(float64))`, 0)
+	ts.strings.mock(`global.Get("document").Get("readyState")`, "complete")
+
+	// Perform the initial render of the component.
 	render := Tag("body")
 	var renderCalled, skipRenderCalled int
 	comp := &componentFunc{
@@ -1358,9 +579,6 @@ func TestRerender_identical(t *testing.T) {
 		},
 	}
 	RenderBody(comp)
-	if !bodySet {
-		t.Fatal("!bodySet")
-	}
 	if renderCalled != 1 {
 		t.Fatal("renderCalled != 1")
 	}
@@ -1392,8 +610,11 @@ func TestRerender_identical(t *testing.T) {
 		return false
 	}
 	Rerender(comp)
-	renderCallback(0)
-	global = nil // Expecting no JS calls past here
+
+	// Invoke the render callback.
+	ts.ints.mock(`global.Call("requestAnimationFrame", func(float64))`, 0)
+	ts.callbacks[`global.Call("requestAnimationFrame", func(float64))`].(func(float64))(0)
+
 	if renderCalled != 2 {
 		t.Fatal("renderCalled != 2")
 	}
@@ -1428,80 +649,13 @@ func TestRerender_change(t *testing.T) {
 	}
 	for _, tst := range cases {
 		t.Run(tst.name, func(t *testing.T) {
-			// Perform the initial render of the component.
-			var bodyAppendChild jsObject
-			body := &mockObject{
-				call: func(name string, args ...interface{}) jsObject {
-					switch name {
-					case "appendChild":
-						if len(args) != 1 {
-							panic("len(args) != 1")
-						}
-						bodyAppendChild = args[0].(jsObject)
-						return nil
-					default:
-						panic(fmt.Sprintf("unexpected call to %q", name))
-					}
-				},
-			}
-			bodySet := false
-			document := &mockObject{
-				call: func(name string, args ...interface{}) jsObject {
-					if name != "createElement" {
-						panic(fmt.Sprintf("expected call to createElement, not %q", name))
-					}
-					if len(args) != 1 {
-						panic("len(args) != 1")
-					}
-					if args[0].(string) != "body" {
-						panic(`args[0].(string) != "body"`)
-					}
-					return body
-				},
-				get: map[string]jsObject{
-					"readyState": &mockObject{stringValue: "complete"},
-				},
-				set: func(key string, value interface{}) {
-					if key != "body" {
-						panic(fmt.Sprintf(`expected document.set "body", not %q`, key))
-					}
-					if value != body {
-						panic(fmt.Sprintf(`expected document.set body value, not %T %+v`, value, value))
-					}
-					bodySet = true
-				},
-			}
-			var renderCallback func(float64)
-			global = &mockObject{
-				get: map[string]jsObject{
-					"document": document,
-					"performance": &mockObject{
-						call: func(name string, args ...interface{}) jsObject {
-							if name != "now" {
-								panic(fmt.Sprintf("expected call to now, not %q", name))
-							}
-							if len(args) != 0 {
-								panic("len(args) != 0")
-							}
-							return &mockObject{floatValue: 0}
-						},
-					},
-				},
-				call: func(name string, args ...interface{}) jsObject {
-					if name != "requestAnimationFrame" {
-						panic(fmt.Sprintf("expected call to requestAnimationFrame, not %q", name))
-					}
-					if len(args) != 1 {
-						panic("len(args) != 1")
-					}
-					var ok bool
-					if renderCallback, ok = args[0].(func(float64)); !ok {
-						panic("incorrect argument to requestAnimationFrame")
-					}
-					return &mockObject{intValue: 0}
-				},
-			}
+			ts := testSuite(t, "TestRerender_change__"+tst.name)
+			defer ts.done()
 
+			ts.ints.mock(`global.Call("requestAnimationFrame", func(float64))`, 0)
+			ts.strings.mock(`global.Get("document").Get("readyState")`, "complete")
+
+			// Perform the initial render of the component.
 			render := Tag("body")
 			var renderCalled, skipRenderCalled int
 			comp := &componentFunc{
@@ -1512,9 +666,7 @@ func TestRerender_change(t *testing.T) {
 				},
 			}
 			RenderBody(comp)
-			if !bodySet {
-				t.Fatal("!bodySet")
-			}
+			ts.record("(expect body to be set now)")
 			if renderCalled != 1 {
 				t.Fatal("renderCalled != 1")
 			}
@@ -1526,58 +678,6 @@ func TestRerender_change(t *testing.T) {
 			}
 
 			// Perform a re-render.
-			body = &mockObject{}
-			newNode := &mockObject{}
-			document = &mockObject{
-				call: func(name string, args ...interface{}) jsObject {
-					switch name {
-					case "createElement":
-						if len(args) != 1 {
-							panic("len(args) != 1")
-						}
-						switch args[0].(string) {
-						case "body":
-							return body
-						case "div", "noscript":
-							return newNode
-						default:
-							panic("unexpected createElement call")
-						}
-					default:
-						panic(fmt.Sprintf("unexpected call to %q", name))
-					}
-				},
-			}
-			global = &mockObject{
-				get: map[string]jsObject{
-					"document": document,
-					"performance": &mockObject{
-						call: func(name string, args ...interface{}) jsObject {
-							if name != "now" {
-								panic(fmt.Sprintf("expected call to now, not %q", name))
-							}
-							if len(args) != 0 {
-								panic("len(args) != 0")
-							}
-							return &mockObject{floatValue: 0}
-						},
-					},
-				},
-				call: func(name string, args ...interface{}) jsObject {
-					if name != "requestAnimationFrame" {
-						panic(fmt.Sprintf("expected call to requestAnimationFrame, not %q", name))
-					}
-					if len(args) != 1 {
-						panic("len(args) != 1")
-					}
-					var ok bool
-					if renderCallback, ok = args[0].(func(float64)); !ok {
-						panic("incorrect argument to requestAnimationFrame")
-					}
-					return &mockObject{intValue: 0}
-				},
-			}
-
 			comp.id = "modified"
 			comp.render = func() ComponentOrHTML {
 				renderCalled++
@@ -1597,7 +697,11 @@ func TestRerender_change(t *testing.T) {
 				return false
 			}
 			Rerender(comp)
-			renderCallback(0)
+
+			// Invoke the render callback.
+			ts.ints.mock(`global.Call("requestAnimationFrame", func(float64))`, 0)
+			ts.callbacks[`global.Call("requestAnimationFrame", func(float64))`].(func(float64))(0)
+
 			if renderCalled != 2 {
 				t.Fatal("renderCalled != 2")
 			}
@@ -1610,9 +714,6 @@ func TestRerender_change(t *testing.T) {
 			if comp.Context().prevRenderComponent.(*componentFunc).id != "modified" {
 				t.Fatal(`comp.Context().prevRenderComponent.(*componentFunc).id != "modified"`)
 			}
-			if bodyAppendChild != newNode {
-				t.Fatal("bodyAppendChild != newNode")
-			}
 		})
 	}
 }
@@ -1651,80 +752,13 @@ func TestRerender_Nested(t *testing.T) {
 	}
 	for _, tst := range cases {
 		t.Run(tst.name, func(t *testing.T) {
-			// Perform the initial render of the component.
-			var bodyAppendChild jsObject
-			body := &mockObject{
-				call: func(name string, args ...interface{}) jsObject {
-					switch name {
-					case "appendChild":
-						if len(args) != 1 {
-							panic("len(args) != 1")
-						}
-						bodyAppendChild = args[0].(jsObject)
-						return nil
-					default:
-						panic(fmt.Sprintf("unexpected call to %q", name))
-					}
-				},
-			}
-			bodySet := false
-			document := &mockObject{
-				call: func(name string, args ...interface{}) jsObject {
-					if name != "createElement" {
-						panic(fmt.Sprintf("expected call to createElement, not %q", name))
-					}
-					if len(args) != 1 {
-						panic("len(args) != 1")
-					}
-					if args[0].(string) != "body" {
-						panic(`args[0].(string) != "body"`)
-					}
-					return body
-				},
-				get: map[string]jsObject{
-					"readyState": &mockObject{stringValue: "complete"},
-				},
-				set: func(key string, value interface{}) {
-					if key != "body" {
-						panic(fmt.Sprintf(`expected document.set "body", not %q`, key))
-					}
-					if value != body {
-						panic(fmt.Sprintf(`expected document.set body value, not %T %+v`, value, value))
-					}
-					bodySet = true
-				},
-			}
-			var renderCallback func(float64)
-			global = &mockObject{
-				get: map[string]jsObject{
-					"document": document,
-					"performance": &mockObject{
-						call: func(name string, args ...interface{}) jsObject {
-							if name != "now" {
-								panic(fmt.Sprintf("expected call to now, not %q", name))
-							}
-							if len(args) != 0 {
-								panic("len(args) != 0")
-							}
-							return &mockObject{floatValue: 0}
-						},
-					},
-				},
-				call: func(name string, args ...interface{}) jsObject {
-					if name != "requestAnimationFrame" {
-						panic(fmt.Sprintf("expected call to requestAnimationFrame, not %q", name))
-					}
-					if len(args) != 1 {
-						panic("len(args) != 1")
-					}
-					var ok bool
-					if renderCallback, ok = args[0].(func(float64)); !ok {
-						panic("incorrect argument to requestAnimationFrame")
-					}
-					return &mockObject{intValue: 0}
-				},
-			}
+			ts := testSuite(t, "TestRerender_Nested__"+tst.name)
+			defer ts.done()
 
+			ts.ints.mock(`global.Call("requestAnimationFrame", func(float64))`, 0)
+			ts.strings.mock(`global.Get("document").Get("readyState")`, "complete")
+
+			// Perform the initial render of the component.
 			var renderCalled, skipRenderCalled int
 			comp := &componentFunc{
 				id: "original",
@@ -1734,9 +768,7 @@ func TestRerender_Nested(t *testing.T) {
 				},
 			}
 			RenderBody(comp)
-			if !bodySet {
-				t.Fatal("!bodySet")
-			}
+			ts.record("(expect body to be set now)")
 			if renderCalled != 1 {
 				t.Fatal("renderCalled != 1")
 			}
@@ -1748,58 +780,6 @@ func TestRerender_Nested(t *testing.T) {
 			}
 
 			// Perform a re-render.
-			body = &mockObject{}
-			newNode := &mockObject{}
-			document = &mockObject{
-				call: func(name string, args ...interface{}) jsObject {
-					switch name {
-					case "createElement":
-						if len(args) != 1 {
-							panic("len(args) != 1")
-						}
-						switch args[0].(string) {
-						case "body":
-							return body
-						case "div", "noscript":
-							return newNode
-						default:
-							panic("unexpected createElement call")
-						}
-					default:
-						panic(fmt.Sprintf("unexpected call to %q", name))
-					}
-				},
-			}
-			global = &mockObject{
-				get: map[string]jsObject{
-					"document": document,
-					"performance": &mockObject{
-						call: func(name string, args ...interface{}) jsObject {
-							if name != "now" {
-								panic(fmt.Sprintf("expected call to now, not %q", name))
-							}
-							if len(args) != 0 {
-								panic("len(args) != 0")
-							}
-							return &mockObject{floatValue: 0}
-						},
-					},
-				},
-				call: func(name string, args ...interface{}) jsObject {
-					if name != "requestAnimationFrame" {
-						panic(fmt.Sprintf("expected call to requestAnimationFrame, not %q", name))
-					}
-					if len(args) != 1 {
-						panic("len(args) != 1")
-					}
-					var ok bool
-					if renderCallback, ok = args[0].(func(float64)); !ok {
-						panic("incorrect argument to requestAnimationFrame")
-					}
-					return &mockObject{intValue: 0}
-				},
-			}
-
 			comp.id = "modified"
 			comp.render = func() ComponentOrHTML {
 				renderCalled++
@@ -1819,10 +799,11 @@ func TestRerender_Nested(t *testing.T) {
 				return false
 			}
 			Rerender(comp)
-			renderCallback(0)
-			if renderCalled != 2 {
-				t.Fatal("renderCalled != 2")
-			}
+
+			// Invoke the render callback.
+			ts.ints.mock(`global.Call("requestAnimationFrame", func(float64))`, 0)
+			ts.callbacks[`global.Call("requestAnimationFrame", func(float64))`].(func(float64))(0)
+
 			if skipRenderCalled != 1 {
 				t.Fatal("skipRenderCalled != 1")
 			}
@@ -1832,9 +813,6 @@ func TestRerender_Nested(t *testing.T) {
 			if comp.Context().prevRenderComponent.(*componentFunc).id != "modified" {
 				t.Fatal(`comp.Context().prevRenderComponent.(*componentFunc).id != "modified"`)
 			}
-			if bodyAppendChild != newNode {
-				t.Fatal("bodyAppendChild != newNode")
-			}
 		})
 	}
 }
@@ -1865,47 +843,11 @@ func TestRenderBody_ExpectsBody(t *testing.T) {
 	}
 	for _, c := range cases {
 		t.Run(c.name, func(t *testing.T) {
-			document := &mockObject{
-				call: func(name string, args ...interface{}) jsObject {
-					switch name {
-					case "createElement", "createTextNode":
-						if len(args) != 1 {
-							panic("len(args) != 1")
-						}
-						return &mockObject{}
-					default:
-						panic(fmt.Sprintf("unexpected call to %q", name))
-					}
-				},
-			}
-			global = &mockObject{
-				get: map[string]jsObject{
-					"document": document,
-					"performance": &mockObject{
-						call: func(name string, args ...interface{}) jsObject {
-							if name != "now" {
-								panic(fmt.Sprintf("expected call to now, not %q", name))
-							}
-							if len(args) != 0 {
-								panic("len(args) != 0")
-							}
-							return &mockObject{floatValue: 0}
-						},
-					},
-				},
-				call: func(name string, args ...interface{}) jsObject {
-					if name != "requestAnimationFrame" {
-						panic(fmt.Sprintf("expected call to requestAnimationFrame, not %q", name))
-					}
-					if len(args) != 1 {
-						panic("len(args) != 1")
-					}
-					if _, ok := args[0].(func(float64)); !ok {
-						panic("incorrect argument to requestAnimationFrame")
-					}
-					return &mockObject{intValue: 0}
-				},
-			}
+			ts := testSuite(t, "TestRenderBody_ExpectsBody__"+c.name)
+			defer ts.done()
+
+			ts.ints.mock(`global.Call("requestAnimationFrame", func(float64))`, 0)
+
 			var gotPanic string
 			func() {
 				defer func() {
@@ -1931,60 +873,11 @@ func TestRenderBody_ExpectsBody(t *testing.T) {
 // TestRenderBody_RenderSkipper_Skip tests that RenderBody panics when the
 // component's SkipRender method returns skip == true.
 func TestRenderBody_RenderSkipper_Skip(t *testing.T) {
-	body := &mockObject{}
-	document := &mockObject{
-		call: func(name string, args ...interface{}) jsObject {
-			if name != "createElement" {
-				panic(fmt.Sprintf("expected call to createElement, not %q", name))
-			}
-			if len(args) != 1 {
-				panic("len(args) != 1")
-			}
-			if args[0].(string) != "body" {
-				panic(`args[0].(string) != "body"`)
-			}
-			return body
-		},
-		get: map[string]jsObject{
-			"readyState": &mockObject{stringValue: "complete"},
-		},
-		set: func(key string, value interface{}) {
-			if key != "body" {
-				panic(fmt.Sprintf(`expected document.set "body", not %q`, key))
-			}
-			if value != body {
-				panic(fmt.Sprintf(`expected document.set body value, not %T %+v`, value, value))
-			}
-		},
-	}
-	global = &mockObject{
-		get: map[string]jsObject{
-			"document": document,
-			"performance": &mockObject{
-				call: func(name string, args ...interface{}) jsObject {
-					if name != "now" {
-						panic(fmt.Sprintf("expected call to now, not %q", name))
-					}
-					if len(args) != 0 {
-						panic("len(args) != 0")
-					}
-					return &mockObject{floatValue: 0}
-				},
-			},
-		},
-		call: func(name string, args ...interface{}) jsObject {
-			if name != "requestAnimationFrame" {
-				panic(fmt.Sprintf("expected call to requestAnimationFrame, not %q", name))
-			}
-			if len(args) != 1 {
-				panic("len(args) != 1")
-			}
-			if _, ok := args[0].(func(float64)); !ok {
-				panic("incorrect argument to requestAnimationFrame")
-			}
-			return &mockObject{intValue: 0}
-		},
-	}
+	ts := testSuite(t, "TestRenderBody_RenderSkipper_Skip")
+	defer ts.done()
+
+	ts.ints.mock(`global.Call("requestAnimationFrame", func(float64))`, 0)
+
 	comp := &componentFunc{
 		render: func() ComponentOrHTML {
 			return Tag("body")
@@ -2008,220 +901,48 @@ func TestRenderBody_RenderSkipper_Skip(t *testing.T) {
 // standard case of rendering into the "body" tag when the DOM is in a loaded
 // state.
 func TestRenderBody_Standard_loaded(t *testing.T) {
-	body := &mockObject{}
-	bodySet := false
-	document := &mockObject{
-		call: func(name string, args ...interface{}) jsObject {
-			if name != "createElement" {
-				panic(fmt.Sprintf("expected call to createElement, not %q", name))
-			}
-			if len(args) != 1 {
-				panic("len(args) != 1")
-			}
-			if args[0].(string) != "body" {
-				panic(`args[0].(string) != "body"`)
-			}
-			return body
-		},
-		get: map[string]jsObject{
-			"readyState": &mockObject{stringValue: "complete"},
-		},
-		set: func(key string, value interface{}) {
-			if key != "body" {
-				panic(fmt.Sprintf(`expected document.set "body", not %q`, key))
-			}
-			if value != body {
-				panic(fmt.Sprintf(`expected document.set body value, not %T %+v`, value, value))
-			}
-			bodySet = true
-		},
-	}
-	global = &mockObject{
-		get: map[string]jsObject{
-			"document": document,
-			"performance": &mockObject{
-				call: func(name string, args ...interface{}) jsObject {
-					if name != "now" {
-						panic(fmt.Sprintf("expected call to now, not %q", name))
-					}
-					if len(args) != 0 {
-						panic("len(args) != 0")
-					}
-					return &mockObject{floatValue: 0}
-				},
-			},
-		},
-		call: func(name string, args ...interface{}) jsObject {
-			if name != "requestAnimationFrame" {
-				panic(fmt.Sprintf("expected call to requestAnimationFrame, not %q", name))
-			}
-			if len(args) != 1 {
-				panic("len(args) != 1")
-			}
-			if _, ok := args[0].(func(float64)); !ok {
-				panic("incorrect argument to requestAnimationFrame")
-			}
-			return &mockObject{intValue: 0}
-		},
-	}
+	ts := testSuite(t, "TestRenderBody_Standard_loaded")
+	defer ts.done()
+
+	ts.strings.mock(`global.Get("document").Get("readyState")`, "loaded")
+	ts.ints.mock(`global.Call("requestAnimationFrame", func(float64))`, 0)
+
 	RenderBody(&componentFunc{
 		render: func() ComponentOrHTML {
 			return Tag("body")
 		},
 	})
-	if !bodySet {
-		t.Fatalf("expected document.body to be set")
-	}
 }
 
 // TestRenderBody_Standard_loading tests that RenderBody properly handles the
 // standard case of rendering into the "body" tag when the DOM is in a loading
 // state.
 func TestRenderBody_Standard_loading(t *testing.T) {
-	body := &mockObject{}
-	bodySet := false
-	var domLoadedEventListener func()
-	document := &mockObject{
-		call: func(name string, args ...interface{}) jsObject {
-			switch name {
-			case "createElement":
-				if len(args) != 1 {
-					panic("len(args) != 1")
-				}
-				if args[0].(string) != "body" {
-					panic(`args[0].(string) != "body"`)
-				}
-				return body
-			case "addEventListener":
-				if len(args) != 2 {
-					panic("len(args) != 2")
-				}
-				if args[0].(string) != "DOMContentLoaded" {
-					panic(`args[0].(string) != "DOMContentLoaded"`)
-				}
-				domLoadedEventListener = args[1].(func())
-				return nil
-			default:
-				panic(fmt.Sprintf("unexpected call to %q", name))
-			}
-		},
-		get: map[string]jsObject{
-			"readyState": &mockObject{stringValue: "loading"},
-		},
-		set: func(key string, value interface{}) {
-			if key != "body" {
-				panic(fmt.Sprintf(`expected document.set "body", not %q`, key))
-			}
-			if value != body {
-				panic(fmt.Sprintf(`expected document.set body value, not %T %+v`, value, value))
-			}
-			bodySet = true
-		},
-	}
-	global = &mockObject{
-		get: map[string]jsObject{
-			"document": document,
-			"performance": &mockObject{
-				call: func(name string, args ...interface{}) jsObject {
-					if name != "now" {
-						panic(fmt.Sprintf("expected call to now, not %q", name))
-					}
-					if len(args) != 0 {
-						panic("len(args) != 0")
-					}
-					return &mockObject{floatValue: 0}
-				},
-			},
-		},
-		call: func(name string, args ...interface{}) jsObject {
-			if name != "requestAnimationFrame" {
-				panic(fmt.Sprintf("expected call to requestAnimationFrame, not %q", name))
-			}
-			if len(args) != 1 {
-				panic("len(args) != 1")
-			}
-			if _, ok := args[0].(func(float64)); !ok {
-				panic("incorrect argument to requestAnimationFrame")
-			}
-			return &mockObject{intValue: 0}
-		},
-	}
+	ts := testSuite(t, "TestRenderBody_Standard_loading")
+	defer ts.done()
+
+	ts.strings.mock(`global.Get("document").Get("readyState")`, "loading")
+	ts.ints.mock(`global.Call("requestAnimationFrame", func(float64))`, 0)
+
 	RenderBody(&componentFunc{
 		render: func() ComponentOrHTML {
 			return Tag("body")
 		},
 	})
-	if domLoadedEventListener == nil {
-		t.Fatalf("domLoadedEventListener == nil")
-	}
-	if bodySet {
-		t.Fatalf("expected document.body to NOT be set")
-	}
-	domLoadedEventListener()
-	if !bodySet {
-		t.Fatalf("expected document.body to be set")
-	}
+
+	ts.record("(invoking DOMContentLoaded event listener)")
+	ts.callbacks[`global.Get("document").Call("addEventListener", "DOMContentLoaded", func())`].(func())()
 }
 
 // TestRenderBody_Nested tests that RenderBody properly handles nested
 // Components.
 func TestRenderBody_Nested(t *testing.T) {
-	body := &mockObject{}
-	bodySet := false
-	document := &mockObject{
-		call: func(name string, args ...interface{}) jsObject {
-			if name != "createElement" {
-				panic(fmt.Sprintf("expected call to createElement, not %q", name))
-			}
-			if len(args) != 1 {
-				panic("len(args) != 1")
-			}
-			if args[0].(string) != "body" {
-				panic(`args[0].(string) != "body"`)
-			}
-			return body
-		},
-		get: map[string]jsObject{
-			"readyState": &mockObject{stringValue: "complete"},
-		},
-		set: func(key string, value interface{}) {
-			if key != "body" {
-				panic(fmt.Sprintf(`expected document.set "body", not %q`, key))
-			}
-			if value != body {
-				panic(fmt.Sprintf(`expected document.set body value, not %T %+v`, value, value))
-			}
-			bodySet = true
-		},
-	}
-	global = &mockObject{
-		get: map[string]jsObject{
-			"document": document,
-			"performance": &mockObject{
-				call: func(name string, args ...interface{}) jsObject {
-					if name != "now" {
-						panic(fmt.Sprintf("expected call to now, not %q", name))
-					}
-					if len(args) != 0 {
-						panic("len(args) != 0")
-					}
-					return &mockObject{floatValue: 0}
-				},
-			},
-		},
-		call: func(name string, args ...interface{}) jsObject {
-			if name != "requestAnimationFrame" {
-				panic(fmt.Sprintf("expected call to requestAnimationFrame, not %q", name))
-			}
-			if len(args) != 1 {
-				panic("len(args) != 1")
-			}
-			if _, ok := args[0].(func(float64)); !ok {
-				panic("incorrect argument to requestAnimationFrame")
-			}
-			return &mockObject{intValue: 0}
-		},
-	}
+	ts := testSuite(t, "TestRenderBody_Nested")
+	defer ts.done()
+
+	ts.strings.mock(`global.Get("document").Get("readyState")`, "complete")
+	ts.ints.mock(`global.Call("requestAnimationFrame", func(float64))`, 0)
+
 	RenderBody(&componentFunc{
 		render: func() ComponentOrHTML {
 			return &componentFunc{
@@ -2235,145 +956,22 @@ func TestRenderBody_Nested(t *testing.T) {
 			}
 		},
 	})
-	if !bodySet {
-		t.Fatalf("expected document.body to be set")
-	}
 }
 
+// TestSetTitle tests that the SetTitle function performs the correct DOM
+// operations.
 func TestSetTitle(t *testing.T) {
-	titleSet := ""
-	document := &mockObject{
-		set: func(key string, value interface{}) {
-			if key != "title" {
-				panic(fmt.Sprintf(`expected document.set "title", not %q`, key))
-			}
-			titleSet = value.(string)
-		},
-	}
-	global = &mockObject{
-		get: map[string]jsObject{
-			"document": document,
-		},
-	}
-	want := "foobar"
-	SetTitle(want)
-	if titleSet != want {
-		t.Fatalf("titleSet is %q, want %q", titleSet, want)
-	}
-}
+	ts := testSuite(t, "TestSetTitle")
+	defer ts.done()
 
-func TestAddStylesheet(t *testing.T) {
-	linkSet := map[string]interface{}{}
-	link := &mockObject{
-		set: func(key string, value interface{}) {
-			linkSet[key] = value
-		},
-	}
-	appendedToHead := false
-	head := &mockObject{
-		call: func(name string, args ...interface{}) jsObject {
-			switch name {
-			case "appendChild":
-				if len(args) != 1 {
-					panic("len(args) != 1")
-				}
-				if args[0] != link {
-					panic(`args[0] != link`)
-				}
-				appendedToHead = true
-				return nil
-			default:
-				panic(fmt.Sprintf("unexpected call to %q", name))
-			}
-		},
-	}
-	document := &mockObject{
-		call: func(name string, args ...interface{}) jsObject {
-			switch name {
-			case "createElement":
-				if len(args) != 1 {
-					panic("len(args) != 1")
-				}
-				if args[0].(string) != "link" {
-					panic(`args[0].(string) != "link"`)
-				}
-				return link
-			default:
-				panic(fmt.Sprintf("unexpected call to %q", name))
-			}
-		},
-		set: func(key string, value interface{}) {
-			if key != "title" {
-				panic(fmt.Sprintf(`expected document.set "title", not %q`, key))
-			}
-		},
-		get: map[string]jsObject{
-			"head": head,
-		},
-	}
-	global = &mockObject{
-		get: map[string]jsObject{
-			"document": document,
-		},
-	}
-	url := "https://google.com/foobar.css"
-	AddStylesheet(url)
-	if !appendedToHead {
-		t.Fatal("expected link to be appended to document.head")
-	}
-	if linkSet["rel"] != "stylesheet" {
-		t.Fatal(`linkSet["rel"] != "stylesheet"`)
-	}
-	if linkSet["href"] != url {
-		t.Fatal(`linkSet["href"] != url`)
-	}
+	SetTitle("foobartitle")
 }
 
-// sortedMapString returns the map converted to a string, but sorted.
-func sortedMapString(m map[string]interface{}) string {
-	var strs []string
-	for k, v := range m {
-		strs = append(strs, fmt.Sprintf("%v:%v", k, v))
-	}
-	sort.Strings(strs)
-	return strings.Join(strs, " ")
-}
-
-// recoverStr runs f and returns the recovered panic as a string.
-func recoverStr(f func()) (s string) {
-	defer func() {
-		s = fmt.Sprint(recover())
-	}()
-	f()
-	return
-}
-
-type componentFunc struct {
-	Core
-	id         string
-	render     func() ComponentOrHTML
-	skipRender func(prev Component) bool
-}
+// TestAddStylesheet tests that the AddStylesheet performs the correct DOM
+// operations.
+func TestAddStylesheet(t *testing.T) {
+	ts := testSuite(t, "TestAddStylesheet")
+	defer ts.done()
 
-func (c *componentFunc) Render() ComponentOrHTML        { return c.render() }
-func (c *componentFunc) SkipRender(prev Component) bool { return c.skipRender(prev) }
-
-type mockObject struct {
-	set         func(key string, value interface{})
-	get         map[string]jsObject
-	delete      func(key string)
-	call        func(name string, args ...interface{}) jsObject
-	stringValue string
-	boolValue   bool
-	intValue    int
-	floatValue  float64
+	AddStylesheet("https://google.com/foobar.css")
 }
-
-func (w *mockObject) Set(key string, value interface{})              { w.set(key, value) }
-func (w *mockObject) Get(key string) jsObject                        { return w.get[key] }
-func (w *mockObject) Delete(key string)                              { w.delete(key) }
-func (w *mockObject) Call(name string, args ...interface{}) jsObject { return w.call(name, args...) }
-func (w *mockObject) String() string                                 { return w.stringValue }
-func (w *mockObject) Bool() bool                                     { return w.boolValue }
-func (w *mockObject) Int() int                                       { return w.intValue }
-func (w *mockObject) Float() float64                                 { return w.floatValue }
diff --git a/testdata/TestAddStylesheet.want.txt b/testdata/TestAddStylesheet.want.txt
new file mode 100755
index 00000000..b42ddb50
--- /dev/null
+++ b/testdata/TestAddStylesheet.want.txt
@@ -0,0 +1,7 @@
+global.Get("document")
+global.Get("document").Call("createElement", "link")
+global.Get("document").Call("createElement", "link").Set("rel", "stylesheet")
+global.Get("document").Call("createElement", "link").Set("href", "https://google.com/foobar.css")
+global.Get("document")
+global.Get("document").Get("head")
+global.Get("document").Get("head").Call("appendChild", jsObject(global.Get("document").Call("createElement", "link")))
\ No newline at end of file
diff --git a/testdata/TestHTML_reconcile_nil__add_event_listener.want.txt b/testdata/TestHTML_reconcile_nil__add_event_listener.want.txt
new file mode 100755
index 00000000..48c77b97
--- /dev/null
+++ b/testdata/TestHTML_reconcile_nil__add_event_listener.want.txt
@@ -0,0 +1,7 @@
+global.Get("document")
+global.Get("document").Call("createElement", "div")
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("style")
+global.Get("document").Call("createElement", "div").Call("addEventListener", "click", func(*js.Object))
+global.Get("document").Call("createElement", "div").Call("addEventListener", "keydown", func(*js.Object))
\ No newline at end of file
diff --git a/testdata/TestHTML_reconcile_nil__attributes.want.txt b/testdata/TestHTML_reconcile_nil__attributes.want.txt
new file mode 100755
index 00000000..95c04379
--- /dev/null
+++ b/testdata/TestHTML_reconcile_nil__attributes.want.txt
@@ -0,0 +1,7 @@
+global.Get("document")
+global.Get("document").Call("createElement", "div")
+global.Get("document").Call("createElement", "div").Call("setAttribute", "a", 1)
+global.Get("document").Call("createElement", "div").Call("setAttribute", "b", "2foobar")
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("style")
\ No newline at end of file
diff --git a/testdata/TestHTML_reconcile_nil__children.want.txt b/testdata/TestHTML_reconcile_nil__children.want.txt
new file mode 100755
index 00000000..3618d995
--- /dev/null
+++ b/testdata/TestHTML_reconcile_nil__children.want.txt
@@ -0,0 +1,17 @@
+global.Get("document")
+global.Get("document").Call("createElement", "div")
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("style")
+global.Get("document")
+global.Get("document").Call("createElement", "div")
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("style")
+global.Get("document")
+global.Get("document").Call("createElement", "div")
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("style")
+global.Get("document").Call("createElement", "div").Call("appendChild", jsObject(global.Get("document").Call("createElement", "div")))
+global.Get("document").Call("createElement", "div").Call("appendChild", jsObject(global.Get("document").Call("createElement", "div")))
\ No newline at end of file
diff --git a/testdata/TestHTML_reconcile_nil__children_render_nil.want.txt b/testdata/TestHTML_reconcile_nil__children_render_nil.want.txt
new file mode 100755
index 00000000..79d7c476
--- /dev/null
+++ b/testdata/TestHTML_reconcile_nil__children_render_nil.want.txt
@@ -0,0 +1,17 @@
+global.Get("document")
+global.Get("document").Call("createElement", "div")
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("style")
+global.Get("document")
+global.Get("document").Call("createElement", "div")
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("style")
+global.Get("document")
+global.Get("document").Call("createElement", "noscript")
+global.Get("document").Call("createElement", "noscript").Get("classList")
+global.Get("document").Call("createElement", "noscript").Get("dataset")
+global.Get("document").Call("createElement", "noscript").Get("style")
+global.Get("document").Call("createElement", "div").Call("appendChild", jsObject(global.Get("document").Call("createElement", "noscript")))
+global.Get("document").Call("createElement", "div").Call("appendChild", jsObject(global.Get("document").Call("createElement", "div")))
\ No newline at end of file
diff --git a/testdata/TestHTML_reconcile_nil__create_element.want.txt b/testdata/TestHTML_reconcile_nil__create_element.want.txt
new file mode 100755
index 00000000..c4344f07
--- /dev/null
+++ b/testdata/TestHTML_reconcile_nil__create_element.want.txt
@@ -0,0 +1,5 @@
+global.Get("document")
+global.Get("document").Call("createElement", "strong")
+global.Get("document").Call("createElement", "strong").Get("classList")
+global.Get("document").Call("createElement", "strong").Get("dataset")
+global.Get("document").Call("createElement", "strong").Get("style")
\ No newline at end of file
diff --git a/testdata/TestHTML_reconcile_nil__create_element_ns.want.txt b/testdata/TestHTML_reconcile_nil__create_element_ns.want.txt
new file mode 100755
index 00000000..59ae4505
--- /dev/null
+++ b/testdata/TestHTML_reconcile_nil__create_element_ns.want.txt
@@ -0,0 +1,5 @@
+global.Get("document")
+global.Get("document").Call("createElementNS", "foobar", "strong")
+global.Get("document").Call("createElementNS", "foobar", "strong").Get("classList")
+global.Get("document").Call("createElementNS", "foobar", "strong").Get("dataset")
+global.Get("document").Call("createElementNS", "foobar", "strong").Get("style")
\ No newline at end of file
diff --git a/testdata/TestHTML_reconcile_nil__create_text_node.want.txt b/testdata/TestHTML_reconcile_nil__create_text_node.want.txt
new file mode 100755
index 00000000..6c94c374
--- /dev/null
+++ b/testdata/TestHTML_reconcile_nil__create_text_node.want.txt
@@ -0,0 +1,5 @@
+global.Get("document")
+global.Get("document").Call("createTextNode", "hello")
+global.Get("document").Call("createTextNode", "hello").Get("classList")
+global.Get("document").Call("createTextNode", "hello").Get("dataset")
+global.Get("document").Call("createTextNode", "hello").Get("style")
\ No newline at end of file
diff --git a/testdata/TestHTML_reconcile_nil__dataset.want.txt b/testdata/TestHTML_reconcile_nil__dataset.want.txt
new file mode 100755
index 00000000..23e3ed03
--- /dev/null
+++ b/testdata/TestHTML_reconcile_nil__dataset.want.txt
@@ -0,0 +1,7 @@
+global.Get("document")
+global.Get("document").Call("createElement", "div")
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("dataset").Set("a", "1")
+global.Get("document").Call("createElement", "div").Get("dataset").Set("b", "2foobar")
+global.Get("document").Call("createElement", "div").Get("style")
\ No newline at end of file
diff --git a/testdata/TestHTML_reconcile_nil__inner_html.want.txt b/testdata/TestHTML_reconcile_nil__inner_html.want.txt
new file mode 100755
index 00000000..8e5d7a55
--- /dev/null
+++ b/testdata/TestHTML_reconcile_nil__inner_html.want.txt
@@ -0,0 +1,6 @@
+global.Get("document")
+global.Get("document").Call("createElement", "div")
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("style")
+global.Get("document").Call("createElement", "div").Set("innerHTML", "<p>hello</p>")
\ No newline at end of file
diff --git a/testdata/TestHTML_reconcile_nil__properties.want.txt b/testdata/TestHTML_reconcile_nil__properties.want.txt
new file mode 100755
index 00000000..16c59cc5
--- /dev/null
+++ b/testdata/TestHTML_reconcile_nil__properties.want.txt
@@ -0,0 +1,7 @@
+global.Get("document")
+global.Get("document").Call("createElement", "div")
+global.Get("document").Call("createElement", "div").Set("a", 1)
+global.Get("document").Call("createElement", "div").Set("b", "2foobar")
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("style")
\ No newline at end of file
diff --git a/testdata/TestHTML_reconcile_nil__style.want.txt b/testdata/TestHTML_reconcile_nil__style.want.txt
new file mode 100755
index 00000000..cbc47828
--- /dev/null
+++ b/testdata/TestHTML_reconcile_nil__style.want.txt
@@ -0,0 +1,7 @@
+global.Get("document")
+global.Get("document").Call("createElement", "div")
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("style")
+global.Get("document").Call("createElement", "div").Get("style").Call("setProperty", "a", "1")
+global.Get("document").Call("createElement", "div").Get("style").Call("setProperty", "b", "2foobar")
\ No newline at end of file
diff --git a/testdata/TestHTML_reconcile_std__attributes__diff.want.txt b/testdata/TestHTML_reconcile_std__attributes__diff.want.txt
new file mode 100755
index 00000000..da4ca2fd
--- /dev/null
+++ b/testdata/TestHTML_reconcile_std__attributes__diff.want.txt
@@ -0,0 +1,16 @@
+global.Get("document")
+global.Get("document").Call("createElement", "div")
+global.Get("document").Call("createElement", "div").Call("setAttribute", "a", 1)
+global.Get("document").Call("createElement", "div").Call("setAttribute", "b", "2foobar")
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("style")
+(first reconcile done)
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("style")
+global.Get("document").Call("createElement", "div").Call("setAttribute", "a", 3)
+global.Get("document").Call("createElement", "div").Call("setAttribute", "b", "4foobar")
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("style")
\ No newline at end of file
diff --git a/testdata/TestHTML_reconcile_std__attributes__remove.want.txt b/testdata/TestHTML_reconcile_std__attributes__remove.want.txt
new file mode 100755
index 00000000..a5710c41
--- /dev/null
+++ b/testdata/TestHTML_reconcile_std__attributes__remove.want.txt
@@ -0,0 +1,16 @@
+global.Get("document")
+global.Get("document").Call("createElement", "div")
+global.Get("document").Call("createElement", "div").Call("setAttribute", "a", 1)
+global.Get("document").Call("createElement", "div").Call("setAttribute", "b", "2foobar")
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("style")
+(first reconcile done)
+global.Get("document").Call("createElement", "div").Call("removeAttribute", "b")
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("style")
+global.Get("document").Call("createElement", "div").Call("setAttribute", "a", 3)
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("style")
\ No newline at end of file
diff --git a/testdata/TestHTML_reconcile_std__class__combo.want.txt b/testdata/TestHTML_reconcile_std__class__combo.want.txt
new file mode 100755
index 00000000..31d919a8
--- /dev/null
+++ b/testdata/TestHTML_reconcile_std__class__combo.want.txt
@@ -0,0 +1,18 @@
+global.Get("document")
+global.Get("document").Call("createElement", "div")
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("classList").Call("add", "a")
+global.Get("document").Call("createElement", "div").Get("classList").Call("add", "b")
+global.Get("document").Call("createElement", "div").Get("classList").Call("add", "c")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("style")
+(first reconcile done)
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("classList").Call("remove", "b")
+global.Get("document").Call("createElement", "div").Get("classList").Call("remove", "c")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("style")
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("classList").Call("add", "d")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("style")
\ No newline at end of file
diff --git a/testdata/TestHTML_reconcile_std__class__diff.want.txt b/testdata/TestHTML_reconcile_std__class__diff.want.txt
new file mode 100755
index 00000000..85bdaa06
--- /dev/null
+++ b/testdata/TestHTML_reconcile_std__class__diff.want.txt
@@ -0,0 +1,16 @@
+global.Get("document")
+global.Get("document").Call("createElement", "div")
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("classList").Call("add", "a")
+global.Get("document").Call("createElement", "div").Get("classList").Call("add", "b")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("style")
+(first reconcile done)
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("classList").Call("remove", "b")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("style")
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("classList").Call("add", "c")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("style")
\ No newline at end of file
diff --git a/testdata/TestHTML_reconcile_std__class__map.want.txt b/testdata/TestHTML_reconcile_std__class__map.want.txt
new file mode 100755
index 00000000..31201e38
--- /dev/null
+++ b/testdata/TestHTML_reconcile_std__class__map.want.txt
@@ -0,0 +1,15 @@
+global.Get("document")
+global.Get("document").Call("createElement", "div")
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("classList").Call("add", "a")
+global.Get("document").Call("createElement", "div").Get("classList").Call("add", "b")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("style")
+(first reconcile done)
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("classList").Call("remove", "b")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("style")
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("style")
\ No newline at end of file
diff --git a/testdata/TestHTML_reconcile_std__class__map_toggle.want.txt b/testdata/TestHTML_reconcile_std__class__map_toggle.want.txt
new file mode 100755
index 00000000..31201e38
--- /dev/null
+++ b/testdata/TestHTML_reconcile_std__class__map_toggle.want.txt
@@ -0,0 +1,15 @@
+global.Get("document")
+global.Get("document").Call("createElement", "div")
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("classList").Call("add", "a")
+global.Get("document").Call("createElement", "div").Get("classList").Call("add", "b")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("style")
+(first reconcile done)
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("classList").Call("remove", "b")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("style")
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("style")
\ No newline at end of file
diff --git a/testdata/TestHTML_reconcile_std__class__multi.want.txt b/testdata/TestHTML_reconcile_std__class__multi.want.txt
new file mode 100755
index 00000000..85bdaa06
--- /dev/null
+++ b/testdata/TestHTML_reconcile_std__class__multi.want.txt
@@ -0,0 +1,16 @@
+global.Get("document")
+global.Get("document").Call("createElement", "div")
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("classList").Call("add", "a")
+global.Get("document").Call("createElement", "div").Get("classList").Call("add", "b")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("style")
+(first reconcile done)
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("classList").Call("remove", "b")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("style")
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("classList").Call("add", "c")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("style")
\ No newline at end of file
diff --git a/testdata/TestHTML_reconcile_std__class__remove.want.txt b/testdata/TestHTML_reconcile_std__class__remove.want.txt
new file mode 100755
index 00000000..31201e38
--- /dev/null
+++ b/testdata/TestHTML_reconcile_std__class__remove.want.txt
@@ -0,0 +1,15 @@
+global.Get("document")
+global.Get("document").Call("createElement", "div")
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("classList").Call("add", "a")
+global.Get("document").Call("createElement", "div").Get("classList").Call("add", "b")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("style")
+(first reconcile done)
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("classList").Call("remove", "b")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("style")
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("style")
\ No newline at end of file
diff --git a/testdata/TestHTML_reconcile_std__dataset__diff.want.txt b/testdata/TestHTML_reconcile_std__dataset__diff.want.txt
new file mode 100755
index 00000000..ed16c11f
--- /dev/null
+++ b/testdata/TestHTML_reconcile_std__dataset__diff.want.txt
@@ -0,0 +1,16 @@
+global.Get("document")
+global.Get("document").Call("createElement", "div")
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("dataset").Set("a", "1")
+global.Get("document").Call("createElement", "div").Get("dataset").Set("b", "2foobar")
+global.Get("document").Call("createElement", "div").Get("style")
+(first reconcile done)
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("style")
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("dataset").Set("a", "3")
+global.Get("document").Call("createElement", "div").Get("dataset").Set("b", "4foobar")
+global.Get("document").Call("createElement", "div").Get("style")
\ No newline at end of file
diff --git a/testdata/TestHTML_reconcile_std__dataset__remove.want.txt b/testdata/TestHTML_reconcile_std__dataset__remove.want.txt
new file mode 100755
index 00000000..f5408d5e
--- /dev/null
+++ b/testdata/TestHTML_reconcile_std__dataset__remove.want.txt
@@ -0,0 +1,16 @@
+global.Get("document")
+global.Get("document").Call("createElement", "div")
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("dataset").Set("a", "1")
+global.Get("document").Call("createElement", "div").Get("dataset").Set("b", "2foobar")
+global.Get("document").Call("createElement", "div").Get("style")
+(first reconcile done)
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("dataset").Delete("b")
+global.Get("document").Call("createElement", "div").Get("style")
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("dataset").Set("a", "3")
+global.Get("document").Call("createElement", "div").Get("style")
\ No newline at end of file
diff --git a/testdata/TestHTML_reconcile_std__event_listener_diff.want.txt b/testdata/TestHTML_reconcile_std__event_listener_diff.want.txt
new file mode 100755
index 00000000..355253f2
--- /dev/null
+++ b/testdata/TestHTML_reconcile_std__event_listener_diff.want.txt
@@ -0,0 +1,18 @@
+global.Get("document")
+global.Get("document").Call("createElement", "div")
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("style")
+global.Get("document").Call("createElement", "div").Call("addEventListener", "click", func(*js.Object))
+global.Get("document").Call("createElement", "div").Call("addEventListener", "keydown", func(*js.Object))
+(expected two added event listeners above)
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("style")
+global.Get("document").Call("createElement", "div").Call("removeEventListener", "click", func(*js.Object))
+global.Get("document").Call("createElement", "div").Call("removeEventListener", "keydown", func(*js.Object))
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("style")
+global.Get("document").Call("createElement", "div").Call("addEventListener", "click", func(*js.Object))
+(expected two removed, one added event listeners above)
\ No newline at end of file
diff --git a/testdata/TestHTML_reconcile_std__properties__diff.want.txt b/testdata/TestHTML_reconcile_std__properties__diff.want.txt
new file mode 100755
index 00000000..7049fc9d
--- /dev/null
+++ b/testdata/TestHTML_reconcile_std__properties__diff.want.txt
@@ -0,0 +1,16 @@
+global.Get("document")
+global.Get("document").Call("createElement", "div")
+global.Get("document").Call("createElement", "div").Set("a", 1)
+global.Get("document").Call("createElement", "div").Set("b", "2foobar")
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("style")
+(first reconcile done)
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("style")
+global.Get("document").Call("createElement", "div").Set("a", 3)
+global.Get("document").Call("createElement", "div").Set("b", "4foobar")
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("style")
\ No newline at end of file
diff --git a/testdata/TestHTML_reconcile_std__properties__remove.want.txt b/testdata/TestHTML_reconcile_std__properties__remove.want.txt
new file mode 100755
index 00000000..0472b14f
--- /dev/null
+++ b/testdata/TestHTML_reconcile_std__properties__remove.want.txt
@@ -0,0 +1,16 @@
+global.Get("document")
+global.Get("document").Call("createElement", "div")
+global.Get("document").Call("createElement", "div").Set("a", 1)
+global.Get("document").Call("createElement", "div").Set("b", "2foobar")
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("style")
+(first reconcile done)
+global.Get("document").Call("createElement", "div").Delete("b")
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("style")
+global.Get("document").Call("createElement", "div").Set("a", 3)
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("style")
\ No newline at end of file
diff --git a/testdata/TestHTML_reconcile_std__properties__replaced_elem_diff.want.txt b/testdata/TestHTML_reconcile_std__properties__replaced_elem_diff.want.txt
new file mode 100755
index 00000000..c7f40876
--- /dev/null
+++ b/testdata/TestHTML_reconcile_std__properties__replaced_elem_diff.want.txt
@@ -0,0 +1,15 @@
+global.Get("document")
+global.Get("document").Call("createElement", "div")
+global.Get("document").Call("createElement", "div").Set("a", 1)
+global.Get("document").Call("createElement", "div").Set("b", "2foobar")
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("style")
+(first reconcile done)
+global.Get("document")
+global.Get("document").Call("createElement", "span")
+global.Get("document").Call("createElement", "span").Set("a", 3)
+global.Get("document").Call("createElement", "span").Set("b", "4foobar")
+global.Get("document").Call("createElement", "span").Get("classList")
+global.Get("document").Call("createElement", "span").Get("dataset")
+global.Get("document").Call("createElement", "span").Get("style")
\ No newline at end of file
diff --git a/testdata/TestHTML_reconcile_std__properties__replaced_elem_shared.want.txt b/testdata/TestHTML_reconcile_std__properties__replaced_elem_shared.want.txt
new file mode 100755
index 00000000..4aac5d4d
--- /dev/null
+++ b/testdata/TestHTML_reconcile_std__properties__replaced_elem_shared.want.txt
@@ -0,0 +1,15 @@
+global.Get("document")
+global.Get("document").Call("createElement", "div")
+global.Get("document").Call("createElement", "div").Set("a", 1)
+global.Get("document").Call("createElement", "div").Set("b", "2foobar")
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("style")
+(first reconcile done)
+global.Get("document")
+global.Get("document").Call("createElement", "span")
+global.Get("document").Call("createElement", "span").Set("a", 1)
+global.Get("document").Call("createElement", "span").Set("b", "4foobar")
+global.Get("document").Call("createElement", "span").Get("classList")
+global.Get("document").Call("createElement", "span").Get("dataset")
+global.Get("document").Call("createElement", "span").Get("style")
\ No newline at end of file
diff --git a/testdata/TestHTML_reconcile_std__style__diff.want.txt b/testdata/TestHTML_reconcile_std__style__diff.want.txt
new file mode 100755
index 00000000..70c83723
--- /dev/null
+++ b/testdata/TestHTML_reconcile_std__style__diff.want.txt
@@ -0,0 +1,16 @@
+global.Get("document")
+global.Get("document").Call("createElement", "div")
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("style")
+global.Get("document").Call("createElement", "div").Get("style").Call("setProperty", "a", "1")
+global.Get("document").Call("createElement", "div").Get("style").Call("setProperty", "b", "2foobar")
+(first reconcile done)
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("style")
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("style")
+global.Get("document").Call("createElement", "div").Get("style").Call("setProperty", "a", "3")
+global.Get("document").Call("createElement", "div").Get("style").Call("setProperty", "b", "4foobar")
\ No newline at end of file
diff --git a/testdata/TestHTML_reconcile_std__style__remove.want.txt b/testdata/TestHTML_reconcile_std__style__remove.want.txt
new file mode 100755
index 00000000..b1131eff
--- /dev/null
+++ b/testdata/TestHTML_reconcile_std__style__remove.want.txt
@@ -0,0 +1,16 @@
+global.Get("document")
+global.Get("document").Call("createElement", "div")
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("style")
+global.Get("document").Call("createElement", "div").Get("style").Call("setProperty", "a", "1")
+global.Get("document").Call("createElement", "div").Get("style").Call("setProperty", "b", "2foobar")
+(first reconcile done)
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("style")
+global.Get("document").Call("createElement", "div").Get("style").Call("removeProperty", "b")
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("style")
+global.Get("document").Call("createElement", "div").Get("style").Call("setProperty", "a", "3")
\ No newline at end of file
diff --git a/testdata/TestHTML_reconcile_std__text_diff.want.txt b/testdata/TestHTML_reconcile_std__text_diff.want.txt
new file mode 100755
index 00000000..eee5aeb7
--- /dev/null
+++ b/testdata/TestHTML_reconcile_std__text_diff.want.txt
@@ -0,0 +1,6 @@
+global.Get("document")
+global.Get("document").Call("createTextNode", "bar")
+global.Get("document").Call("createTextNode", "bar").Get("classList")
+global.Get("document").Call("createTextNode", "bar").Get("dataset")
+global.Get("document").Call("createTextNode", "bar").Get("style")
+global.Get("document").Call("createTextNode", "bar").Set("nodeValue", "foo")
\ No newline at end of file
diff --git a/testdata/TestHTML_reconcile_std__text_identical.want.txt b/testdata/TestHTML_reconcile_std__text_identical.want.txt
new file mode 100755
index 00000000..4d4b3b11
--- /dev/null
+++ b/testdata/TestHTML_reconcile_std__text_identical.want.txt
@@ -0,0 +1,5 @@
+global.Get("document")
+global.Get("document").Call("createTextNode", "foobar")
+global.Get("document").Call("createTextNode", "foobar").Get("classList")
+global.Get("document").Call("createTextNode", "foobar").Get("dataset")
+global.Get("document").Call("createTextNode", "foobar").Get("style")
\ No newline at end of file
diff --git a/testdata/TestRenderBody_ExpectsBody__div.want.txt b/testdata/TestRenderBody_ExpectsBody__div.want.txt
new file mode 100755
index 00000000..bce71bfd
--- /dev/null
+++ b/testdata/TestRenderBody_ExpectsBody__div.want.txt
@@ -0,0 +1,6 @@
+global.Get("document")
+global.Get("document").Call("createElement", "div")
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("style")
+global.Call("requestAnimationFrame", func(float64))
\ No newline at end of file
diff --git a/testdata/TestRenderBody_ExpectsBody__nil.want.txt b/testdata/TestRenderBody_ExpectsBody__nil.want.txt
new file mode 100755
index 00000000..c5a03b61
--- /dev/null
+++ b/testdata/TestRenderBody_ExpectsBody__nil.want.txt
@@ -0,0 +1,6 @@
+global.Get("document")
+global.Get("document").Call("createElement", "noscript")
+global.Get("document").Call("createElement", "noscript").Get("classList")
+global.Get("document").Call("createElement", "noscript").Get("dataset")
+global.Get("document").Call("createElement", "noscript").Get("style")
+global.Call("requestAnimationFrame", func(float64))
\ No newline at end of file
diff --git a/testdata/TestRenderBody_ExpectsBody__text.want.txt b/testdata/TestRenderBody_ExpectsBody__text.want.txt
new file mode 100755
index 00000000..2f7f77cb
--- /dev/null
+++ b/testdata/TestRenderBody_ExpectsBody__text.want.txt
@@ -0,0 +1,6 @@
+global.Get("document")
+global.Get("document").Call("createTextNode", "Hello world!")
+global.Get("document").Call("createTextNode", "Hello world!").Get("classList")
+global.Get("document").Call("createTextNode", "Hello world!").Get("dataset")
+global.Get("document").Call("createTextNode", "Hello world!").Get("style")
+global.Call("requestAnimationFrame", func(float64))
\ No newline at end of file
diff --git a/testdata/TestRenderBody_Nested.want.txt b/testdata/TestRenderBody_Nested.want.txt
new file mode 100755
index 00000000..019470df
--- /dev/null
+++ b/testdata/TestRenderBody_Nested.want.txt
@@ -0,0 +1,9 @@
+global.Get("document")
+global.Get("document").Call("createElement", "body")
+global.Get("document").Call("createElement", "body").Get("classList")
+global.Get("document").Call("createElement", "body").Get("dataset")
+global.Get("document").Call("createElement", "body").Get("style")
+global.Get("document")
+global.Get("document").Get("readyState")
+global.Get("document").Set("body", jsObject(global.Get("document").Call("createElement", "body")))
+global.Call("requestAnimationFrame", func(float64))
\ No newline at end of file
diff --git a/testdata/TestRenderBody_RenderSkipper_Skip.want.txt b/testdata/TestRenderBody_RenderSkipper_Skip.want.txt
new file mode 100755
index 00000000..d214cc82
--- /dev/null
+++ b/testdata/TestRenderBody_RenderSkipper_Skip.want.txt
@@ -0,0 +1 @@
+global.Call("requestAnimationFrame", func(float64))
\ No newline at end of file
diff --git a/testdata/TestRenderBody_Standard_loaded.want.txt b/testdata/TestRenderBody_Standard_loaded.want.txt
new file mode 100755
index 00000000..019470df
--- /dev/null
+++ b/testdata/TestRenderBody_Standard_loaded.want.txt
@@ -0,0 +1,9 @@
+global.Get("document")
+global.Get("document").Call("createElement", "body")
+global.Get("document").Call("createElement", "body").Get("classList")
+global.Get("document").Call("createElement", "body").Get("dataset")
+global.Get("document").Call("createElement", "body").Get("style")
+global.Get("document")
+global.Get("document").Get("readyState")
+global.Get("document").Set("body", jsObject(global.Get("document").Call("createElement", "body")))
+global.Call("requestAnimationFrame", func(float64))
\ No newline at end of file
diff --git a/testdata/TestRenderBody_Standard_loading.want.txt b/testdata/TestRenderBody_Standard_loading.want.txt
new file mode 100755
index 00000000..de1284a9
--- /dev/null
+++ b/testdata/TestRenderBody_Standard_loading.want.txt
@@ -0,0 +1,11 @@
+global.Get("document")
+global.Get("document").Call("createElement", "body")
+global.Get("document").Call("createElement", "body").Get("classList")
+global.Get("document").Call("createElement", "body").Get("dataset")
+global.Get("document").Call("createElement", "body").Get("style")
+global.Get("document")
+global.Get("document").Get("readyState")
+global.Get("document").Call("addEventListener", "DOMContentLoaded", func())
+global.Call("requestAnimationFrame", func(float64))
+(invoking DOMContentLoaded event listener)
+global.Get("document").Set("body", jsObject(global.Get("document").Call("createElement", "body")))
\ No newline at end of file
diff --git a/testdata/TestRerender_Nested__component_to_html.want.txt b/testdata/TestRerender_Nested__component_to_html.want.txt
new file mode 100755
index 00000000..d8adc033
--- /dev/null
+++ b/testdata/TestRerender_Nested__component_to_html.want.txt
@@ -0,0 +1,23 @@
+global.Get("document")
+global.Get("document").Call("createElement", "body")
+global.Get("document").Call("createElement", "body").Get("classList")
+global.Get("document").Call("createElement", "body").Get("dataset")
+global.Get("document").Call("createElement", "body").Get("style")
+global.Get("document")
+global.Get("document").Get("readyState")
+global.Get("document").Set("body", jsObject(global.Get("document").Call("createElement", "body")))
+global.Call("requestAnimationFrame", func(float64))
+(expect body to be set now)
+global.Get("document").Call("createElement", "body").Get("classList")
+global.Get("document").Call("createElement", "body").Get("dataset")
+global.Get("document").Call("createElement", "body").Get("style")
+global.Get("document").Call("createElement", "body").Get("classList")
+global.Get("document").Call("createElement", "body").Get("dataset")
+global.Get("document").Call("createElement", "body").Get("style")
+global.Get("document")
+global.Get("document").Call("createElement", "div")
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("style")
+global.Get("document").Call("createElement", "body").Call("appendChild", jsObject(global.Get("document").Call("createElement", "div")))
+global.Call("requestAnimationFrame", func(float64))
\ No newline at end of file
diff --git a/testdata/TestRerender_Nested__html_to_component.want.txt b/testdata/TestRerender_Nested__html_to_component.want.txt
new file mode 100755
index 00000000..d8adc033
--- /dev/null
+++ b/testdata/TestRerender_Nested__html_to_component.want.txt
@@ -0,0 +1,23 @@
+global.Get("document")
+global.Get("document").Call("createElement", "body")
+global.Get("document").Call("createElement", "body").Get("classList")
+global.Get("document").Call("createElement", "body").Get("dataset")
+global.Get("document").Call("createElement", "body").Get("style")
+global.Get("document")
+global.Get("document").Get("readyState")
+global.Get("document").Set("body", jsObject(global.Get("document").Call("createElement", "body")))
+global.Call("requestAnimationFrame", func(float64))
+(expect body to be set now)
+global.Get("document").Call("createElement", "body").Get("classList")
+global.Get("document").Call("createElement", "body").Get("dataset")
+global.Get("document").Call("createElement", "body").Get("style")
+global.Get("document").Call("createElement", "body").Get("classList")
+global.Get("document").Call("createElement", "body").Get("dataset")
+global.Get("document").Call("createElement", "body").Get("style")
+global.Get("document")
+global.Get("document").Call("createElement", "div")
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("style")
+global.Get("document").Call("createElement", "body").Call("appendChild", jsObject(global.Get("document").Call("createElement", "div")))
+global.Call("requestAnimationFrame", func(float64))
\ No newline at end of file
diff --git a/testdata/TestRerender_Nested__new_child.want.txt b/testdata/TestRerender_Nested__new_child.want.txt
new file mode 100755
index 00000000..d8adc033
--- /dev/null
+++ b/testdata/TestRerender_Nested__new_child.want.txt
@@ -0,0 +1,23 @@
+global.Get("document")
+global.Get("document").Call("createElement", "body")
+global.Get("document").Call("createElement", "body").Get("classList")
+global.Get("document").Call("createElement", "body").Get("dataset")
+global.Get("document").Call("createElement", "body").Get("style")
+global.Get("document")
+global.Get("document").Get("readyState")
+global.Get("document").Set("body", jsObject(global.Get("document").Call("createElement", "body")))
+global.Call("requestAnimationFrame", func(float64))
+(expect body to be set now)
+global.Get("document").Call("createElement", "body").Get("classList")
+global.Get("document").Call("createElement", "body").Get("dataset")
+global.Get("document").Call("createElement", "body").Get("style")
+global.Get("document").Call("createElement", "body").Get("classList")
+global.Get("document").Call("createElement", "body").Get("dataset")
+global.Get("document").Call("createElement", "body").Get("style")
+global.Get("document")
+global.Get("document").Call("createElement", "div")
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("style")
+global.Get("document").Call("createElement", "body").Call("appendChild", jsObject(global.Get("document").Call("createElement", "div")))
+global.Call("requestAnimationFrame", func(float64))
\ No newline at end of file
diff --git a/testdata/TestRerender_change__new_child.want.txt b/testdata/TestRerender_change__new_child.want.txt
new file mode 100755
index 00000000..d8adc033
--- /dev/null
+++ b/testdata/TestRerender_change__new_child.want.txt
@@ -0,0 +1,23 @@
+global.Get("document")
+global.Get("document").Call("createElement", "body")
+global.Get("document").Call("createElement", "body").Get("classList")
+global.Get("document").Call("createElement", "body").Get("dataset")
+global.Get("document").Call("createElement", "body").Get("style")
+global.Get("document")
+global.Get("document").Get("readyState")
+global.Get("document").Set("body", jsObject(global.Get("document").Call("createElement", "body")))
+global.Call("requestAnimationFrame", func(float64))
+(expect body to be set now)
+global.Get("document").Call("createElement", "body").Get("classList")
+global.Get("document").Call("createElement", "body").Get("dataset")
+global.Get("document").Call("createElement", "body").Get("style")
+global.Get("document").Call("createElement", "body").Get("classList")
+global.Get("document").Call("createElement", "body").Get("dataset")
+global.Get("document").Call("createElement", "body").Get("style")
+global.Get("document")
+global.Get("document").Call("createElement", "div")
+global.Get("document").Call("createElement", "div").Get("classList")
+global.Get("document").Call("createElement", "div").Get("dataset")
+global.Get("document").Call("createElement", "div").Get("style")
+global.Get("document").Call("createElement", "body").Call("appendChild", jsObject(global.Get("document").Call("createElement", "div")))
+global.Call("requestAnimationFrame", func(float64))
\ No newline at end of file
diff --git a/testdata/TestRerender_identical.want.txt b/testdata/TestRerender_identical.want.txt
new file mode 100755
index 00000000..642de385
--- /dev/null
+++ b/testdata/TestRerender_identical.want.txt
@@ -0,0 +1,16 @@
+global.Get("document")
+global.Get("document").Call("createElement", "body")
+global.Get("document").Call("createElement", "body").Get("classList")
+global.Get("document").Call("createElement", "body").Get("dataset")
+global.Get("document").Call("createElement", "body").Get("style")
+global.Get("document")
+global.Get("document").Get("readyState")
+global.Get("document").Set("body", jsObject(global.Get("document").Call("createElement", "body")))
+global.Call("requestAnimationFrame", func(float64))
+global.Get("document").Call("createElement", "body").Get("classList")
+global.Get("document").Call("createElement", "body").Get("dataset")
+global.Get("document").Call("createElement", "body").Get("style")
+global.Get("document").Call("createElement", "body").Get("classList")
+global.Get("document").Call("createElement", "body").Get("dataset")
+global.Get("document").Call("createElement", "body").Get("style")
+global.Call("requestAnimationFrame", func(float64))
\ No newline at end of file
diff --git a/testdata/TestRerender_no_prevRender.want.txt b/testdata/TestRerender_no_prevRender.want.txt
new file mode 100644
index 00000000..e69de29b
diff --git a/testdata/TestSetTitle.want.txt b/testdata/TestSetTitle.want.txt
new file mode 100755
index 00000000..cfa05491
--- /dev/null
+++ b/testdata/TestSetTitle.want.txt
@@ -0,0 +1,2 @@
+global.Get("document")
+global.Get("document").Set("title", "foobartitle")
\ No newline at end of file
diff --git a/testsuite_test.go b/testsuite_test.go
new file mode 100644
index 00000000..daee16f0
--- /dev/null
+++ b/testsuite_test.go
@@ -0,0 +1,277 @@
+package vecty
+
+import (
+	"fmt"
+	"io/ioutil"
+	"os"
+	"os/exec"
+	"path"
+	"path/filepath"
+	"reflect"
+	"sort"
+	"strings"
+	"testing"
+)
+
+var _ = func() bool {
+	isTest = true
+	return true
+}()
+
+// recoverStr runs f and returns the recovered panic as a string.
+func recoverStr(f func()) (s string) {
+	defer func() {
+		s = fmt.Sprint(recover())
+	}()
+	f()
+	return
+}
+
+type componentFunc struct {
+	Core
+	id         string
+	render     func() ComponentOrHTML
+	skipRender func(prev Component) bool
+}
+
+func (c *componentFunc) Render() ComponentOrHTML        { return c.render() }
+func (c *componentFunc) SkipRender(prev Component) bool { return c.skipRender(prev) }
+
+func TestMain(m *testing.M) {
+	// Try to remove all testdata/*.got.txt files now.
+	matches, _ := filepath.Glob("testdata/*.got.txt")
+	for _, match := range matches {
+		os.Remove(match)
+	}
+
+	os.Exit(m.Run())
+}
+
+func testSuite(t *testing.T, testName string) *testSuiteT {
+	ts := &testSuiteT{
+		t:         t,
+		testName:  testName,
+		callbacks: make(map[string]interface{}),
+		strings:   &valueMocker{},
+		bools:     &valueMocker{},
+		floats:    &valueMocker{},
+		ints:      &valueMocker{},
+	}
+	global = &objectRecorder{
+		ts:   ts,
+		name: "global",
+	}
+	return ts
+}
+
+// mockedValue represents a mocked value.
+type mockedValue struct {
+	invocation string
+	value      interface{}
+}
+
+// valueMocker keeps tracked of mocked values for method invocations on
+// jsObject's.
+type valueMocker struct {
+	values []mockedValue
+}
+
+// mock adds an entry to mock the specified invocation to return the given
+// value.
+func (v *valueMocker) mock(invocation string, value interface{}) {
+	v.values = append(v.values, mockedValue{invocation, value})
+}
+
+// get gets the mocked value for the specified invocation.
+func (v *valueMocker) get(invocation string) interface{} {
+	for i, value := range v.values {
+		if value.invocation == invocation {
+			// Found the right invocation.
+			v.values = append(v.values[:i], v.values[i+1:]...)
+			return value.value
+		}
+	}
+	panic(fmt.Sprintf("expected mocked value for invocation: %s", invocation))
+}
+
+type testSuiteT struct {
+	t                            *testing.T
+	testName                     string
+	callbacks                    map[string]interface{}
+	strings, bools, floats, ints *valueMocker
+
+	got    string
+	isDone bool
+}
+
+func (ts *testSuiteT) done() {
+	ts.multiSortedDone()
+}
+
+// sortedDone is just like done(), except it sorts the specified line range first.
+func (ts *testSuiteT) sortedDone(sortStartLine, sortEndLine int) {
+	ts.multiSortedDone([2]int{sortStartLine, sortEndLine})
+}
+
+// multiSortedDone is just like done(), except it sorts the specified line range first.
+func (ts *testSuiteT) multiSortedDone(linesToSort ...[2]int) {
+	if ts.isDone {
+		panic("testSuite done methods called multiple times")
+	}
+	ts.isDone = true
+	// Read the want file or create it if it does not exist.
+	wantFileName := path.Join("testdata", ts.testName+".want.txt")
+	wantBytes, err := ioutil.ReadFile(wantFileName)
+	if err != nil {
+		if os.IsNotExist(err) {
+			// Touch the file
+			f, err := os.Create(wantFileName)
+			f.Close()
+			if err != nil {
+				ts.t.Fatal(err)
+			}
+		} else {
+			ts.t.Fatal(err)
+		}
+	}
+	want := strings.TrimSpace(string(wantBytes))
+
+	// Ensure output is properly sorted.
+	split := strings.Split(strings.TrimSpace(ts.got), "\n")
+	for _, pair := range linesToSort {
+		sortStartLine := pair[0] - 1 // to match editor line numbers
+		if sortStartLine < 0 {
+			sortStartLine = 0
+		}
+		sortEndLine := pair[1]
+		if sortEndLine > len(split) {
+			sortEndLine = len(split)
+		}
+		sorted := split[sortStartLine:sortEndLine]
+		ts.t.Logf("lines selected for sorting (%d-%d):\n%s\n\n", sortStartLine, sortEndLine, strings.Join(sorted, "\n"))
+		sort.Strings(sorted)
+		for i := sortStartLine; i < sortEndLine; i++ {
+			split[i] = sorted[i-sortStartLine]
+		}
+	}
+	got := strings.Join(split, "\n")
+
+	// Check if we got what we wanted.
+	if got == want {
+		// Successful test.
+
+		// Ensure there are no unused mocked values.
+		for _, v := range ts.strings.values {
+			ts.t.Errorf("unused mocked string value %q %v", v.invocation, v.value)
+		}
+		for _, v := range ts.bools.values {
+			ts.t.Errorf("unused mocked bool value %q %v", v.invocation, v.value)
+		}
+		for _, v := range ts.floats.values {
+			ts.t.Errorf("unused mocked float value %q %v", v.invocation, v.value)
+		}
+		for _, v := range ts.ints.values {
+			ts.t.Errorf("unused mocked int value %q %v", v.invocation, v.value)
+		}
+		return
+	}
+
+	// Write what we got to disk.
+	gotFileName := path.Join("testdata", ts.testName+".got.txt")
+	err = ioutil.WriteFile(gotFileName, []byte(got), 0777)
+	if err != nil {
+		ts.t.Fatal(err)
+	}
+
+	// Print a nice diff for easy comparison.
+	cmd := exec.Command("git", "-c", "color.ui=always", "diff", "--no-index", wantFileName, gotFileName)
+	out, _ := cmd.CombinedOutput()
+	ts.t.Log("\n" + string(out))
+
+	ts.t.Fatalf("to accept these changes:\n\n$ mv %s %s", gotFileName, wantFileName)
+}
+
+// record records the invocation to the test suite and returns the string
+// unmodified.
+func (ts *testSuiteT) record(invocation string) string {
+	ts.got += "\n" + invocation
+	return invocation
+}
+
+// addCallbacks adds the first function in args to ts.callbacks[invocation], if there is one.
+func (ts *testSuiteT) addCallbacks(invocation string, args ...interface{}) {
+	for _, a := range args {
+		if reflect.TypeOf(a).Kind() == reflect.Func {
+			ts.callbacks[invocation] = a
+			return
+		}
+	}
+}
+
+// objectRecorder implements the jsObject interface by recording method
+// invocations to the test suite.
+type objectRecorder struct {
+	ts   *testSuiteT
+	name string
+}
+
+// Set implements the jsObject interface.
+func (r *objectRecorder) Set(key string, value interface{}) {
+	invocation := r.ts.record(fmt.Sprintf("%s.Set(%q, %+v)", r.name, key, stringify(value)))
+	r.ts.addCallbacks(invocation, value)
+}
+
+// Get implements the jsObject interface.
+func (r *objectRecorder) Get(key string) jsObject {
+	invocation := r.ts.record(fmt.Sprintf("%s.Get(%q)", r.name, key))
+	return &objectRecorder{
+		ts:   r.ts,
+		name: invocation,
+	}
+}
+
+// Delete implements the jsObject interface.
+func (r *objectRecorder) Delete(key string) {
+	r.ts.record(fmt.Sprintf("%s.Delete(%q)", r.name, key))
+}
+
+// Call implements the jsObject interface.
+func (r *objectRecorder) Call(name string, args ...interface{}) jsObject {
+	invocation := r.ts.record(fmt.Sprintf("%s.Call(%q, %s)", r.name, name, stringify(args...)))
+	r.ts.addCallbacks(invocation, args...)
+	return &objectRecorder{
+		ts:   r.ts,
+		name: invocation,
+	}
+}
+
+// String implements the jsObject interface.
+func (r *objectRecorder) String() string { return r.ts.strings.get(r.name).(string) }
+
+// Bool implements the jsObject interface.
+func (r *objectRecorder) Bool() bool { return r.ts.bools.get(r.name).(bool) }
+
+// Int implements the jsObject interface.
+func (r *objectRecorder) Int() int { return r.ts.ints.get(r.name).(int) }
+
+// Float implements the jsObject interface.
+func (r *objectRecorder) Float() float64 { return r.ts.floats.get(r.name).(float64) }
+
+func stringify(args ...interface{}) string {
+	var s []string
+	for _, a := range args {
+		if reflect.TypeOf(a).Kind() == reflect.Func {
+			s = append(s, reflect.TypeOf(a).String())
+			continue
+		}
+		switch v := a.(type) {
+		case string:
+			s = append(s, fmt.Sprintf("%q", v))
+		case *objectRecorder:
+			s = append(s, fmt.Sprintf("jsObject(%s)", v.name))
+		default:
+			s = append(s, fmt.Sprintf("%v", v))
+		}
+	}
+	return strings.Join(s, ", ")
+}