internal/godoc/dochtml: compare with golden

Add a comparison with a golden file to the test, for
more thorough coverage.

Delete tests that are obsoleted by having a golden.

Factor out golden comparison to a separate package.

For golang/go#40850

Change-Id: Iac7b4c0e1c4aadad690d8d5118a6861408614aa2
Reviewed-on: https://go-review.googlesource.com/c/pkgsite/+/313030
Trust: Jonathan Amsterdam <jba@google.com>
Run-TryBot: Jonathan Amsterdam <jba@google.com>
Reviewed-by: Jamal Carvalho <jamal@golang.org>

internal/godoc/codec/generate_test.go

@@ -10,12 +10,11 @@ import (
 	"go/ast"
 	"go/token"
 	"io"
-	"io/ioutil"
-	"path/filepath"
 	"reflect"
 	"testing"
 
 	"github.com/google/go-cmp/cmp"
+	"golang.org/x/pkgsite/internal/testing/testhelper"
 )
 
 var update = flag.Bool("update", false, "update goldens instead of checking against them")
@@ -57,30 +56,7 @@ func testGenerate(t *testing.T, name string, x interface{}) {
 		t.Fatal(err)
 	}
 	got := buf.String()
-	if *update {
-		writeGolden(t, name, got)
-	} else {
-		want := readGolden(t, name)
-		if diff := cmp.Diff(want, got); diff != "" {
-			t.Errorf("%s: mismatch (-want, +got):\n%s", name, diff)
-		}
-	}
-}
-
-func writeGolden(t *testing.T, name string, data string) {
-	filename := filepath.Join("testdata", name+".go")
-	if err := ioutil.WriteFile(filename, []byte(data), 0644); err != nil {
-		t.Fatal(err)
-	}
-	t.Logf("wrote %s", filename)
-}
-
-func readGolden(t *testing.T, name string) string {
-	data, err := ioutil.ReadFile(filepath.Join("testdata", name+".go"))
-	if err != nil {
-		t.Fatal(err)
-	}
-	return string(data)
+	testhelper.CompareWithGolden(t, got, name+".go", *update)
 }
 
 func TestExportedFields(t *testing.T) {

internal/godoc/dochtml/dochtml_test.go

@@ -7,6 +7,9 @@ package dochtml
 import (
 	"bytes"
 	"context"
+	"flag"
+	"fmt"
+
 	"go/ast"
 	"go/parser"
 	"go/token"
@@ -22,10 +25,13 @@ import (
 	"golang.org/x/pkgsite/internal/godoc/dochtml/internal/render"
 	"golang.org/x/pkgsite/internal/godoc/internal/doc"
 	"golang.org/x/pkgsite/internal/testing/htmlcheck"
+	"golang.org/x/pkgsite/internal/testing/testhelper"
 )
 
 var templateSource = template.TrustedSourceFromConstant("../../../content/static/html/doc")
 
+var update = flag.Bool("update", false, "update goldens instead of checking against them")
+
 var (
 	in           = htmlcheck.In
 	hasAttr      = htmlcheck.HasAttr
@@ -41,27 +47,28 @@ var testRenderOptions = RenderOptions{
 }
 
 func TestRenderParts(t *testing.T) {
+	ctx := context.Background()
 	LoadTemplates(templateSource)
-	fset, d := mustLoadPackage("everydecl")
 
-	ctx := context.Background()
+	fset, d := mustLoadPackage("everydecl")
 	parts, err := Render(ctx, fset, d, testRenderOptions)
 	if err != nil {
 		t.Fatal(err)
 	}
-	bodyDoc, err := html.Parse(strings.NewReader(parts.Body.String()))
-	if err != nil {
-		t.Fatal(err)
-	}
+	compareWithGolden(t, parts, "everydecl", *update)
 
-	sidenavDoc, err := html.Parse(strings.NewReader(parts.Outline.String()))
+	fset2, d2 := mustLoadPackage("deprecated")
+	parts2, err := Render(ctx, fset2, d2, testRenderOptions)
 	if err != nil {
 		t.Fatal(err)
 	}
-	mobileDoc, err := html.Parse(strings.NewReader(parts.MobileOutline.String()))
+	compareWithGolden(t, parts2, "deprecated", *update)
+
+	bodyDoc, err := html.Parse(strings.NewReader(parts.Body.String()))
 	if err != nil {
 		t.Fatal(err)
 	}
+
 	// Check that there are no duplicate id attributes.
 	t.Run("duplicate ids", func(t *testing.T) {
 		testDuplicateIDs(t, bodyDoc)
@@ -71,31 +78,6 @@ func TestRenderParts(t *testing.T) {
 		testIDsAndKinds(t, bodyDoc)
 	})
 
-	checker := in(".Documentation-note",
-		in("h3", hasAttr("id", "pkg-note-BUG"), hasExactText("Bugs ¶")),
-		in("a", hasHref("#pkg-note-BUG")))
-	if err := checker(bodyDoc); err != nil {
-		t.Errorf("note check: %v", err)
-	}
-
-	checker = in(".Documentation-index",
-		in(".Documentation-indexNote", in("a", hasHref("#pkg-note-BUG"), hasExactText("Bugs"))))
-	if err := checker(bodyDoc); err != nil {
-		t.Errorf("note check: %v", err)
-	}
-
-	checker = in(".DocNav-notes",
-		in("#nav-group-notes", in("li", in("a", hasHref("#pkg-note-BUG"), hasText("Bugs")))))
-	if err := checker(sidenavDoc); err != nil {
-		t.Errorf("note check: %v", err)
-	}
-
-	checker = in("",
-		in("optgroup[label=Notes]", in("option", hasAttr("value", "pkg-note-BUG"), hasExactText("Bugs"))))
-	if err := checker(mobileDoc); err != nil {
-		t.Errorf("note check: %v", err)
-	}
-
 	wantLinks := []render.Link{
 		{Href: "https://go.googlesource.com/pkgsite", Text: "pkgsite repo"},
 		{Href: "https://play-with-go.dev", Text: "Play with Go"},
@@ -105,6 +87,11 @@ func TestRenderParts(t *testing.T) {
 	}
 }
 
+func compareWithGolden(t *testing.T, parts *Parts, name string, update bool) {
+	got := fmt.Sprintf("%s\n----\n%s\n----\n%s\n", parts.Body, parts.Outline, parts.MobileOutline)
+	testhelper.CompareWithGolden(t, got, name+".golden", update)
+}
+
 func TestExampleRender(t *testing.T) {
 	LoadTemplates(templateSource)
 	ctx := context.Background()
@@ -353,33 +340,6 @@ func TestVersionedPkgPath(t *testing.T) {
 	}
 }
 
-func TestDeprecated(t *testing.T) {
-	LoadTemplates(templateSource)
-	ctx := context.Background()
-	fset, d := mustLoadPackage("deprecated")
-	parts, err := Render(ctx, fset, d, testRenderOptions)
-	if err != nil {
-		t.Fatal(err)
-	}
-	// In package deprecated, all non-deprecated symbols begin with "Good" and
-	// all deprecated ones begin with "Bad".
-	// There is one const, var, func and type of each.
-
-	// The outline only has functions and types, so we should see two "Good"s and no "Bad"s.
-	outlineString := parts.Outline.String()
-	for _, want := range []string{"GoodF()", "type GoodT", "GoodM", "NewGoodTGood()"} {
-		if !strings.Contains(outlineString, want) {
-			t.Errorf("outline does not have %q but should", want)
-		}
-	}
-	for _, notWant := range []string{"BadF()", "type BadT", "BadM()", "NewGoodTBad()"} {
-		if strings.Contains(outlineString, notWant) {
-			t.Errorf("outline has %q but shouldn't", notWant)
-		}
-	}
-
-}
-
 func testDuplicateIDs(t *testing.T, htmlDoc *html.Node) {
 	idCounts := map[string]int{}
 	walk(htmlDoc, func(n *html.Node) {