Update tests to use cmp.Diff instead of reflect.DeepEqual (#1244)

language/go/BUILD.bazel

@@ -78,6 +78,7 @@ go_test(
         "//testtools",
         "//walk",
         "@com_github_bazelbuild_buildtools//build:go_default_library",
+        "@com_github_google_go_cmp//cmp",
         "@org_golang_x_tools//go/vcs",
     ],
 )

language/go/config_test.go

@@ -18,7 +18,6 @@ package golang
 import (
 	"path"
 	"path/filepath"
-	"reflect"
 	"strings"
 	"testing"
 
@@ -29,6 +28,7 @@ import (
 	"github.com/bazelbuild/bazel-gazelle/rule"
 	"github.com/bazelbuild/bazel-gazelle/testtools"
 	"github.com/bazelbuild/bazel-gazelle/walk"
+	"github.com/google/go-cmp/cmp"
 )
 
 func testConfig(t *testing.T, args ...string) (*config.Config, []language.Language, []config.Configurer) {
@@ -121,14 +121,15 @@ func TestDirectives(t *testing.T) {
 	if !gc.goGrpcCompilersSet {
 		t.Error("expected goGrpcCompilersSet to be set")
 	}
-	if !reflect.DeepEqual(gc.goGrpcCompilers, []string{"abc", "def"}) {
-		t.Errorf("got goGrpcCompilers %v; want [abc def]", gc.goGrpcCompilers)
+	if diff := cmp.Diff([]string{"abc", "def"}, gc.goGrpcCompilers); diff != "" {
+		t.Errorf("(-want, +got): %s", diff)
 	}
+
 	if !gc.goProtoCompilersSet {
 		t.Error("expected goProtoCompilersSet to be set")
 	}
-	if !reflect.DeepEqual(gc.goProtoCompilers, []string{"foo", "bar"}) {
-		t.Errorf("got goProtoCompilers %v; want [foo bar]", gc.goProtoCompilers)
+	if diff := cmp.Diff(gc.goProtoCompilers, []string{"foo", "bar"}); diff != "" {
+		t.Errorf("(-want, +got): %s", diff)
 	}
 
 	subContent := []byte(`
@@ -146,15 +147,17 @@ func TestDirectives(t *testing.T) {
 	if gc.goGrpcCompilersSet {
 		t.Error("expected goGrpcCompilersSet to be unset")
 	}
-	if !reflect.DeepEqual(gc.goGrpcCompilers, defaultGoGrpcCompilers) {
-		t.Errorf("got goGrpcCompilers %v; want %v", gc.goGrpcCompilers, defaultGoGrpcCompilers)
+	if diff := cmp.Diff(defaultGoGrpcCompilers, gc.goGrpcCompilers); diff != "" {
+		t.Errorf("(-want, +got): %s", diff)
 	}
+
 	if gc.goProtoCompilersSet {
 		t.Error("expected goProtoCompilersSet to be unset")
 	}
-	if !reflect.DeepEqual(gc.goProtoCompilers, defaultGoProtoCompilers) {
-		t.Errorf("got goProtoCompilers %v; want %v", gc.goProtoCompilers, defaultGoProtoCompilers)
+	if diff := cmp.Diff(defaultGoProtoCompilers, gc.goProtoCompilers); diff != "" {
+		t.Errorf("(-want, +got): %s", diff)
 	}
+
 }
 
 func TestVendorConfig(t *testing.T) {
@@ -340,8 +343,9 @@ func TestSplitValue(t *testing.T) {
 		},
 	} {
 		parts := splitValue(tc.value)
-		if !reflect.DeepEqual(tc.parts, parts) {
-			t.Errorf("want %v; got %v", tc.parts, parts)
+		if diff := cmp.Diff(tc.parts, parts); diff != "" {
+			t.Errorf("(-want, +got): %s", diff)
 		}
+
 	}
 }

language/go/fileinfo_go_test.go

@@ -19,9 +19,18 @@ import (
 	"io/ioutil"
 	"os"
 	"path/filepath"
-	"reflect"
 	"strings"
 	"testing"
+
+	"github.com/google/go-cmp/cmp"
+)
+
+var (
+	fileInfoCmpOption = cmp.AllowUnexported(
+		fileInfo{},
+		fileEmbed{},
+		taggedOpts{},
+	)
 )
 
 func TestGoFileInfo(t *testing.T) {
@@ -178,9 +187,10 @@ var src string
 				got.embeds[i] = fileEmbed{path: got.embeds[i].path}
 			}
 
-			if !reflect.DeepEqual(got, tc.want) {
-				t.Errorf("case %q: got %#v; want %#v", tc.desc, got, tc.want)
+			if diff := cmp.Diff(tc.want, got, fileInfoCmpOption); diff != "" {
+				t.Errorf("(-want, +got): %s", diff)
 			}
+
 		})
 	}
 }
@@ -205,9 +215,10 @@ func TestGoFileInfoFailure(t *testing.T) {
 		goos:   "linux",
 		goarch: "amd64",
 	}
-	if !reflect.DeepEqual(got, want) {
-		t.Errorf("got %#v ; want %#v", got, want)
+	if diff := cmp.Diff(want, got, fileInfoCmpOption); diff != "" {
+		t.Errorf("(-want, +got): %s", diff)
 	}
+
 }
 
 func TestCgo(t *testing.T) {
@@ -331,9 +342,10 @@ import ("C")
 				clinkopts: got.clinkopts,
 			}
 
-			if !reflect.DeepEqual(got, tc.want) {
-				t.Errorf("case %q: got %#v; want %#v", tc.desc, got, tc.want)
+			if diff := cmp.Diff(tc.want, got, fileInfoCmpOption); diff != "" {
+				t.Errorf("(-want, +got): %s", diff)
 			}
+
 		})
 	}
 }
@@ -371,6 +383,16 @@ func TestExpandSrcDir(t *testing.T) {
 	}
 }
 
+var (
+	goPackageCmpOption = cmp.AllowUnexported(
+		goPackage{},
+		goTarget{},
+		protoTarget{},
+		platformStringsBuilder{},
+		platformStringInfo{},
+	)
+)
+
 func TestExpandSrcDirRepoRelative(t *testing.T) {
 	repo, err := ioutil.TempDir(os.Getenv("TEST_TEMPDIR"), "repo")
 	if err != nil {
@@ -409,9 +431,10 @@ import "C"
 	}
 	want.library.sources.addGenericString("sub.go")
 	want.library.copts.addGenericString("-Isub/..")
-	if !reflect.DeepEqual(got, want) {
-		t.Errorf("got %#v ; want %#v", got, want)
+	if diff := cmp.Diff(want, got, goPackageCmpOption); diff != "" {
+		t.Errorf("(-want, +got): %s", diff)
 	}
+
 }
 
 // Copied from go/build build_test.go

language/go/fileinfo_test.go

@@ -21,6 +21,8 @@ import (
 	"path/filepath"
 	"reflect"
 	"testing"
+
+	"github.com/google/go-cmp/cmp"
 )
 
 func TestOtherFileInfo(t *testing.T) {
@@ -55,9 +57,10 @@ func TestOtherFileInfo(t *testing.T) {
 
 			// Only check that we can extract tags. Everything else is covered
 			// by other tests.
-			if !reflect.DeepEqual(got.tags, tc.wantTags) {
-				t.Errorf("got %#v; want %#v", got.tags, tc.wantTags)
+			if diff := cmp.Diff(tc.wantTags, got.tags, fileInfoCmpOption); diff != "" {
+				t.Errorf("(-want, +got): %s", diff)
 			}
+
 		})
 	}
 }
@@ -331,8 +334,8 @@ package main`,
 
 		if got, err := readTags(path); err != nil {
 			t.Fatal(err)
-		} else if !reflect.DeepEqual(got, tc.want) {
-			t.Errorf("case %q: got %#v; want %#v", tc.desc, got, tc.want)
+		} else if diff := cmp.Diff(tc.want, got); diff != "" {
+			t.Errorf("(-want, +got): %s", diff)
 		}
 	}
 }