x/pkgsite: add tests cases for fetch.FetchModule

Fixes golang/go#40109

Change-Id: Id065d436b4605473e47cfc98b8cf95a096bad126
Reviewed-on: https://go-review.googlesource.com/c/pkgsite/+/247577
Run-TryBot: Julie Qiu <julie@golang.org>
TryBot-Result: kokoro <noreply+kokoro@google.com>
Reviewed-by: Jonathan Amsterdam <jba@google.com>
Reviewed-by: Julie Qiu <julie@golang.org>

internal/fetch/fetch_test.go

@@ -49,8 +49,9 @@ func TestFetchModule(t *testing.T) {
 	MaxDocumentationHTML = 1 * megabyte
 
 	for _, test := range []struct {
-		name string
-		mod  *testModule
+		name         string
+		mod          *testModule
+		fetchVersion string
 	}{
 		{name: "basic", mod: moduleNoGoMod},
 		{name: "wasm", mod: moduleWasm},
@@ -67,6 +68,8 @@ func TestFetchModule(t *testing.T) {
 		{name: "module with method example", mod: moduleMethodExample},
 		{name: "module with nonredistributable packages", mod: moduleNonRedist},
 		{name: "stdlib module", mod: moduleStd},
+		{name: "master version of module", mod: moduleMaster, fetchVersion: "master"},
+		{name: "latest version of module", mod: moduleLatest, fetchVersion: "latest"},
 	} {
 		t.Run(test.name, func(t *testing.T) {
 			ctx := experiment.NewContext(context.Background(), internal.ExperimentExecutableExamples)
@@ -75,9 +78,13 @@ func TestFetchModule(t *testing.T) {
 
 			modulePath := test.mod.mod.ModulePath
 			version := test.mod.mod.Version
+			fetchVersion := test.fetchVersion
 			if version == "" {
 				version = "v1.0.0"
 			}
+			if fetchVersion == "" {
+				fetchVersion = version
+			}
 			sourceClient := source.NewClient(sourceTimeout)
 			proxyClient, teardownProxy := proxy.SetupTestClient(t, []*proxy.Module{{
 				ModulePath: modulePath,
@@ -85,11 +92,11 @@ func TestFetchModule(t *testing.T) {
 				Files:      test.mod.mod.Files,
 			}})
 			defer teardownProxy()
-			got := FetchModule(ctx, modulePath, version, proxyClient, sourceClient)
+			got := FetchModule(ctx, modulePath, fetchVersion, proxyClient, sourceClient)
 			if got.Error != nil {
 				t.Fatal(got.Error)
 			}
-			d := licenseDetector(ctx, t, modulePath, version, proxyClient)
+			d := licenseDetector(ctx, t, modulePath, fetchVersion, proxyClient)
 			fr := cleanFetchResult(test.mod.fr, d)
 			sortFetchResult(fr)
 			sortFetchResult(got)

internal/fetch/fetchdata_test.go

@@ -865,6 +865,91 @@ var moduleStd = &testModule{
 	},
 }
 
+var moduleMaster = &testModule{
+	mod: &proxy.Module{
+		ModulePath: "github.com/my/module",
+		Files: map[string]string{
+			"foo/foo.go": "// package foo exports a helpful constant.\npackage foo\nconst Bar = 1",
+		},
+		Version: "v0.0.0-20200706064627-355bc3f705ed",
+	},
+	fr: &FetchResult{
+		RequestedVersion: "master",
+		Module: &internal.Module{
+			LegacyModuleInfo: internal.LegacyModuleInfo{
+				ModuleInfo: internal.ModuleInfo{
+					ModulePath:  "github.com/my/module",
+					Version:     "v0.0.0-20200706064627-355bc3f705ed",
+					VersionType: "pseudo",
+					SourceInfo:  source.NewGitHubInfo("https://github.com/my/module", "", "355bc3f705ed"),
+				},
+			},
+			Directories: []*internal.Directory{
+				{
+					DirectoryMeta: internal.DirectoryMeta{
+						Path:   "github.com/my/module",
+						V1Path: "github.com/my/module",
+					},
+				},
+				{
+					DirectoryMeta: internal.DirectoryMeta{
+						Path:   "github.com/my/module/foo",
+						V1Path: "github.com/my/module/foo",
+					},
+					Package: &internal.Package{
+						Name: "foo",
+						Documentation: &internal.Documentation{
+							Synopsis: "package foo exports a helpful constant.",
+						},
+					},
+				},
+			},
+		},
+	},
+}
+
+var moduleLatest = &testModule{
+	mod: &proxy.Module{
+		ModulePath: "github.com/my/module",
+		Files: map[string]string{
+			"foo/foo.go": "// package foo exports a helpful constant.\npackage foo\nconst Bar = 1",
+		},
+		Version: "v1.2.4",
+	},
+	fr: &FetchResult{
+		RequestedVersion: "latest",
+		Module: &internal.Module{
+			LegacyModuleInfo: internal.LegacyModuleInfo{
+				ModuleInfo: internal.ModuleInfo{
+					ModulePath: "github.com/my/module",
+					Version:    "v1.2.4",
+					SourceInfo: source.NewGitHubInfo("https://github.com/my/module", "", "v1.2.4"),
+				},
+			},
+			Directories: []*internal.Directory{
+				{
+					DirectoryMeta: internal.DirectoryMeta{
+						Path:   "github.com/my/module",
+						V1Path: "github.com/my/module",
+					},
+				},
+				{
+					DirectoryMeta: internal.DirectoryMeta{
+						Path:   "github.com/my/module/foo",
+						V1Path: "github.com/my/module/foo",
+					},
+					Package: &internal.Package{
+						Name: "foo",
+						Documentation: &internal.Documentation{
+							Synopsis: "package foo exports a helpful constant.",
+						},
+					},
+				},
+			},
+		},
+	},
+}
+
 // moduleWithExamples returns a testModule that contains an example.
 // It provides the common bits for the tests for package, function,
 // type, and method examples below.

internal/fetch/test_helper.go

@@ -36,7 +36,9 @@ func cleanFetchResult(fr *FetchResult, detector *licenses.Detector) *FetchResult
 	if fr.Module.Version == "" {
 		fr.Module.Version = "v1.0.0"
 	}
-	fr.RequestedVersion = fr.Module.Version
+	if fr.RequestedVersion == "" {
+		fr.RequestedVersion = fr.Module.Version
+	}
 	fr.ResolvedVersion = fr.Module.Version
 	if fr.Module.VersionType == "" {
 		fr.Module.VersionType = version.TypeRelease