internal/testing/integration: add test for duplicate symbols

An integration test is added for these cases:

- A symbol changes across different build contexts
- A symbol is introduced at different versions for different build contexts
- The package symbol for a symbol changes because its parent changes,
  but the name and synopsis are the same

For golang/go#37102

Change-Id: Ieca17042e11b2fd583e2133a3064ab6043a29858
Reviewed-on: https://go-review.googlesource.com/c/pkgsite/+/316969
Trust: Julie Qiu <[email protected]>
Run-TryBot: Julie Qiu <[email protected]>
Reviewed-by: Jonathan Amsterdam <[email protected]>

Author: julieqiu

internal/proxy/testdata/[email protected]

@@ -112,6 +112,7 @@ func HelloJS() string {
 
 package multigoos
 
+// Different signature from CloseOnExec for linux and darwin.
 func CloseOnExec(foo string) error {
     return nil
 }
@@ -121,6 +122,20 @@ func CloseOnExec(foo string) error {
 
 package multigoos
 
+// Different signature from CloseOnExec for windows.
 func CloseOnExec(num int) (int, error) {
     return num, nil
 }
+
+-- duplicate/duplicate.go --
+// +build linux darwin
+
+package duplicate
+
+// Unexported here, exported in v1.2.0.
+type tokenType int
+
+// Token types.
+const (
+	TokenShort tokenType = iota
+)

internal/proxy/testdata/[email protected]

@@ -129,3 +129,34 @@ package multigoos
 
 func CloseOnExec(n int) {
 }
+
+-- duplicate/duplicate.go --
+// +build linux darwin
+
+package duplicate
+
+type TokenType int
+
+// Token types.
+const (
+	TokenShort TokenType = iota
+)
+
+-- duplicate/duplicate_windows.go --
+// +build windows
+
+package duplicate
+
+// Constant here, type for JS, linux and darwin.
+const TokenType = 3
+
+-- duplicate/duplicate_js.go --
+// +build js
+
+package duplicate
+
+// Exported here, unexported in v1.1.0.
+type TokenType struct {
+}
+
+func TokenShort() TokenType { return &TokenType{} }

internal/testing/integration/data_frontend_versions_test.go

@@ -6,6 +6,93 @@ package integration
 
 import "golang.org/x/pkgsite/internal/frontend"
 
+var versionsPageMultiGoosDuplicates = []*frontend.VersionList{
+	{
+		VersionListKey: frontend.VersionListKey{
+			ModulePath: "example.com/symbols",
+			Major:      "v1",
+		},
+		Versions: []*frontend.VersionSummary{
+			{
+				CommitTime:          "Jan 30, 2019",
+				Link:                "/example.com/[email protected]/duplicate",
+				Retracted:           false,
+				RetractionRationale: "",
+				Version:             "v1.2.0",
+				IsMinor:             true,
+				Symbols: [][]*frontend.Symbol{
+					{
+						{
+							Name:     "TokenType",
+							Synopsis: "const TokenType",
+							Link:     "/example.com/[email protected]/duplicate?GOOS=windows#TokenType",
+							New:      true,
+							Section:  "Constants",
+							Kind:     "Constant",
+							Builds:   []string{"windows/amd64"},
+						},
+					},
+					{
+						{
+							Name:     "TokenType",
+							Synopsis: "type TokenType int",
+							Link:     "/example.com/[email protected]/duplicate?GOOS=darwin#TokenType",
+							New:      true,
+							Section:  "Types",
+							Kind:     "Type",
+							Builds:   []string{"darwin/amd64", "linux/amd64"},
+							// Children is nil because TokenShort was first
+							// introduced at an earlier version.
+							// Its parent and section changed at this version,
+							// but we don't surface that information.
+						},
+						{
+							Name:     "TokenType",
+							Synopsis: "type TokenType struct",
+							Link:     "/example.com/[email protected]/duplicate?GOOS=js#TokenType",
+							New:      true,
+							Section:  "Types",
+							Kind:     "Type",
+							Children: []*frontend.Symbol{
+								{
+									Name:     "TokenShort",
+									Synopsis: "func TokenShort() TokenType",
+									Link:     "/example.com/[email protected]/duplicate?GOOS=js#TokenShort",
+									New:      true,
+									Section:  "Types",
+									Kind:     "Function",
+								},
+							},
+							Builds: []string{"js/wasm"},
+						},
+					},
+				},
+			},
+			{
+				CommitTime:          "Jan 30, 2019",
+				Link:                "/example.com/[email protected]/duplicate",
+				Retracted:           false,
+				RetractionRationale: "",
+				Version:             "v1.1.0",
+				IsMinor:             true,
+				Symbols: [][]*frontend.Symbol{
+					{
+						{
+							Name:     "TokenShort",
+							Synopsis: "const TokenShort",
+							Link:     "/example.com/[email protected]/duplicate?GOOS=darwin#TokenShort",
+							New:      true,
+							Section:  "Constants",
+							Kind:     "Constant",
+							Builds:   []string{"darwin/amd64", "linux/amd64"},
+						},
+					},
+				},
+			},
+		},
+	},
+}
+
 var versionsPageMultiGoos = []*frontend.VersionList{
 	{
 		VersionListKey: frontend.VersionListKey{

internal/testing/integration/frontend_versions_test.go

@@ -52,7 +52,9 @@ func TestFrontendVersionsPage(t *testing.T) {
 			}{
 				{"versions page symbols - one version all symbols", modulePath, versionsPageSymbols},
 				{"versions page hello - multi GOOS", modulePath + "/hello", versionsPageHello},
-				{"versions page duplicate symbols multi GOOS", modulePath + "/multigoos", versionsPageMultiGoos},
+				{"versions page - test symbol signature is different for different build context", modulePath + "/multigoos", versionsPageMultiGoos},
+				{"versions page - test symbol is introduced at different versions for different build context and changes across versions",
+					modulePath + "/duplicate", versionsPageMultiGoosDuplicates},
 			} {
 				t.Run(test.name, func(t *testing.T) {
 					urlPath := fmt.Sprintf("/%s?tab=versions&m=json", test.pkgPath)