cmd/go: add some parallelism to the testsuite

As these tests were originally in bash, they are not designed to be
particularly hermetic.  This CL adds various protective mechanisms to
try to catch cases where the tests can not run in parallel.

Change-Id: I983bf7b6ffba04eda58b4939eb89b0bdfcda8eff
Reviewed-on: https://go-review.googlesource.com/10911Reviewed-by: Andrew Gerrand <adg@golang.org>

src/cmd/go/go_test.go

@@ -123,6 +123,7 @@ type testgoData struct {
 	env            []string
 	tempdir        string
 	ran            bool
+	inParallel     bool
 	stdout, stderr bytes.Buffer
 }
 
@@ -159,6 +160,26 @@ func (tg *testgoData) check(err error) {
 	}
 }
 
+// parallel runs the test in parallel by calling t.Parallel.
+func (tg *testgoData) parallel() {
+	if tg.ran {
+		tg.t.Fatal("internal testsuite error: call to parallel after run")
+	}
+	if tg.wd != "" {
+		tg.t.Fatal("internal testsuite error: call to parallel after cd")
+	}
+	for _, e := range tg.env {
+		if strings.HasPrefix(e, "GOROOT=") || strings.HasPrefix(e, "GOPATH=") || strings.HasPrefix(e, "GOBIN=") {
+			val := e[strings.Index(e, "=")+1:]
+			if strings.HasPrefix(val, "testdata") || strings.HasPrefix(val, "./testdata") {
+				tg.t.Fatalf("internal testsuite error: call to parallel with testdata in environment (%s)", e)
+			}
+		}
+	}
+	tg.inParallel = true
+	tg.t.Parallel()
+}
+
 // pwd returns the current directory.
 func (tg *testgoData) pwd() string {
 	wd, err := os.Getwd()
@@ -172,6 +193,9 @@ func (tg *testgoData) pwd() string {
 // using this means that the test must not be run in parallel with any
 // other tests.
 func (tg *testgoData) cd(dir string) {
+	if tg.inParallel {
+		tg.t.Fatal("internal testsuite error: changing directory when running in parallel")
+	}
 	if tg.wd == "" {
 		tg.wd = tg.pwd()
 	}
@@ -188,6 +212,9 @@ func (tg *testgoData) sleep() {
 // setenv sets an environment variable to use when running the test go
 // command.
 func (tg *testgoData) setenv(name, val string) {
+	if tg.inParallel && (name == "GOROOT" || name == "GOPATH" || name == "GOBIN") && (strings.HasPrefix(val, "testdata") || strings.HasPrefix(val, "./testdata")) {
+		tg.t.Fatalf("internal testsuite error: call to setenv with testdata (%s=%s) after parallel", name, val)
+	}
 	tg.unsetenv(name)
 	tg.env = append(tg.env, name+"="+val)
 }
@@ -211,6 +238,13 @@ func (tg *testgoData) doRun(args []string) error {
 	if !canRun {
 		panic("testgoData.doRun called but canRun false")
 	}
+	if tg.inParallel {
+		for _, arg := range args {
+			if strings.HasPrefix(arg, "testdata") || strings.HasPrefix(arg, "./testdata") {
+				tg.t.Fatal("internal testsuite error: parallel run using testdata")
+			}
+		}
+	}
 	tg.t.Logf("running testgo %v", args)
 	var prog string
 	if tg.wd == "" {
@@ -502,6 +536,7 @@ func (tg *testgoData) cleanup() {
 func TestFileLineInErrorMessages(t *testing.T) {
 	tg := testgo(t)
 	defer tg.cleanup()
+	tg.parallel()
 	tg.tempFile("err.go", `package main; import "bar"`)
 	path := tg.path("err.go")
 	tg.runFail("run", path)
@@ -511,6 +546,7 @@ func TestFileLineInErrorMessages(t *testing.T) {
 func TestProgramNameInCrashMessages(t *testing.T) {
 	tg := testgo(t)
 	defer tg.cleanup()
+	tg.parallel()
 	tg.tempFile("triv.go", `package main; func main() {}`)
 	tg.runFail("build", "-ldflags", "-crash_for_testing", tg.path("triv.go"))
 	tg.grepStderr(`[/\\]tool[/\\].*[/\\]link`, "missing linker name in error message")
@@ -527,6 +563,10 @@ func TestBrokenTestsWithoutTestFunctionsAllFail(t *testing.T) {
 }
 
 func TestGoBuildDashAInDevBranch(t *testing.T) {
+	if testing.Short() {
+		t.Skip("don't rebuild the standard library in short mode")
+	}
+
 	tg := testgo(t)
 	defer tg.cleanup()
 	tg.run("install", "math") // should be up to date already but just in case
@@ -537,7 +577,7 @@ func TestGoBuildDashAInDevBranch(t *testing.T) {
 
 func TestGoBuilDashAInReleaseBranch(t *testing.T) {
 	if testing.Short() {
-		t.Skip("don't rebuild the standard libary in short mode")
+		t.Skip("don't rebuild the standard library in short mode")
 	}
 
 	tg := testgo(t)
@@ -596,6 +636,7 @@ func TestGoInstallCleansUpAfterGoBuild(t *testing.T) {
 func TestGoInstallRebuildsStalePackagesInOtherGOPATH(t *testing.T) {
 	tg := testgo(t)
 	defer tg.cleanup()
+	tg.parallel()
 	tg.tempFile("d1/src/p1/p1.go", `package p1
 
 import "p2"
@@ -630,6 +671,7 @@ func F() {}
 func TestGoInstallDetectsRemovedFiles(t *testing.T) {
 	tg := testgo(t)
 	defer tg.cleanup()
+	tg.parallel()
 	tg.tempFile("src/mypkg/x.go", `package mypkg`)
 	tg.tempFile("src/mypkg/y.go", `package mypkg`)
 	tg.tempFile("src/mypkg/z.go", `// +build missingtag
@@ -649,6 +691,7 @@ package mypkg`)
 func TestGoInstsallDetectsRemovedFilesInPackageMain(t *testing.T) {
 	tg := testgo(t)
 	defer tg.cleanup()
+	tg.parallel()
 	tg.tempFile("src/mycmd/x.go", `package main
 
 func main() {}
@@ -801,6 +844,7 @@ func testMove(t *testing.T, vcs, url, base, config string) {
 	}
 	tg := testgo(t)
 	defer tg.cleanup()
+	tg.parallel()
 	tg.tempDir("src")
 	tg.setenv("GOPATH", tg.path("."))
 	tg.run("get", "-d", url)
@@ -1014,6 +1058,7 @@ func TestGodocInstalls(t *testing.T) {
 	// godoc installs into GOBIN
 	tg := testgo(t)
 	defer tg.cleanup()
+	tg.parallel()
 	tg.tempDir("gobin")
 	tg.setenv("GOPATH", tg.path("."))
 	tg.setenv("GOBIN", tg.path("gobin"))
@@ -1032,6 +1077,7 @@ func TestGodocInstalls(t *testing.T) {
 func TestInstalls(t *testing.T) {
 	tg := testgo(t)
 	defer tg.cleanup()
+	tg.parallel()
 	tg.tempDir("gobin")
 	tg.setenv("GOPATH", tg.path("."))
 	goroot := runtime.GOROOT()
@@ -1206,6 +1252,7 @@ func TestWithoutGOPATHGoGetFails(t *testing.T) {
 
 	tg := testgo(t)
 	defer tg.cleanup()
+	tg.parallel()
 	tg.tempDir("src")
 	tg.setenv("GOPATH", "")
 	tg.setenv("GOROOT", tg.path("."))
@@ -1220,6 +1267,7 @@ func TestWithGOPATHEqualsGOROOTGoGetFails(t *testing.T) {
 
 	tg := testgo(t)
 	defer tg.cleanup()
+	tg.parallel()
 	tg.tempDir("src")
 	tg.setenv("GOPATH", tg.path("."))
 	tg.setenv("GOROOT", tg.path("."))
@@ -1229,6 +1277,7 @@ func TestWithGOPATHEqualsGOROOTGoGetFails(t *testing.T) {
 func TestLdflagsArgumentsWithSpacesIssue3941(t *testing.T) {
 	tg := testgo(t)
 	defer tg.cleanup()
+	tg.parallel()
 	tg.tempFile("main.go", `package main
 var extern string
 func main() {
@@ -1296,6 +1345,7 @@ func TestSymlinksDoNotConfuseGoList(t *testing.T) {
 func TestInstallWithTags(t *testing.T) {
 	tg := testgo(t)
 	defer tg.cleanup()
+	tg.parallel()
 	tg.tempDir("bin")
 	tg.tempFile("src/example/a/main.go", `package main
 func main() {}`)
@@ -1322,6 +1372,7 @@ func main() {}`)
 func TestCaseCollisions(t *testing.T) {
 	tg := testgo(t)
 	defer tg.cleanup()
+	tg.parallel()
 	tg.tempDir("src/example/a/pkg")
 	tg.tempDir("src/example/a/Pkg")
 	tg.tempDir("src/example/b")
@@ -1362,6 +1413,7 @@ func TestGoGetDashTIssue8181(t *testing.T) {
 
 	tg := testgo(t)
 	defer tg.cleanup()
+	tg.parallel()
 	tg.makeTempdir()
 	tg.setenv("GOPATH", tg.path("."))
 	tg.run("get", "-t", "code.google.com/p/go-get-issue-8181/a", "code.google.com/p/go-get-issue-8181/b")
@@ -1551,6 +1603,7 @@ func TestCgoShowsFullPathNames(t *testing.T) {
 
 	tg := testgo(t)
 	defer tg.cleanup()
+	tg.parallel()
 	tg.tempFile("src/x/y/dirname/foo.go", `
 package foo
 import "C"
@@ -1567,6 +1620,7 @@ func TestCgoHandlesWlORIGIN(t *testing.T) {
 
 	tg := testgo(t)
 	defer tg.cleanup()
+	tg.parallel()
 	tg.tempFile("src/origin/origin.go", `package origin
 // #cgo !darwin LDFLAGS: -Wl,-rpath -Wl,$ORIGIN
 // void f(void) {}
@@ -1593,6 +1647,7 @@ func TestIssue7573(t *testing.T) {
 
 	tg := testgo(t)
 	defer tg.cleanup()
+	tg.parallel()
 	tg.tempFile("src/cgoref/cgoref.go", `
 package main
 // #cgo LDFLAGS: -L alibpath -lalib
@@ -1635,6 +1690,7 @@ func TestIssue6844(t *testing.T) {
 func TestBuildDashIInstallsDependencies(t *testing.T) {
 	tg := testgo(t)
 	defer tg.cleanup()
+	tg.parallel()
 	tg.tempFile("src/x/y/foo/foo.go", `package foo
 func F() {}`)
 	tg.tempFile("src/x/y/bar/bar.go", `package bar