all: make tests able to run multiple times.

It is now possible to run "go test -cpu=1,2,4 std"
successfully.

Fixes #3185.

R=golang-dev, dave, minux.ma, bradfitz
CC=golang-dev
https://golang.org/cl/7196052

src/pkg/debug/gosym/pclntab_test.go

@@ -52,6 +52,14 @@ func dotest() bool {
 	return true
 }
 
+func endtest() {
+	if pclineTempDir != "" {
+		os.RemoveAll(pclineTempDir)
+		pclineTempDir = ""
+		pclinetestBinary = ""
+	}
+}
+
 func getTable(t *testing.T) *Table {
 	f, tab := crack(os.Args[0], t)
 	f.Close()
@@ -95,6 +103,7 @@ func TestLineFromAline(t *testing.T) {
 	if !dotest() {
 		return
 	}
+	defer endtest()
 
 	tab := getTable(t)
 
@@ -142,6 +151,7 @@ func TestLineAline(t *testing.T) {
 	if !dotest() {
 		return
 	}
+	defer endtest()
 
 	tab := getTable(t)
 
@@ -183,7 +193,7 @@ func TestPCLine(t *testing.T) {
 	if !dotest() {
 		return
 	}
-	defer os.RemoveAll(pclineTempDir)
+	defer endtest()
 
 	f, tab := crack(pclinetestBinary, t)
 	text := f.Section(".text")

src/pkg/exp/locale/collate/build/builder_test.go

@@ -89,7 +89,10 @@ var convLargeTests = []convertTest{
 
 func TestConvertLarge(t *testing.T) {
 	for i, tt := range convLargeTests {
-		e := &entry{elems: tt.in}
+		e := new(entry)
+		for _, ce := range tt.in {
+			e.elems = append(e.elems, makeRawCE(ce.w, ce.ccc))
+		}
 		elems, err := convertLargeWeights(e.elems)
 		if tt.err {
 			if err == nil {

src/pkg/expvar/expvar_test.go

@@ -18,6 +18,7 @@ func RemoveAll() {
 }
 
 func TestInt(t *testing.T) {
+	RemoveAll()
 	reqs := NewInt("requests")
 	if reqs.i != 0 {
 		t.Errorf("reqs.i = %v, want 0", reqs.i)
@@ -43,6 +44,7 @@ func TestInt(t *testing.T) {
 }
 
 func TestFloat(t *testing.T) {
+	RemoveAll()
 	reqs := NewFloat("requests-float")
 	if reqs.f != 0.0 {
 		t.Errorf("reqs.f = %v, want 0", reqs.f)
@@ -68,6 +70,7 @@ func TestFloat(t *testing.T) {
 }
 
 func TestString(t *testing.T) {
+	RemoveAll()
 	name := NewString("my-name")
 	if name.s != "" {
 		t.Errorf("name.s = %q, want \"\"", name.s)
@@ -84,6 +87,7 @@ func TestString(t *testing.T) {
 }
 
 func TestMapCounter(t *testing.T) {
+	RemoveAll()
 	colors := NewMap("bike-shed-colors")
 
 	colors.Add("red", 1)
@@ -123,6 +127,7 @@ func TestMapCounter(t *testing.T) {
 }
 
 func TestFunc(t *testing.T) {
+	RemoveAll()
 	var x interface{} = []string{"a", "b"}
 	f := Func(func() interface{} { return x })
 	if s, exp := f.String(), `["a","b"]`; s != exp {

src/pkg/flag/flag_test.go

@@ -15,17 +15,6 @@ import (
 	"time"
 )
 
-var (
-	test_bool     = Bool("test_bool", false, "bool value")
-	test_int      = Int("test_int", 0, "int value")
-	test_int64    = Int64("test_int64", 0, "int64 value")
-	test_uint     = Uint("test_uint", 0, "uint value")
-	test_uint64   = Uint64("test_uint64", 0, "uint64 value")
-	test_string   = String("test_string", "0", "string value")
-	test_float64  = Float64("test_float64", 0, "float64 value")
-	test_duration = Duration("test_duration", 0, "time.Duration value")
-)
-
 func boolString(s string) string {
 	if s == "0" {
 		return "false"
@@ -34,6 +23,16 @@ func boolString(s string) string {
 }
 
 func TestEverything(t *testing.T) {
+	ResetForTesting(nil)
+	Bool("test_bool", false, "bool value")
+	Int("test_int", 0, "int value")
+	Int64("test_int64", 0, "int64 value")
+	Uint("test_uint", 0, "uint value")
+	Uint64("test_uint64", 0, "uint64 value")
+	String("test_string", "0", "string value")
+	Float64("test_float64", 0, "float64 value")
+	Duration("test_duration", 0, "time.Duration value")
+
 	m := make(map[string]*Flag)
 	desired := "0"
 	visitor := func(f *Flag) {

src/pkg/go/parser/error_test.go

@@ -34,9 +34,11 @@ import (
 
 const testdata = "testdata"
 
+var fsetErrs *token.FileSet
+
 // getFile assumes that each filename occurs at most once
 func getFile(filename string) (file *token.File) {
-	fset.Iterate(func(f *token.File) bool {
+	fsetErrs.Iterate(func(f *token.File) bool {
 		if f.Name() == filename {
 			if file != nil {
 				panic(filename + " used multiple times")
@@ -125,7 +127,7 @@ func compareErrors(t *testing.T, expected map[token.Pos]string, found scanner.Er
 	if len(expected) > 0 {
 		t.Errorf("%d errors not reported:", len(expected))
 		for pos, msg := range expected {
-			t.Errorf("%s: %s\n", fset.Position(pos), msg)
+			t.Errorf("%s: %s\n", fsetErrs.Position(pos), msg)
 		}
 	}
 }
@@ -137,7 +139,7 @@ func checkErrors(t *testing.T, filename string, input interface{}) {
 		return
 	}
 
-	_, err = ParseFile(fset, filename, src, DeclarationErrors)
+	_, err = ParseFile(fsetErrs, filename, src, DeclarationErrors)
 	found, ok := err.(scanner.ErrorList)
 	if err != nil && !ok {
 		t.Error(err)
@@ -153,6 +155,7 @@ func checkErrors(t *testing.T, filename string, input interface{}) {
 }
 
 func TestErrors(t *testing.T) {
+	fsetErrs = token.NewFileSet()
 	list, err := ioutil.ReadDir(testdata)
 	if err != nil {
 		t.Fatal(err)

src/pkg/go/types/check_test.go

@@ -230,12 +230,17 @@ func checkFiles(t *testing.T, testname string, testfiles []string) {
 	}
 }
 
+var testBuiltinsDeclared = false
+
 func TestCheck(t *testing.T) {
 	// Declare builtins for testing.
 	// Not done in an init func to avoid an init race with
 	// the construction of the Universe var.
+	if !testBuiltinsDeclared {
+		testBuiltinsDeclared = true
 		def(&Func{Name: "assert", Type: &builtin{_Assert, "assert", 1, false, true}})
 		def(&Func{Name: "trace", Type: &builtin{_Trace, "trace", 0, true, true}})
+	}
 
 	// For easy debugging w/o changing the testing code,
 	// if there is a local test file, only test that file.

src/pkg/net/http/responsewrite_test.go

@@ -15,7 +15,8 @@ type respWriteTest struct {
 	Raw  string
 }
 
-var respWriteTests = []respWriteTest{
+func TestResponseWrite(t *testing.T) {
+	respWriteTests := []respWriteTest{
 		// HTTP/1.0, identity coding; no trailer
 		{
 			Response{
@@ -89,9 +90,8 @@ var respWriteTests = []respWriteTest{
 				"Foo: Bar Baz\r\n" +
 				"\r\n",
 		},
-}
+	}
 
-func TestResponseWrite(t *testing.T) {
 	for i := range respWriteTests {
 		tt := &respWriteTests[i]
 		var braw bytes.Buffer

src/pkg/net/http/serve_test.go

@@ -184,10 +184,11 @@ var vtests = []struct {
 }
 
 func TestHostHandlers(t *testing.T) {
+	mux := NewServeMux()
 	for _, h := range handlers {
-		Handle(h.pattern, stringHandler(h.msg))
+		mux.Handle(h.pattern, stringHandler(h.msg))
 	}
-	ts := httptest.NewServer(nil)
+	ts := httptest.NewServer(mux)
 	defer ts.Close()
 
 	conn, err := net.Dial("tcp", ts.Listener.Addr().String())

src/pkg/os/exec/exec_test.go

@@ -144,6 +144,8 @@ func TestPipes(t *testing.T) {
 	check("Wait", err)
 }
 
+var testedAlreadyLeaked = false
+
 func TestExtraFiles(t *testing.T) {
 	if runtime.GOOS == "windows" {
 		t.Skip("no operating system support; skipping")
@@ -151,12 +153,15 @@ func TestExtraFiles(t *testing.T) {
 
 	// Ensure that file descriptors have not already been leaked into
 	// our environment.
+	if !testedAlreadyLeaked {
+		testedAlreadyLeaked = true
 		for fd := os.Stderr.Fd() + 1; fd <= 101; fd++ {
 			err := os.NewFile(fd, "").Close()
 			if err == nil {
 				t.Logf("Something already leaked - closed fd %d", fd)
 			}
 		}
+	}
 
 	// Force network usage, to verify the epoll (or whatever) fd
 	// doesn't leak to the child,