os: use testenv.MustHaveSymlink to simplify symlink tests

Cleanup test code for symbolic links.

Change-Id: I7a116e4d5c0e955578eca53c1af559e9092f60cd
Reviewed-on: https://go-review.googlesource.com/27572Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

src/os/os_test.go

@@ -25,8 +25,6 @@ import (
 	"time"
 )
 
-var supportsSymlinks = true
-
 var dot = []string{
 	"dir_unix.go",
 	"env.go",
@@ -652,14 +650,8 @@ func chtmpdir(t *testing.T) func() {
 }
 
 func TestSymlink(t *testing.T) {
-	switch runtime.GOOS {
-	case "android", "nacl", "plan9":
-		t.Skipf("skipping on %s", runtime.GOOS)
-	case "windows":
-		if !supportsSymlinks {
-			t.Skipf("skipping on %s", runtime.GOOS)
-		}
-	}
+	testenv.MustHaveSymlink(t)
+
 	defer chtmpdir(t)()
 	from, to := "symlinktestfrom", "symlinktestto"
 	Remove(from) // Just in case.
@@ -719,14 +711,8 @@ func TestSymlink(t *testing.T) {
 }
 
 func TestLongSymlink(t *testing.T) {
-	switch runtime.GOOS {
-	case "android", "plan9", "nacl":
-		t.Skipf("skipping on %s", runtime.GOOS)
-	case "windows":
-		if !supportsSymlinks {
-			t.Skipf("skipping on %s", runtime.GOOS)
-		}
-	}
+	testenv.MustHaveSymlink(t)
+
 	defer chtmpdir(t)()
 	s := "0123456789abcdef"
 	// Long, but not too long: a common limit is 255.

src/os/os_windows_test.go

@@ -18,22 +18,6 @@ import (
 var supportJunctionLinks = true
 
 func init() {
-	tmpdir, err := ioutil.TempDir("", "symtest")
-	if err != nil {
-		panic("failed to create temp directory: " + err.Error())
-	}
-	defer os.RemoveAll(tmpdir)
-
-	err = os.Symlink("target", filepath.Join(tmpdir, "symlink"))
-	if err != nil {
-		err = err.(*os.LinkError).Err
-		switch err {
-		case syscall.EWINDOWS, syscall.ERROR_PRIVILEGE_NOT_HELD:
-			supportsSymlinks = false
-		}
-	}
-	defer os.Remove("target")
-
 	b, _ := osexec.Command("cmd", "/c", "mklink", "/?").Output()
 	if !strings.Contains(string(b), " /J ") {
 		supportJunctionLinks = false

src/os/path_test.go

@@ -5,6 +5,7 @@
 package os_test
 
 import (
+	"internal/testenv"
 	"io/ioutil"
 	. "os"
 	"path/filepath"
@@ -169,14 +170,7 @@ func TestRemoveAll(t *testing.T) {
 }
 
 func TestMkdirAllWithSymlink(t *testing.T) {
-	switch runtime.GOOS {
-	case "android", "nacl", "plan9":
-		t.Skipf("skipping on %s", runtime.GOOS)
-	case "windows":
-		if !supportsSymlinks {
-			t.Skipf("skipping on %s", runtime.GOOS)
-		}
-	}
+	testenv.MustHaveSymlink(t)
 
 	tmpDir, err := ioutil.TempDir("", "TestMkdirAllWithSymlink-")
 	if err != nil {