from, to := "doesnt-exist", "dest"

	Mkdir(to, 0777)

	if err := Rename(from, to); !IsNotExist(err) {
		t.Errorf("Rename(%q, %q) = %v; want an IsNotExist error", from, to, err)
	}
}

func TestRenameToDirFailed(t *testing.T) {
	defer chtmpdir(t)()
	from, to := "renamefrom", "renameto"

	Mkdir(from, 0777)
	Mkdir(to, 0777)

	err := Rename(from, to)
	switch err := err.(type) {

	if !*testWork {
		defer removeAll(testTmpDir)
	}

	testGOCACHE, _ = cache.DefaultDir()
	if testenv.HasGoBuild() {
		testBin = filepath.Join(testTmpDir, "testbin")
		if err := os.Mkdir(testBin, 0777); err != nil {
			log.Fatal(err)
		}
		testGo = filepath.Join(testBin, "go"+exeSuffix)
		gotool, err := testenv.GoTool()
		if err != nil {
			fmt.Fprintln(os.Stderr, "locating go tool: ", err)
			os.Exit(2)

	c.tempDirMu.Unlock()

	if c.tempDirErr != nil {
		c.Fatalf("TempDir: %v", c.tempDirErr)
	}

	dir := fmt.Sprintf("%s%c%03d", c.tempDir, os.PathSeparator, seq)
	if err := os.Mkdir(dir, 0777); err != nil {
		c.Fatalf("TempDir: %v", err)
	}
	return dir
}

// removeAll is like os.RemoveAll, but retries Windows "Access is denied."
// errors up to an arbitrary timeout.
//