os, path/filepath: use T.Cleanup to restore the original working directory

Updates #45182

Change-Id: Iaf3bdcc345c72fa9669fdc99908ada4e89904edd
Reviewed-on: https://go-review.googlesource.com/c/go/+/306290
Trust: Emmanuel Odeke <emmanuel@orijtech.com>
Run-TryBot: Emmanuel Odeke <emmanuel@orijtech.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

3 files changed, 45 insertions, 74 deletions

diff --git a/src/os/os_windows_test.go b/src/os/os_windows_test.go
index b0929b4f30..b4339c3f7e 100644
--- a/src/os/os_windows_test.go
+++ b/src/os/os_windows_test.go
@@ -35,16 +35,7 @@ func TestSameWindowsFile(t *testing.T) {
 		t.Fatal(err)
 	}
 	defer os.RemoveAll(temp)
-
-	wd, err := os.Getwd()
-	if err != nil {
-		t.Fatal(err)
-	}
-	err = os.Chdir(temp)
-	if err != nil {
-		t.Fatal(err)
-	}
-	defer os.Chdir(wd)
+	chdir(t, temp)
 
 	f, err := os.Create("a")
 	if err != nil {
@@ -94,16 +85,7 @@ func testDirLinks(t *testing.T, tests []dirLinkTest) {
 		t.Fatal(err)
 	}
 	defer os.RemoveAll(tmpdir)
-
-	oldwd, err := os.Getwd()
-	if err != nil {
-		t.Fatal(err)
-	}
-	err = os.Chdir(tmpdir)
-	if err != nil {
-		t.Fatal(err)
-	}
-	defer os.Chdir(oldwd)
+	chdir(t, tmpdir)
 
 	dir := filepath.Join(tmpdir, "dir")
 	err = os.Mkdir(dir, 0777)
@@ -444,15 +426,7 @@ func TestNetworkSymbolicLink(t *testing.T) {
 	}
 	defer os.RemoveAll(dir)
 
-	oldwd, err := os.Getwd()
-	if err != nil {
-		t.Fatal(err)
-	}
-	err = os.Chdir(dir)
-	if err != nil {
-		t.Fatal(err)
-	}
-	defer os.Chdir(oldwd)
+	chdir(t, dir)
 
 	shareName := "GoSymbolicLinkTestShare" // hope no conflictions
 	sharePath := filepath.Join(dir, shareName)
@@ -604,16 +578,7 @@ func TestOpenVolumeName(t *testing.T) {
 		t.Fatal(err)
 	}
 	defer os.RemoveAll(tmpdir)
-
-	wd, err := os.Getwd()
-	if err != nil {
-		t.Fatal(err)
-	}
-	err = os.Chdir(tmpdir)
-	if err != nil {
-		t.Fatal(err)
-	}
-	defer os.Chdir(wd)
+	chdir(t, tmpdir)
 
 	want := []string{"file1", "file2", "file3", "gopher.txt"}
 	sort.Strings(want)
@@ -1226,16 +1191,7 @@ func TestWindowsReadlink(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-
-	wd, err := os.Getwd()
-	if err != nil {
-		t.Fatal(err)
-	}
-	err = os.Chdir(tmpdir)
-	if err != nil {
-		t.Fatal(err)
-	}
-	defer os.Chdir(wd)
+	chdir(t, tmpdir)
 
 	vol := filepath.VolumeName(tmpdir)
 	output, err := osexec.Command("cmd", "/c", "mountvol", vol, "/L").CombinedOutput()
diff --git a/src/os/removeall_test.go b/src/os/removeall_test.go
index 3a2f6e3759..45a85792ce 100644
--- a/src/os/removeall_test.go
+++ b/src/os/removeall_test.go
@@ -156,6 +156,25 @@ func TestRemoveAllLarge(t *testing.T) {
 	}
 }
 
+// chdir changes the current working directory to the named directory,
+// and then restore the original working directory at the end of the test.
+func chdir(t *testing.T, dir string) {
+	olddir, err := os.Getwd()
+	if err != nil {
+		t.Fatalf("chdir: %v", err)
+	}
+	if err := os.Chdir(dir); err != nil {
+		t.Fatalf("chdir %s: %v", dir, err)
+	}
+
+	t.Cleanup(func() {
+		if err := os.Chdir(olddir); err != nil {
+			t.Errorf("chdir to original working directory %s: %v", olddir, err)
+			os.Exit(1)
+		}
+	})
+}
+
 func TestRemoveAllLongPath(t *testing.T) {
 	switch runtime.GOOS {
 	case "aix", "darwin", "ios", "dragonfly", "freebsd", "linux", "netbsd", "openbsd", "illumos", "solaris":
@@ -164,21 +183,12 @@ func TestRemoveAllLongPath(t *testing.T) {
 		t.Skip("skipping for not implemented platforms")
 	}
 
-	prevDir, err := Getwd()
-	if err != nil {
-		t.Fatalf("Could not get wd: %s", err)
-	}
-
 	startPath, err := os.MkdirTemp("", "TestRemoveAllLongPath-")
 	if err != nil {
 		t.Fatalf("Could not create TempDir: %s", err)
 	}
 	defer RemoveAll(startPath)
-
-	err = Chdir(startPath)
-	if err != nil {
-		t.Fatalf("Could not chdir %s: %s", startPath, err)
-	}
+	chdir(t, startPath)
 
 	// Removing paths with over 4096 chars commonly fails
 	for i := 0; i < 41; i++ {
@@ -195,11 +205,6 @@ func TestRemoveAllLongPath(t *testing.T) {
 		}
 	}
 
-	err = Chdir(prevDir)
-	if err != nil {
-		t.Fatalf("Could not chdir %s: %s", prevDir, err)
-	}
-
 	err = RemoveAll(startPath)
 	if err != nil {
 		t.Errorf("RemoveAll could not remove long file path %s: %s", startPath, err)
diff --git a/src/path/filepath/path_test.go b/src/path/filepath/path_test.go
index 1d9889d320..51eca49e4c 100644
--- a/src/path/filepath/path_test.go
+++ b/src/path/filepath/path_test.go
@@ -410,6 +410,25 @@ func mark(d fs.DirEntry, err error, errors *[]error, clear bool) error {
 	return nil
 }
 
+// chdir changes the current working directory to the named directory,
+// and then restore the original working directory at the end of the test.
+func chdir(t *testing.T, dir string) {
+	olddir, err := os.Getwd()
+	if err != nil {
+		t.Fatalf("getwd %s: %v", dir, err)
+	}
+	if err := os.Chdir(dir); err != nil {
+		t.Fatalf("chdir %s: %v", dir, err)
+	}
+
+	t.Cleanup(func() {
+		if err := os.Chdir(olddir); err != nil {
+			t.Errorf("restore original working directory %s: %v", olddir, err)
+			os.Exit(1)
+		}
+	})
+}
+
 func chtmpdir(t *testing.T) (restore func()) {
 	oldwd, err := os.Getwd()
 	if err != nil {
@@ -1496,16 +1515,7 @@ func TestEvalSymlinksAboveRootChdir(t *testing.T) {
 		t.Fatal(err)
 	}
 	defer os.RemoveAll(tmpDir)
-
-	wd, err := os.Getwd()
-	if err != nil {
-		t.Fatal(err)
-	}
-	defer os.Chdir(wd)
-
-	if err := os.Chdir(tmpDir); err != nil {
-		t.Fatal(err)
-	}
+	chdir(t, tmpDir)
 
 	subdir := filepath.Join("a", "b")
 	if err := os.MkdirAll(subdir, 0777); err != nil {