Added test cases for `Mkdir` & `MkdirAll` to cover empty folder names

gcs_mocks.go

@@ -146,6 +146,10 @@ type writerMock struct {
 }
 
 func (w *writerMock) Write(p []byte) (n int, err error) {
+	if w.name == "" {
+		return 0, gcsfs.ErrEmptyObjectName
+	}
+
 	if w.file == nil {
 		w.file, err = w.fs.Create(w.name)
 		if err != nil {
@@ -157,6 +161,9 @@ func (w *writerMock) Write(p []byte) (n int, err error) {
 }
 
 func (w *writerMock) Close() error {
+	if w.name == "" {
+		return gcsfs.ErrEmptyObjectName
+	}
 	if w.file == nil {
 		var err error
 		if strings.HasSuffix(w.name, "/") {

gcs_test.go

@@ -712,6 +712,15 @@ func TestGcsGlob(t *testing.T) {
 }
 
 func TestGcsMkdir(t *testing.T) {
+	t.Run("empty", func(t *testing.T) {
+		emptyDirName := bucketName
+
+		err := gcsAfs.Mkdir(emptyDirName, 0755)
+		if err == nil {
+			t.Fatal("did not fail upon creation of an empty folder")
+		}
+	})
+	t.Run("success", func(t *testing.T) {
 		dirName := filepath.Join(bucketName, "a-test-dir")
 		var err error
 
@@ -739,9 +748,19 @@ func TestGcsMkdir(t *testing.T) {
 		if err != nil {
 			t.Fatalf("could not delete the folder %s after the test with error: %s", dirName, err)
 		}
+	})
 }
 
 func TestGcsMkdirAll(t *testing.T) {
+	t.Run("empty", func(t *testing.T) {
+		emptyDirName := bucketName
+
+		err := gcsAfs.MkdirAll(emptyDirName, 0755)
+		if err == nil {
+			t.Fatal("did not fail upon creation of an empty folder")
+		}
+	})
+	t.Run("success", func(t *testing.T) {
 		dirName := filepath.Join(bucketName, "a/b/c")
 
 		err := gcsAfs.MkdirAll(dirName, 0755)
@@ -784,4 +803,5 @@ func TestGcsMkdirAll(t *testing.T) {
 		if err != nil {
 			t.Fatalf("failed to remove the folder %s with error: %s", filepath.Join(bucketName, "a"), err)
 		}
+	})
 }