return nil
	}
	sseKMS := crypto.S3KMS.IsEncrypted(objInfo.UserDefined)
	sseS3 := crypto.S3.IsEncrypted(objInfo.UserDefined)
	if !sseKMS && !sseS3 { // neither sse-s3 nor sse-kms disallowed
		return errInvalidEncryptionParameters
	}
	if sseKMS && r.Encryption.Type == sses3 { // previously encrypted with sse-kms, now sse-s3 disallowed
		return errInvalidEncryptionParameters
	}

	testCases := []struct {
		volumeName     string
		prefix         string
		expectedResult []string
		expectErr      bool
	}{
		{"foo", "path", []string{"to/"}, false},
		// prefix not found error.
		{"foo", "nodir", nil, true},
	}

	for i, testCase := range testCases {
		result, err := storage.ListDir(context.Background(), "", testCase.volumeName, testCase.prefix, -1)
		expectErr := (err != nil)