sampleDockerConfig := fmt.Sprintf(`{
   "%s": {
     "email": %q,
     "auth": %q
   }
}`, test.globURL, email, auth)

		keyring := &BasicDockerKeyring{}
		if cfg, err := ReadDockerConfigFileFromBytes([]byte(sampleDockerConfig)); err != nil {
			t.Errorf("Error processing json blob %q, %v", sampleDockerConfig, err)
		} else {
			keyring.Add(cfg)
		}

		return nil, err
	}

	if limitedReader.N <= 0 {
		return nil, errors.New("the read limit is reached")
	}

	return contents, nil
}

// ReadDockerConfigFileFromBytes read a docker config file from the given bytes
func ReadDockerConfigFileFromBytes(contents []byte) (cfg DockerConfig, err error) {
	if err = json.Unmarshal(contents, &cfg); err != nil {
		return nil, errors.New("error occurred while trying to unmarshal json")

			errorExpected:    true,
			expectedErrorMsg: "error occurred while trying to unmarshal json",
		},
	}

	for _, tc := range testCases {
		cfg, err := ReadDockerConfigFileFromBytes(tc.input)
		if err != nil && !tc.errorExpected {
			t.Fatalf("Error was not expected: %v", err)
		}
		if err != nil && tc.errorExpected {
			if !reflect.DeepEqual(err.Error(), tc.expectedErrorMsg) {