MarvelApiConfig { public static MarvelApiConfig with(String publicKey, String privateKey) { if (singleton == null) { singleton = new Builder(publicKey, privateKey).build(); } return singleton; } MarvelApiConfig(String publicKey, String privateKey, Retrofit retrofit, boolean debug); static MarvelApiConfig with(String publicKey, String privateKey); Retrofit getRetrofit();  }
@Test(expected = IllegalArgumentException.class) public void shouldThrowInvalidArgumentExceptionWhenCreateWithoutPublicKey() { MarvelApiConfig.with(null, ANY_PRIVATE_KEY); }
@Test(expected = IllegalArgumentException.class) public void shouldThrowInvalidArgumentExceptionWhenCreateWithoutPrivateKey() { MarvelApiConfig.with(ANY_PUBLIC_KEY, null); }