@Test
public void testRegisterDecoderWhenDecoderExist() {

    // Setup
    final String subject = "subject";
    final BaseDecoder baseDecoder = mock(BaseDecoder.class);
    when(mockDecoderRegistry.containsKey(subject)).thenReturn(true);
    // Run the test
    languageTranslatorImplUnderTest.registerDecoder(subject, baseDecoder);
    // Verify the results
    verify(mockDecoderRegistry, never()).put(anyString(), any(BaseDecoder.class));
}