### Question:
FlatLogListener implements LogListener, Configurable, Destroyable { @Override public void setConfiguration(Configuration cfg) throws ConfigurationException { mapper.setConfiguration(cfg); }  @Override void setConfiguration(Configuration cfg); @Override synchronized LogEvent log(LogEvent ev); @Override void destroy();  }### Answer:
@Test void testShouldDelegateSetConfigurationToMapper() throws ConfigurationException { FlatLogListener listener = new FlatLogListener(); listener.mapper = mock(RemoveNewLinesMapper.class); SimpleConfiguration cfg = new SimpleConfiguration(); listener.setConfiguration(cfg); verify(listener.mapper).setConfiguration(cfg); }