@Test
public void getContentTypeShouldReturnNullWhenNoContentTypeIsFoundInParamConfigMetas(){

    Map<String,Object> metaDatas = new HashMap<String, Object>();
    ParamConfig paramConfig = mock(ParamConfig.class);
    when(paramConfig.getMetaDatas()).thenReturn(metaDatas);
    assertNull(MultiParts.getContentType(paramConfig));
}