@Test
public void getFileNameShouldReturnNullWhenNoFileNameIsFoundInParamMetas(){

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