@Test
public void getFileNameShouldGetFileNameFromParam(){

    Map<String,Object> metaDatas = Collections.singletonMap("multipart.filename", (Object)"expected");
    Param param = mock(Param.class);
    ParamConfig paramConfig = mock(ParamConfig.class);
    when(paramConfig .getMetaDatas()).thenReturn(metaDatas);
    when(param.getParamConfig()).thenReturn(paramConfig);
    assertEquals("expected", MultiParts.getFileName(param));
}