@Test
public void buildRequestTest() throws IOException {

    doReturn(mockedRequest).when(mockedDriveService).generateRequest(anyString(), anyString());
    assertNull(driveHelper.buildRequest(null, null));
    assertNull(driveHelper.buildRequest("some query", null));
    assertNull(driveHelper.buildRequest(null, "some fields"));
    assertNotNull(driveHelper.buildRequest("some query", "some fields"));
}