@Test
void shouldReturnMinusOneWhenThereIsNoMediaToDisplay() {

    MediaFileReader mfr = new MediaFileReader(mockGameContext) {
        @Override
        public File getMediaPlayerDirectory() {
            return testDir;
        }
    };
    assertEquals(mfr.getMediaList().size(), 0);
    assertEquals(mfr.getIndexOfFirstToDisplay(), -1);
}