@Test(expected = IllegalArgumentException.class)
public void testSetWrongTileSource() {

    // Only required by the super-constructor:
    IRegisterReceiver registerReceiver = mock(IRegisterReceiver.class);
    NicTileSource goodTileSource = mock(NicTileSource.class);
    ITileSource badTileSource = mock(ITileSource.class);
    AssetTileProvider atp = new AssetTileProvider(registerReceiver, goodTileSource, null);
    atp.setTileSource(badTileSource);
}