### Question:
GreyscaleImageTransformerImpl implements ImageTransformer { @Override public final Layer transform(final Layer layer, final ValueMap properties) { log.debug("Transforming with [ {} ]", TYPE); layer.grayscale(); return layer; }  @Override final Layer transform(final Layer layer, final ValueMap properties);  }### Answer:
@Test public void testTransform() throws Exception { ValueMap properties = new ValueMapDecorator(map); transformer.transform(layer, properties); verify(layer, times(1)).grayscale(); verifyNoMoreInteractions(layer); }
@Test public void testTransform_emptyParams() throws Exception { ValueMap properties = new ValueMapDecorator(map); transformer.transform(layer, properties); verify(layer, times(1)).grayscale(); }
@Test public void testTransform_nullParams() throws Exception { transformer.transform(layer, null); verify(layer, times(1)).grayscale(); }