TransformerMap implements NumberTransformer, Serializable { public boolean containsTransformer(NumberTransformer value) { return map.containsValue(value); } TransformerMap(); boolean containsClass(Class<?> key); boolean containsTransformer(NumberTransformer value); NumberTransformer getTransformer(Class<?> key); NumberTransformer putTransformer(Class<?> key, NumberTransformer transformer); NumberTransformer removeTransformer(Class<?> key); void clear(); Set<Class<?>> classes(); Collection<NumberTransformer> transformers(); double transform(Object o); @Override boolean equals(Object other); @Override int hashCode();  }
@Test public void testContainsTransformer(){ NumberTransformer expected = new DefaultTransformer(); TransformerMap map = new TransformerMap(); map.putTransformer(TransformerMapTest.class, expected); Assert.assertTrue(map.containsTransformer(expected)); }