@Test
public void testTransformSimple() {

  Map<String, Object> context = new HashMap<String, Object>();
  context.put("key", "value");
  context.put("key1", "value1");
  context.put("key2", "value2");
  ContextTransformer transformer = new ContextTransformer("key");
  Assert.assertEquals("value", transformer.transform(context));
}