ServiceReference reference = mock(ServiceReference.class);
when(reference.getPropertyKeys()).thenReturn(new String[] {"service.id", "foo"});
when(reference.getProperty("service.id")).thenReturn(42);
when(reference.getProperty("foo")).thenReturn("test");
ServiceReference newReference = new TransformedServiceReferenceImpl(reference).addProperty("location",
"kitchen");
assertThat(newReference.getPropertyKeys()).contains("location");
assertThat(newReference.getProperty("location")).isEqualTo("kitchen");
}