assertEquals(CharSource.empty(), ArbitraryInstances.get(CharSource.class));
    assertNotNull(ArbitraryInstances.get(ByteSink.class));
    assertNotNull(ArbitraryInstances.get(CharSink.class));
  }

  public void testGet_reflect() {
    assertNotNull(ArbitraryInstances.get(Type.class));
    assertNotNull(ArbitraryInstances.get(AnnotatedElement.class));
    assertNotNull(ArbitraryInstances.get(GenericDeclaration.class));
  }