assertNotInstantiable(new TypeToken<ImmutableMultiset<EmptyEnum>>() {});
  }

  public void testImmutableCollection() {
    assertFreshInstance(new TypeToken<ImmutableCollection<String>>() {});
    assertNotInstantiable(new TypeToken<ImmutableCollection<EmptyEnum>>() {});
  }

  public void testImmutableMap() {

    assertThat(ArbitraryInstances.get(Object[].class)).isEmpty();
    assertThat(ArbitraryInstances.get(String[].class)).isEmpty();
  }

  public void testGet_enum() {
    assertNull(ArbitraryInstances.get(EmptyEnum.class));
    assertEquals(Direction.UP, ArbitraryInstances.get(Direction.class));
  }

  public void testGet_interface() {
    assertNull(ArbitraryInstances.get(SomeInterface.class));
  }

    assertThat(ArbitraryInstances.get(Object[].class)).isEmpty();
    assertThat(ArbitraryInstances.get(String[].class)).isEmpty();
  }

  public void testGet_enum() {
    assertNull(ArbitraryInstances.get(EmptyEnum.class));
    assertEquals(Direction.UP, ArbitraryInstances.get(Direction.class));
  }

  public void testGet_interface() {
    assertNull(ArbitraryInstances.get(SomeInterface.class));
  }

    new IntArrayDefaultValueChecker().check();
  }

  private enum EmptyEnum {}

  private static class EmptyEnumDefaultValueChecker extends DefaultValueChecker {

    @SuppressWarnings("unused") // called by NullPointerTester
    @Keep
    public void checkArray(EmptyEnum object, String s) {
      calledWith(object, s);
    }

    void check() {
      try {