assertFalse(isInteger.apply(2.0f));
    assertFalse(isInteger.apply(""));
    assertFalse(isInteger.apply(null));
  }

  @GwtIncompatible // Predicates.instanceOf
  public void testIsInstanceOf_subclass() {
    Predicate<@Nullable Object> isNumber = Predicates.instanceOf(Number.class);

    assertTrue(isNumber.apply(1));
    assertTrue(isNumber.apply(2.0f));
    assertFalse(isNumber.apply(""));