assertThrows(NullPointerException.class, () -> isInteger.apply(null));
  }

  @J2ktIncompatible
  @GwtIncompatible // Predicates.subtypeOf
  public void testSubtypeOf_subclass() {
    Predicate<Class<?>> isNumber = Predicates.subtypeOf(Number.class);

    assertTrue(isNumber.apply(Integer.class));
    assertTrue(isNumber.apply(Float.class));
  }

  @J2ktIncompatible