.addEqualityGroup(Predicates.<@Nullable Integer>equalTo(null))
        .testEquals();
  }

  @J2ktIncompatible
  @GwtIncompatible // SerializableTester
  public void testIsEqualTo_serialization() {
    checkSerialization(Predicates.equalTo(1));
  }

  public void testIsEqualToNull_apply() {
    Predicate<@Nullable Integer> isNull = Predicates.equalTo(null);
    assertTrue(isNull.apply(null));