assertEqualHashCode(Predicates.or(p1, p2), Predicates.or(p1, p2));

    // While not a contractual requirement, we'd like the hash codes for ands
    // & ors of the same predicates to not collide.
    assertTrue(Predicates.and(p1, p2).hashCode() != Predicates.or(p1, p2).hashCode());
  }

  @J2ktIncompatible
  @GwtIncompatible // reflection
  public void testNulls() throws Exception {