// Apply withDefaultPort(), yielding hp2.
    final boolean badDefaultPort = (defaultPort < 0 || defaultPort > 65535);
    HostAndPort hp2 = null;
    try {
      hp2 = hp.withDefaultPort(defaultPort);
      assertFalse(badDefaultPort);
    } catch (IllegalArgumentException e) {
      assertTrue(badDefaultPort);
    }

    // Check the pre-withDefaultPort() instance.
    if (expectHasExplicitPort) {