private String getLocatorString(
      final int... locatorPorts) {
    final String hostName = localHost.getHostName();
    return Arrays.stream(locatorPorts)
        .mapToObj(port -> hostName + '[' + port + ']')
        .collect(Collectors.joining(","));
  }
Tests of using the membership APIs to make multiple Membership systems that communicate
with each other and form a group
geode-membership/src/integrationTest/java/org/apache/geode/distributed/internal/membership/gms/MembershipIntegrationTest.java