@Test
  public void twoGatewayReceiversCannotCoexist() {
    Integer locator1Port = locatorSite1.getPort();
    server1 = clusterStartupRule.startServerVM(1, locator1Port);
    String command = CREATE_GATEWAYRECEIVER;
    gfsh.executeAndAssertThat(command).statusIsSuccess()
        .tableHasColumnWithExactValuesInAnyOrder("Member", SERVER_1)
        .tableHasColumnWithValuesContaining("Message",
            "GatewayReceiver created on member \"" + SERVER_1 + "\"");
    gfsh.executeAndAssertThat(command).statusIsError()
        .tableHasColumnWithExactValuesInAnyOrder("Member", SERVER_1)
        .tableHasColumnWithValuesContaining("Status", "ERROR")
        .tableHasColumnWithValuesContaining("Message",
            "java.lang.IllegalStateException: " + A_GATEWAY_RECEIVER_ALREADY_EXISTS_ON_THIS_MEMBER);
  }
DUnit tests for 'create gateway-receiver' command.
geode-wan/src/distributedTest/java/org/apache/geode/internal/cache/wan/wancommand/CreateGatewayReceiverCommandDUnitTest.java