public static void executeOnMembers_Timedout_byInstance(Integer noOfMembers) {
    assertNotNull(ds);
    Function function = new TestFunction(true, TestFunction.TEST_FUNCTION_RUNNING_FOR_LONG_TIME);
    Execution executor = getExecutionObject(noOfMembers);
    try {
      long timeoutMs = 1000;
      ResultCollector rc = executor.execute(function, timeoutMs, TimeUnit.MILLISECONDS);
      fail("Expected FunctionException: Function did not timeout");
    } catch (Exception ex) {
      if (!(ex.getCause() instanceof FunctionException)) {
        Assert.fail("Function should have timed out", ex);
      }
    }
  }
This tests make sure that, in case of LonerDistributedSystem we dont get ClassCast Exception.
Just making sure that the function executed on lonerDistribuedSystem
geode-core/src/distributedTest/java/org/apache/geode/internal/cache/execute/MemberFunctionExecutionDUnitTest.java