@Override
      public void run() {
        getSystem();
        ResultCollector<?, ?> rc =
            FunctionService.onMember(member1Id).execute(new TestOnMembersWithoutCacheFN1());

        try {
          rc.getResult(30, TimeUnit.SECONDS);
          fail("Should have seen an exception");
        } catch (Exception e) {
          if (!(e.getCause() instanceof FunctionInvocationTargetException)) {
            Assert.fail("failed", e);
          }
        }

      }
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