@Test
  public void defaultCollectorReturnsSingleResult() {
    ResultCollector rc = getExecution().execute((context) -> {
      context.getResultSender().lastResult("done");
    });
    List<String> results = (List<String>) rc.getResult();
    assertEquals(numberOfExecutions(), results.size());
    results.stream().forEach(element -> assertEquals("done", element));
  }
Return the number of members the function is expected to execute on
geode-core/src/distributedTest/java/org/apache/geode/internal/cache/execute/FunctionServiceBase.java