@Test
  public void destroyFunction_onlySupportsMember_returnsNull() {
    buffer = "destroy function --id=function1 --members=m1,m2";
    assertThat(parser.parse(buffer)).isNull();
  }
This characterizes the current behavior but it may be incorrect.
geode-gfsh/src/integrationTest/java/org/apache/geode/management/internal/cli/OptionAliasesParsingTest.java