public boolean fence(HAServiceTarget fromSvc) {
    return fence(fromSvc, null);
  }
@Test
  public void testArglessFencer() throws BadFencingConfigurationException {
    NodeFencer fencer = setupFencer(
        AlwaysSucceedFencer.class.getName());
    assertTrue(fencer.fence(MOCK_TARGET));
    // One call to each, since top fencer fails
    assertEquals(1, AlwaysSucceedFencer.fenceCalled);
    assertSame(MOCK_TARGET, AlwaysSucceedFencer.fencedSvc);
    assertEquals(null, AlwaysSucceedFencer.callArgs.get(0));
  }