@Test
  public void testAddComponentDuringUpgradeFailsWithNoCandidates() throws Exception {
    PowerMock.replay(m_action);
    replayAll();

    m_candidateHosts.clear();

    m_action.execute(null);

    verifyAll();
  }
Tests that we fail without any candidates.

@throws Exception
ambari-server/src/test/java/org/apache/ambari/server/serveraction/upgrades/AddComponentActionTest.java