@Test
  public void testIsClusterKerberosEnabled_true() throws Exception {
    KerberosHelper kerberosHelper = injector.getInstance(KerberosHelper.class);

    Cluster cluster = createStrictMock(Cluster.class);

    expect(cluster.getSecurityType()).andReturn(SecurityType.KERBEROS);

    replay(cluster);
    assertTrue(kerberosHelper.isClusterKerberosEnabled(cluster));
    verify(cluster);
  }
Tests that when regenerating keytabs for an upgrade, that the retry allowed
boolean is set on the tasks created.

@throws Exception
ambari-server/src/test/java/org/apache/ambari/server/controller/KerberosHelperTest.java