@Override
    public void startLeaderElection(LeaderContender contender) throws Exception {
        Preconditions.checkNotNull(contender);
        parentService.register(componentId, contender);
    }
@Test
    void testContenderRegistrationNull() throws Exception {
        try (final DefaultLeaderElection testInstance =
                new DefaultLeaderElection(
                        TestingAbstractLeaderElectionService.newBuilder().build(),
                        DEFAULT_TEST_COMPONENT_ID)) {
            assertThatThrownBy(() -> testInstance.startLeaderElection(null))
                    .isInstanceOf(NullPointerException.class);
        }
    }