@Test
    void no_op_synchronous_remote_task_can_complete_immediately_if_current_state_already_acked() throws Exception {
        RemoteTaskFixture fixture = createFixtureWith(optionsWithZeroTransitionTime());
        fixture.markStorageNodeDown(0);
        MockTask task = fixture.scheduleNoOpVersionDependentTask(); // Tries to set node 0 into Down; already in that state

        assertTrue(task.isInvoked());
        assertFalse(task.isCompleted());

        fixture.processScheduledTask(); // Deferred tasks processing; should complete tasks
        assertTrue(task.isCompleted());
    }
Class for testing states of all nodes. Will fail in constructor with
debug message on non-expected results.
clustercontroller-core/src/test/java/com/yahoo/vespa/clustercontroller/core/StateChangeTest.java