void loseLeadership() throws Exception {
            // Receive leadership loss event; other nodes not voting for us anymore.
            Map<Integer, Integer> leaderVotes = new HashMap<>();
            leaderVotes.put(0, 0);
            leaderVotes.put(1, 1);
            leaderVotes.put(2, 1);
            ctrl.handleFleetData(leaderVotes);
            ctrl.tick();
        }
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