given:
        DaemonInfo d1 = registerDaemon(Idle)
        DaemonInfo d2 = registerDaemon(Idle)

        when:
        compatible = [ d1, d2 ]

        then:
        wouldExpire(d1)
        wouldExpire(d2)
    }

    def "does not expire when there are no compatible daemons"() {
        given:
        DaemonInfo d1 = registerDaemon(Idle)
        DaemonInfo d2 = registerDaemon(Idle)

    def "does not expire when there is only one daemon"() {
        given:
        DaemonInfo d1 = registerDaemon(Idle)

        expect:
        !wouldExpire(d1)
    }

    def "expires given more than 1 daemon"() {
        given:
        DaemonInfo d1 = registerDaemon(Idle)
        DaemonInfo d2 = registerDaemon(Idle)

        expect:
        wouldExpire(d1)
        !wouldExpire(d2)
    }

    DaemonRegistry registry

    def setup() {
        // Start with a new registry on each test.
        registry = new EmbeddedDaemonRegistry()
    }

    DaemonInfo registerDaemon(DaemonStateControl.State state, long lastIdle = -1) {
        final String uid = UUID.randomUUID().toString()
        final int id = registry.getAll().size() + 1