when:
        renderer.onOutput(event)

        then:
        1 * listener.onOutput(event)
    }

    def "formats given message with an incrementing timer"() {
        def event1 = startRootBuildOperation(1)
        def event2 = event('2')

        when:
        renderer.onOutput(event1)
        renderer.onOutput(updateNow())

        then: