when:
        listener.onOutput("text")

        then:
        1 * appendable.append("text")
        0 * _._
    }

    def canAppendToAWriter() {
        Writer writer = Mock()
        def listener = new StreamBackedStandardOutputListener(writer)

        when:
        listener.onOutput("text")

        then:
        1 * writer.append("text")