}
        def action = Mock(Action)

        final Task a = task("a")
        final Task b = task("b")

        when:
        taskGraph.beforeTask(closure)
        taskGraph.beforeTask(action)
        taskExecutionListeners.source.beforeExecute(a)
        taskExecutionListeners.source.beforeExecute(b)

        then:
        1 * closure.call(a)
        1 * closure.call(b)