def task = Stub(Task)
        def owner = Stub(ModelObject)
        owner.taskThatOwnsThisObject >> task
        def action = Mock(Action)

        when:
        var.attachProducer(owner)
        def producer = var.producer

        then:
        producer.known

        when:
        producer.visitProducerTasks(action)

        then:
        1 * action.execute(task)

        return taskMutator.mutate("TaskOutputs.file(Object)", (Callable<TaskOutputFilePropertyBuilder>) () -> {
            StaticValue value = new StaticValue(path);
            value.attachProducer(task);
            TaskOutputFilePropertyRegistration registration = new DefaultTaskOutputFilePropertyRegistration(value, OutputFilePropertyType.FILE);
            registeredFileProperties.add(registration);

        if (displayName == null) {
            return DEFAULT_VALIDATION_DISPLAY_NAME;
        }
        return displayName;
    }

    @Override
    public void attachProducer(ModelObject owner) {
        if (this.producer == null) {
            this.producer = owner;
        } else if (this.producer != owner) {
            TreeFormatter formatter = new TreeFormatter();