}

    void hasOutputsWhenNonEmptyOutputFilesRegistered() {
        when:
        outputs.file('a')

        then:
        outputs.hasOutput
    }

    void hasOutputsWhenUpToDatePredicateRegistered() {
        when:
        outputs.upToDateWhen { false }

        then:
        outputs.hasOutput
    }

    void canSpecifyUpToDatePredicateUsingClosure() {