factorial_demo_test.puml

@startuml

!include factorial_demo.puml

!$test_data = {
    "tests" : [
        {"input": "0", "output": "1"},
        {"input": "1", "output": "1"},
        {"input": "2", "output": "2"},
        {"input": "3", "output": "6"},
        {"input": "4", "output": "24"},
        {"input": "5", "output": "120"},
        {"input": "6", "output": "720"},
        {"input": "7", "output": "5040"},
        {"input": "8", "output": "40320"},
        {"input": "9", "output": "362880"},
        {"input": "10", "output": "3628800"},
        {"input": "11", "output": "39916800"},
        {"input": "12", "output": "479001600"},
        /' below input will raise an assert, but there's currently no way to 
        "expect" an assert, preprocessor is not a unit testing framework. ;-) '/
        {"input": "-1", "output": "0"}
    ]
}

!foreach $item in $test_data.tests
    !$expected = %intval($item.output)
    !$actual = $factorial(%intval($item.input))
    !assert $expected == $actual : "expected [" + $expected + "] actual [" + $actual + "]"
!endfor

@enduml