CODEWITHSUNDEEP
f#fscheck
b1g3ar5
b1g3ar5

Reputation: 335

FSCheck generating lists of a specific size

Probably a stupid question, but how do I generate a list of a specific size for FSCheck?

I can restrict using:

let fn_of_2_check xs = (xs.Length=2) ==> fn_of_2 xs

but, obviously, this will throw away loads of lists.

Here fn_of_2 does some test on lists of length 2 only and returns true or false.

Upvotes: 2

Views: 961

Answers (2)

Tomas Petricek
Tomas Petricek

Reputation: 243051

A trivial solution would be to write a test that takes two inputs and builds a two-element list from them:

let fn_of_2_check x y = fn_of_2 [x; y]

However, if you're testing the function for two-elements list only, then perhaps the function should take a two-element tuple as the input. Or, you could write a test that verifies some behaviour for two-element lists and some other behaviour for lists of other length.

(But if you want to check the behaviour for two-element lists specifically, then the above should work.)

Upvotes: 2

Mauricio Scheffer
Mauricio Scheffer

Reputation: 99730

How about:

let listOfLength n = Gen.listOfLength n Arb.generate |> Arb.fromGen
Check.Quick (Prop.forAll (listOfLength 2) fn_of_2)

Upvotes: 6

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