[Haskell-cafe] Generating test data in QuickCheck
fremenzone at poczta.onet.pl
Mon Oct 15 11:30:34 CEST 2012
I'm writing tests using QuickCheck to test data types that are not an instance of QC's Arbitrary.
To prevent orphan instances I use forAll function instead of instantiating these types as
Arbitrary. The problems arise when I need to generate several different variables for one test.
To do this I either nest calls to forAll or create a pair generator like this:
genPair = liftM2 (,) (myGenerator1) (myGenerator2)
Running time of such tests is very long (both with nesting forAll and using pair generator) and it
gets shorter when I resize myGenerator1 and myGenerator2. This leads me to conslusion that, due
to nesting of generators QC is generating 100*100*100 test cases instead of 100. How do
I "flatten" my generators to always get 100 test cases (or whatever the default number of test
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