Hello, I'm trying to use quickcheck with test-framework. QuickCheck site says I can use a function called collect to see statistics of data generation. The function "collect" doesn't seem to print anything, though. This is the output I get after running cabal test: Running 1 test suites... Test suite reference: RUNNING... Test suite reference: PASS Test suite logged to: dist/test/100doors-0.1-reference.log 1 of 1 test suites (1 of 1 test cases) passed. This is what I see inside the log: Test suite reference: RUNNING... Main: flipped door is different state: [OK, passed 100 tests] flipDoors creates a different list of doors unless empty: [OK, passed 100 tests] Properties Total Passed 2 2 Failed 0 0 Total 2 2 Test suite reference: PASS Test suite logged to: dist/test/100doors-0.1-reference.log This is my test code (stripping out the boring parts): instance Arbitrary Door where arbitrary = elements [Opened, Closed] prop_flipped_door_is_different_state door = door /= flipDoor door prop_flipDoors_creates_a_different_list_of_doors_unless_empty n doors = collect n $ (not $ null doors) ==> doors /= (flipDoors n doors) []'s Rafael