diff options
| -rw-r--r-- | tests/Properties.hs | 19 |
1 files changed, 18 insertions, 1 deletions
diff --git a/tests/Properties.hs b/tests/Properties.hs index ba82fdc..4924e01 100644 --- a/tests/Properties.hs +++ b/tests/Properties.hs @@ -59,6 +59,22 @@ instance (Integral i, Integral j, Ord a, Arbitrary a) => Arbitrary (StackSet i j return $ fromList (fromIntegral n,sc,ls) coarbitrary = error "no coarbitrary for StackSet" +-- Invariants: +-- +-- * no element should ever appear more than once in a StackSet +-- * the current index should always be valid +-- +-- All operations must preserve this. +-- +invariant (w :: T) = inBounds w && noDuplicates (concat $ M.elems (stacks w)) + where + noDuplicates ws = nub ws == ws + inBounds x = current x >= 0 && current x < sz where sz = M.size (stacks x) + +-- test generator +prop_invariant = invariant + + -- empty StackSets have no windows in them prop_empty n m = n > 0 && m > 0 ==> all null (M.elems (stacks x)) where x = empty n m :: T @@ -295,7 +311,8 @@ main = do n = 100 tests = - [("empty is empty" , mytest prop_empty) + [("StackSet invariants", mytest prop_invariant) + ,("empty is empty" , mytest prop_empty) ,("empty / current" , mytest prop_empty_current) ,("member/push ", mytest prop_member1) |