Improve the Data.IntMap.mergeWithKey test to test more cases and have clearer output

Author: gereeter

tests/intmap-properties.hs

@@ -552,7 +552,7 @@ test_toDescList = toDescList (fromList [(5,"a"), (3,"b")]) @?= [(5,"a"), (3,"b")
 test_showTree :: Assertion
 test_showTree =
        (let t = fromDistinctAscList [(x,()) | x <- [1..5]]
-        in showTree t) @?= "*\n+--*\n|  +-- 1:=()\n|  +--*\n|     +-- 2:=()\n|     +-- 3:=()\n+--*\n   +-- 4:=()\n   +-- 5:=()\n"
+        in showTree t) @?= "1 ()\n+--5 ()\n   |\n   +--3 ()\n   |  |\n   |  +-.\n   |  |\n   |  +--2 ()\n   |     |\n   |     +-.\n   |     |\n   |     +-.\n   |\n   +--4 ()\n      |\n      +-.\n      |\n      +-.\n"
 
 test_fromAscList :: Assertion
 test_fromAscList = do
@@ -815,17 +815,9 @@ prop_withoutKeys m s0 = m `withoutKeys` s === filterWithKey (\k _ -> k `IntSet.n
     s = keysSet s0
     reduced = withoutKeys m s
 
-prop_mergeWithKeyModel :: [(Int,Int)] -> [(Int,Int)] -> Bool
-prop_mergeWithKeyModel xs ys
-  = and [ testMergeWithKey f keep_x keep_y
-        | f <- [ \_k x1  _x2 -> Just x1
-               , \_k _x1 x2  -> Just x2
-               , \_k _x1 _x2 -> Nothing
-               , \k  x1  x2  -> if k `mod` 2 == 0 then Nothing else Just (2 * x1 + 3 * x2)
-               ]
-        , keep_x <- [ True, False ]
-        , keep_y <- [ True, False ]
-        ]
+prop_mergeWithKeyModel :: Fun (Int, Int, Int) (Maybe Int) -> Bool -> Bool -> [(Int,Int)] -> [(Int,Int)] -> Bool
+prop_mergeWithKeyModel f keep_x keep_y xs ys
+  = testMergeWithKey (apply3 f) keep_x keep_y
 
     where xs' = List.nubBy ((==) `on` fst) xs
           ys' = List.nubBy ((==) `on` fst) ys