Set 3a Ex 7&8: better error messages for infinite loops

Author: opqdonut

exercises/Set3aTest.hs

@@ -114,19 +114,19 @@ ex6_powers_large = m_powers 27 -- 5^27 still fits in Int
 
 ex7_while_number = property $ do
   n <- choose (0,20 :: Integer)
-  return $ counterexample ("while (/="++show n++") (+1) 0") $
+  return $ counterexample ("while (/="++show n++") (+1) 0") $ within timeLimit $
     while (/=n) (+1) 0 ?== n
 
 ex7_while_string = property $ do
   n <- word
   let w = n++n
       p = (/=n)
-  return $ counterexample ("while (/="++show n++") tail "++show w) $
+  return $ counterexample ("while (/="++show n++") tail "++show w) $ within timeLimit $
     while p tail w == n
 
 ex8_whileRight_Left = forAllBlind word $ \w ->
   forAllBlind (choose (1::Int,10)) $ \i ->
-  counterexample ("let f _ = Left " ++ show w ++ " in whileRight f " ++ show i) $
+  counterexample ("let f _ = Left " ++ show w ++ " in whileRight f " ++ show i) $ within timeLimit $
   let f _ = Left w in whileRight f i ?== w
 
 ex8_whileRight_step = property $ do
@@ -137,7 +137,7 @@ ex8_whileRight_step = property $ do
   let log = ceiling . logBase 2 . fromIntegral
       divUp x y = ceiling (fromIntegral x / fromIntegral y)
       answer = start * 2 ^ (log (limit `divUp` start))
-  return $ counterexample ("whileRight (step " ++ show limit ++ ") " ++ show start) $
+  return $ counterexample ("whileRight (step " ++ show limit ++ ") " ++ show start) $ within timeLimit $
     whileRight (step limit) start ?== answer
 
 ex9_1 = property $ do