Update collatz conjecture tests (#277)

exercism · Sep 7, 2023 · a0c5f57 · a0c5f57
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Showing 3 changed files with 37 additions and 13 deletions.
diff --git a/exercises/practice/collatz-conjecture/.meta/example.rkt b/exercises/practice/collatz-conjecture/.meta/example.rkt
@@ -13,7 +13,7 @@
 (define (collatz n)
   (if (nand (exact-integer? n)
             (positive? n))
-      (error "number must be a positive integer")
+      (error "Only positive integers are allowed")
       (collatz-length n)))
 
 

diff --git a/exercises/practice/collatz-conjecture/.meta/tests.toml b/exercises/practice/collatz-conjecture/.meta/tests.toml
@@ -23,6 +23,16 @@ description = "large number of even and odd steps"
 
 [7d4750e6-def9-4b86-aec7-9f7eb44f95a3]
 description = "zero is an error"
+include = false
+
+[2187673d-77d6-4543-975e-66df6c50e2da]
+description = "zero is an error"
+reimplements = "7d4750e6-def9-4b86-aec7-9f7eb44f95a3"
 
 [c6c795bf-a288-45e9-86a1-841359ad426d]
 description = "negative value is an error"
+include = false
+
+[ec11f479-56bc-47fd-a434-bcd7a31a7a2e]
+description = "negative value is an error"
+reimplements = "c6c795bf-a288-45e9-86a1-841359ad426d"
diff --git a/exercises/practice/collatz-conjecture/collatz-conjecture-test.rkt b/exercises/practice/collatz-conjecture/collatz-conjecture-test.rkt
@@ -5,30 +5,44 @@
 (module+ test
   (require rackunit rackunit/text-ui)
 
+  (define (exn-msg-matches? msg f)
+    (with-handlers ([exn:fail? (lambda (exn)
+                                 (string=? (exn-message exn) msg))])
+      (f)))
+
   (define suite
     (test-suite
-     "collatz-conjecture tests"
+     "collatz conjecture tests"
 
      (test-eqv? "zero steps for one"
                 (collatz 1)
                 0)
+
      (test-eqv? "divide if even"
                 (collatz 16)
                 4)
+
      (test-eqv? "even and odd steps"
                 (collatz 12)
                 9)
+
      (test-eqv? "Large number of even and odd steps"
                 (collatz 1000000)
                 152)
-     (test-exn "zero is an error"
-               exn:fail?
-               (lambda () (collatz 0)))
-     (test-exn "negative value is an error"
-               exn:fail?
-               (lambda () (collatz -15)))
-     (test-exn "non exact value is an error"
-               exn:fail?
-               (lambda () (collatz 3.4)))))
-
-  (run-tests suite))
+
+     (test-true "zero is an error"
+                (exn-msg-matches?
+                  "Only positive integers are allowed"
+                  (lambda () (collatz 0))))
+
+     (test-true "negative value is an error"
+                (exn-msg-matches?
+                  "Only positive integers are allowed"
+                  (lambda () (collatz -15))))
+
+     (test-true "non exact value is an error"
+                (exn-msg-matches?
+                  "Only positive integers are allowed"
+                  (lambda () (collatz 3.4))))))
+
+(run-tests suite))