test numbers: mod, rem, quot

1 files changed, 162 insertions, 3 deletions

diff --git a/src/clojure/contrib/test_clojure/numbers.clj b/src/clojure/contrib/test_clojure/numbers.clj
index 4b7c19f3..31341789 100644
--- a/src/clojure/contrib/test_clojure/numbers.clj
+++ b/src/clojure/contrib/test_clojure/numbers.clj
@@ -6,14 +6,16 @@
 ;;  terms of this license.  You must not remove this notice, or any other,
 ;;  from this software.
 ;;
-;;  clojure.contrib.test-clojure.numbers
-;;
 ;;  scgilardi (gmail)
 ;;  Created 30 October 2008
+;;
 
 (ns clojure.contrib.test-clojure.numbers
   (:use clojure.contrib.test-is))
 
+
+;; *** Types ***
+
 (deftest Coerced-Byte
   (let [v (byte 3)]
     (are _
@@ -77,7 +79,164 @@
      (not (float? v)))))
 
 
-;; *** Number predicates ***
+;; *** Functions ***
+
+;; mod
+;; http://en.wikipedia.org/wiki/Modulo_operation
+;; http://mathforum.org/library/drmath/view/52343.html
+;;
+;; is mod correct?
+;; http://groups.google.com/group/clojure/browse_frm/thread/2a0ee4d248f3d131#
+;;
+;; Issue 23: mod (modulo) operator
+;; http://code.google.com/p/clojure/issues/detail?id=23
+
+(deftest test-mod
+  ; wrong number of args
+  (is (thrown? IllegalArgumentException (mod)))
+  (is (thrown? IllegalArgumentException (mod 1)))
+  (is (thrown? IllegalArgumentException (mod 3 2 1)))
+
+  ; divide by zero
+  (is (thrown? ArithmeticException (mod 9 0)))
+  (is (thrown? ArithmeticException (mod 0 0)))
+
+  (are (= _1 _2)
+    (mod 4 2) 0
+    (mod 3 2) 1
+    (mod 6 4) 2
+    (mod 0 5) 0
+
+    (mod 2 1/2) 0
+    (mod 2/3 1/2) 1/6
+    (mod 1 2/3) 1/3
+
+    (mod 4.0 2.0) 0.0
+    (mod 4.5 2.0) 0.5
+
+    ; |num| > |div|, num != k * div
+    (mod 42 5) 2      ; (42 / 5) * 5 + (42 mod 5)        = 8 * 5 + 2        = 42
+    (mod 42 -5) -3    ; (42 / -5) * (-5) + (42 mod -5)   = -9 * (-5) + (-3) = 42
+    (mod -42 5) 3     ; (-42 / 5) * 5 + (-42 mod 5)      = -9 * 5 + 3       = -42
+    (mod -42 -5) -2   ; (-42 / -5) * (-5) + (-42 mod -5) = 8 * (-5) + (-2)  = -42
+
+    ; |num| > |div|, num = k * div
+    (mod 9 3) 0       ; (9 / 3) * 3 + (9 mod 3) = 3 * 3 + 0 = 9
+    (mod 9 -3) 0
+    (mod -9 3) 0
+    (mod -9 -3) 0
+
+    ; |num| < |div|
+    (mod 2 5) 2       ; (2 / 5) * 5 + (2 mod 5)        = 0 * 5 + 2          = 2
+    (mod 2 -5) -3     ; (2 / -5) * (-5) + (2 mod -5)   = (-1) * (-5) + (-3) = 2
+    (mod -2 5) 3      ; (-2 / 5) * 5 + (-2 mod 5)      = (-1) * 5 + 3       = -2
+    (mod -2 -5) -2    ; (-2 / -5) * (-5) + (-2 mod -5) = 0 * (-5) + (-2)    = -2
+
+    ; num = 0, div != 0
+    (mod 0 3) 0       ; (0 / 3) * 3 + (0 mod 3) = 0 * 3 + 0 = 0
+    (mod 0 -3) 0
+  )
+)
+
+;; rem & quot
+;; http://en.wikipedia.org/wiki/Remainder
+
+(deftest test-rem
+  ; wrong number of args
+  (is (thrown? IllegalArgumentException (rem)))
+  (is (thrown? IllegalArgumentException (rem 1)))
+  (is (thrown? IllegalArgumentException (rem 3 2 1)))
+
+  ; divide by zero
+  (is (thrown? ArithmeticException (rem 9 0)))
+  (is (thrown? ArithmeticException (rem 0 0)))
+  
+  (are (= _1 _2)
+    (rem 4 2) 0
+    (rem 3 2) 1
+    (rem 6 4) 2
+    (rem 0 5) 0
+
+    (rem 2 1/2) 0
+    (rem 2/3 1/2) 1/6
+    (rem 1 2/3) 1/3
+
+    (rem 4.0 2.0) 0.0
+    (rem 4.5 2.0) 0.5
+
+    ; |num| > |div|, num != k * div
+    (rem 42 5) 2      ; (8 * 5) + 2 == 42
+    (rem 42 -5) 2     ; (-8 * -5) + 2 == 42
+    (rem -42 5) -2    ; (-8 * 5) + -2 == -42
+    (rem -42 -5) -2   ; (8 * -5) + -2 == -42
+
+    ; |num| > |div|, num = k * div
+    (rem 9 3) 0
+    (rem 9 -3) 0
+    (rem -9 3) 0
+    (rem -9 -3) 0
+
+    ; |num| < |div|
+    (rem 2 5) 2
+    (rem 2 -5) 2
+    (rem -2 5) -2
+    (rem -2 -5) -2
+    
+    ; num = 0, div != 0
+    (rem 0 3) 0
+    (rem 0 -3) 0
+  )
+)
+
+(deftest test-quot
+  ; wrong number of args
+  (is (thrown? IllegalArgumentException (quot)))
+  (is (thrown? IllegalArgumentException (quot 1)))
+  (is (thrown? IllegalArgumentException (quot 3 2 1)))
+
+  ; divide by zero
+  (is (thrown? ArithmeticException (quot 9 0)))
+  (is (thrown? ArithmeticException (quot 0 0)))
+  
+  (are (= _1 _2)
+    (quot 4 2) 2
+    (quot 3 2) 1
+    (quot 6 4) 1
+    (quot 0 5) 0
+
+    (quot 2 1/2) 4
+    (quot 2/3 1/2) 1
+    (quot 1 2/3) 1
+
+    (quot 4.0 2.0) 2.0
+    (quot 4.5 2.0) 2.0
+
+    ; |num| > |div|, num != k * div
+    (quot 42 5) 8     ; (8 * 5) + 2 == 42
+    (quot 42 -5) -8   ; (-8 * -5) + 2 == 42
+    (quot -42 5) -8   ; (-8 * 5) + -2 == -42
+    (quot -42 -5) 8   ; (8 * -5) + -2 == -42
+
+    ; |num| > |div|, num = k * div
+    (quot 9 3) 3
+    (quot 9 -3) -3
+    (quot -9 3) -3
+    (quot -9 -3) 3
+
+    ; |num| < |div|
+    (quot 2 5) 0
+    (quot 2 -5) 0
+    (quot -2 5) 0
+    (quot -2 -5) 0
+
+    ; num = 0, div != 0
+    (quot 0 3) 0
+    (quot 0 -3) 0
+  )
+)
+
+
+;; *** Predicates ***
 
 ;; pos? zero? neg?