Add some numeric tests

[SVN r7984]

test_extclass.py

@@ -264,6 +264,18 @@ Sequence tests:
     >>> map(lambda x:x, Range(3, 10)[0:4])
     [3, 4, 5, 6]
 
+Numeric tests:
+    >>> x = Rational(2,3)
+    >>> y = Rational(1,4)
+    >>> print x + y
+    11/12
+    >>> print x - y
+    5/12
+    >>> print x * y
+    1/6
+    >>> print x / y
+    8/3
+    
 delete non-existent attribute:
     del m.foobar
     Traceback (innermost last):
@@ -412,6 +424,7 @@ Testing __call__:
     0
     >>> comparator(couple2, couple)
     1
+
 '''
 
 from demo import *