# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1481374964 -3600
# Node ID 32942668c75caeace7969d1246450aa35160a36c
# Parent  0978d9f032c93009afb36101621b9dc3fe4dd6ba
Handle TypeError, not AttributeError, when operations are not found on operands.
Added testing of operator methods in new classes.

diff -r 0978d9f032c9 -r 32942668c75c lib/operator/core.py
--- a/lib/operator/core.py	Sat Dec 10 00:56:32 2016 +0100
+++ b/lib/operator/core.py	Sat Dec 10 14:02:44 2016 +0100
@@ -37,7 +37,7 @@
 
     try:
         fn = left_accessor(a)
-    except AttributeError:
+    except TypeError:
         pass
     else:
         result = fn(b)
@@ -49,7 +49,7 @@
 
     try:
         fn = right_accessor(b)
-    except AttributeError:
+    except TypeError:
         pass
     else:
         result = fn(a)
@@ -76,7 +76,7 @@
 
     try:
         fn = accessor(a)
-    except AttributeError:
+    except TypeError:
         pass
     else:
         result = fn()
@@ -106,7 +106,7 @@
 
     try:
         fn = augmented_accessor(a)
-    except AttributeError:
+    except TypeError:
         pass
     else:
         result = fn(b)
diff -r 0978d9f032c9 -r 32942668c75c tests/operator_support.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tests/operator_support.py	Sat Dec 10 14:02:44 2016 +0100
@@ -0,0 +1,28 @@
+class A:
+    def __init__(self, x):
+        self.x = x
+    def __sub__(self, other):
+        return self.x - other.x
+
+class B:
+    def __init__(self, x):
+        self.x = x
+    def __rsub__(self, other):
+        return other.x - self.x
+
+class C:
+    def __init__(self, x):
+        self.x = x
+
+a = A(10)
+b = B(5)
+c = C(3)
+
+print a - b                         # 5
+print c - b                         # -2
+print a - c                         # 7
+
+try:
+    print b - c                     # should raise an exception
+except TypeError:
+    print "b - c: b and c do not respectively support the __sub__ and __rsub__ operations"