avoid helper functions showing up in py.test tracebacks

--HG--
branch : trunk

CHANGELOG

@@ -1,3 +1,9 @@
+Changes between 1.3.0 and 1.3.1
+==================================================
+
+- improve tracebacks showing:
+  - raises shows shorter more relevant tracebacks
+
 Changes between 1.2.1 and 1.3.0
 ==================================================
 

py/_builtin.py

@@ -175,6 +175,7 @@ else:
 
     def exec_(obj, globals=None, locals=None):
         """ minimal backport of py3k exec statement. """ 
+        __tracebackhide__ = True
         if globals is None: 
             frame = sys._getframe(1)
             globals = frame.f_globals 
@@ -187,14 +188,17 @@ else:
 if sys.version_info >= (3,0):
     exec ("""
 def _reraise(cls, val, tb):
+    __tracebackhide__ = True
     assert hasattr(val, '__traceback__')
     raise val
 """)
 else:
     exec ("""
 def _reraise(cls, val, tb):
+    __tracebackhide__ = True
     raise cls, val, tb
 def exec2(obj, globals, locals):
+    __tracebackhide__ = True
     exec obj in globals, locals 
 """)