# HG changeset patch
# User Julien Cristau <julien.cristau@logilab.fr>
# Date 1456388901 -3600
# Node ID e7514e949ad8f82022fac11cd0b18c61ccac9e98
# Parent  81fce01b4cc00a314e4198005bf34f5f90579a9f
[entity] comparing two entities returns NotImplemented

Fixes a test when using some versions of unittest2, where
assertItemsEqual tries a sort and expects TypeError, which it doesn't
get if we directly raise NotImplementedError.  The NotImplemented value
is treated specially by the interpreter:
https://docs.python.org/3.4/library/constants.html#NotImplemented

diff -r 81fce01b4cc0 -r e7514e949ad8 cubicweb/entity.py
--- a/cubicweb/entity.py	Thu Feb 18 09:24:43 2016 +0100
+++ b/cubicweb/entity.py	Thu Feb 25 09:28:21 2016 +0100
@@ -547,7 +547,7 @@
             self.e_schema, self.eid, list(self.cw_attr_cache), id(self))
 
     def __lt__(self, other):
-        raise NotImplementedError('comparison not implemented for %s' % self.__class__)
+        return NotImplemented
 
     def __eq__(self, other):
         if isinstance(self.eid, integer_types):