testlib: ensure DocTest does not alter __builtins__

The DocTest Safety seems to fails and we need our own overlay. Maybe we are
using it wrong?

2 files changed, 9 insertions, 2 deletions

diff --git a/ChangeLog b/ChangeLog
index eb43a1d..108f346 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -3,7 +3,7 @@ ChangeLog for logilab.common
 
 	--
     * new `registry` module containing a backport of CubicWeb selectable objects registry (closes #84654)
-
+    * testlib: DocTestCase fix builtins pollution after doctest execution.
 
 2011-10-28  --  0.57.1
     * daemon: change $HOME after dropping privileges (closes #81297)
diff --git a/testlib.py b/testlib.py
index da49387..ca452ca 100644
--- a/testlib.py
+++ b/testlib.py
@@ -1214,7 +1214,14 @@ class DocTest(TestCase):
                 suite = doctest.DocTestSuite(self.module)
         except AttributeError:
             suite = SkippedSuite()
-        return suite.run(result)
+        # doctest may gork the builtins dictionnary
+        # This happen to the "_" entry used by gettext
+        old_builtins =  __builtins__.copy()
+        try:
+            return suite.run(result)
+        finally:
+            __builtins__.clear()
+            __builtins__.update(old_builtins)
     run = __call__
 
     def test(self):