Fix encoding errors for parametrized tests with unicode parameters in py2

Fix #1085

_pytest/python.py

@@ -1093,7 +1093,7 @@ def _idval(val, argname, idx, idfn):
         # convertible to ascii, return it as an str() object instead
         try:
             return str(val)
-        except UnicodeDecodeError:
+        except UnicodeError:
             # fallthrough
             pass
     return str(argname)+str(idx)

testing/python/metafunc.py

@@ -1,3 +1,4 @@
+# -*- coding: utf-8 -*-
 import re
 
 import pytest, py
@@ -118,6 +119,24 @@ class TestMetafunc:
         assert metafunc._calls[2].id == "x1-a"
         assert metafunc._calls[3].id == "x1-b"
 
+    @pytest.mark.skipif('sys.version_info[0] >= 3')
+    def test_unicode_idval_python2(self):
+        """unittest for the expected behavior to obtain ids for parametrized
+        unicode values in Python 2: if convertible to ascii, they should appear
+        as ascii values, otherwise fallback to hide the value behind the name
+        of the parametrized variable name. #1086
+        """
+        from _pytest.python import _idval
+        values = [
+            (u'', ''),
+            (u'ascii', 'ascii'),
+            (u'ação', 'a6'),
+            (u'josé@blah.com', 'a6'),
+            (u'δοκ.ιμή@παράδειγμα.δοκιμή', 'a6'),
+        ]
+        for val, expected in values:
+            assert _idval(val, 'a', 6, None) == expected
+
     @pytest.mark.issue250
     def test_idmaker_autoname(self):
         from _pytest.python import idmaker