Port exception_to_str() to Python 3

On Python 3, exception messages are unicode strings. There is no need to
decode them.

Skip the test on the "ignore" error handler on Python 3, it's specific
to Python 2.

Change-Id: Ieec9e1e1f7a0fc901271fd74eca357fe1cf6a975

2 files changed, 13 insertions, 4 deletions

diff --git a/glance_store/common/utils.py b/glance_store/common/utils.py
index 48618dc..47571c0 100644
--- a/glance_store/common/utils.py
+++ b/glance_store/common/utils.py
@@ -150,4 +150,6 @@ def exception_to_str(exc):
         except UnicodeError:
             error = ("Caught '%(exception)s' exception." %
                      {"exception": exc.__class__.__name__})
-    return encodeutils.safe_encode(error, errors='ignore')
+    if six.PY2:
+        error = encodeutils.safe_encode(error, errors='ignore')
+    return error
diff --git a/tests/unit/test_utils.py b/tests/unit/test_utils.py
index 6bfb089..e3a4042 100644
--- a/tests/unit/test_utils.py
+++ b/tests/unit/test_utils.py
@@ -14,6 +14,7 @@
 #    under the License.
 
 from oslotest import base
+import six
 
 from glance_store.common import utils
 
@@ -29,9 +30,15 @@ class TestUtils(base.BaseTestCase):
         ret = utils.exception_to_str(Exception('error message'))
         self.assertEqual(ret, 'error message')
 
-        ret = utils.exception_to_str(Exception('\xa5 error message'))
-        self.assertEqual(ret, ' error message')
-
         ret = utils.exception_to_str(FakeException('\xa5 error message'))
         self.assertEqual(ret, "Caught '%(exception)s' exception." %
                          {'exception': 'FakeException'})
+
+    def test_exception_to_str_ignore(self):
+        if six.PY3:
+            # On Python 3, exception messages are unicode strings, they are not
+            # decoded from an encoding and so it's not possible to test the
+            # "ignore" error handler
+            self.skipTest("test specific to Python 2")
+        ret = utils.exception_to_str(Exception('\xa5 error message'))
+        self.assertEqual(ret, ' error message')