Fix #720: nose with detailed errors raises encoding error

In this case, the exception vector being passed in was a string that
contained encoded UTF-8 sequences.  It was being converted to unicode
implicitly, which was raising a UnicodeDecodeError because some bytes
were >= 128.  Make sure the exception string is converted to unicode
before trying to put the whole thing together.

Thanks to Guillaume Ayoub for the test case.

3 files changed, 25 insertions, 3 deletions

diff --git a/functional_tests/support/issue720/test.py b/functional_tests/support/issue720/test.py
new file mode 100644
index 0000000..0a194fd
--- /dev/null
+++ b/functional_tests/support/issue720/test.py
@@ -0,0 +1,6 @@
+# -*- coding: utf-8 -*-
+import unittest
+class Test(unittest.TestCase):
+    def test(self):
+        print u"Unicöde"
+        assert 1 == 2
diff --git a/functional_tests/test_failuredetail_plugin.py b/functional_tests/test_failuredetail_plugin.py
index 284cf49..8484461 100644
--- a/functional_tests/test_failuredetail_plugin.py
+++ b/functional_tests/test_failuredetail_plugin.py
@@ -46,5 +46,19 @@ class TestFailureDetailWithCapture(PluginTester, unittest.TestCase):
 
         assert expect in self.output
 
+class TestFailureDetailWithUnicodeAndCapture(PluginTester, unittest.TestCase):
+    activate = "-d"
+    args = ['-v']
+    plugins = [FailureDetail(), Capture()]
+    suitepath = os.path.join(support, 'issue720')
+
+    def runTest(self):
+        print '*' * 70
+        print str(self.output)
+        print '*' * 70
+
+        assert 'UnicodeDecodeError' not in self.output
+        assert 'UnicodeEncodeError' not in self.output
+
 if __name__ == '__main__':
     unittest.main()
diff --git a/nose/plugins/failuredetail.py b/nose/plugins/failuredetail.py
index 4c0729c..6462865 100644
--- a/nose/plugins/failuredetail.py
+++ b/nose/plugins/failuredetail.py
@@ -7,6 +7,7 @@ debugging information.
 """
     
 from nose.plugins import Plugin
+from nose.pyversion import exc_to_unicode, force_unicode
 from nose.inspector import inspect_traceback
 
 class FailureDetail(Plugin):
@@ -38,10 +39,11 @@ class FailureDetail(Plugin):
         """Add detail from traceback inspection to error message of a failure.
         """
         ec, ev, tb = err
-        tbinfo, str_ev = None, str(ev)
+        tbinfo, str_ev = None, exc_to_unicode(ev)
+
         if tb:
-            tbinfo = inspect_traceback(tb)
-            str_ev = '\n'.join([str(ev), tbinfo])
+            tbinfo = force_unicode(inspect_traceback(tb))
+            str_ev = '\n'.join([str_ev, tbinfo])
         test.tbinfo = tbinfo
         return (ec, str_ev, tb)