Handle import errors with non-ascii messages when importing plugins

Fix pytest-dev#1998

CHANGELOG.rst

@@ -6,14 +6,16 @@
 * Import errors when collecting test modules now display the full traceback (`#1976`_).
   Thanks `@cwitty`_ for the report and `@nicoddemus`_ for the PR.
 
-*
+* When loading plugins, import errors which contain non-ascii messages are now properly handled in Python 2 (`#1998`_).
+  Thanks `@nicoddemus`_ for the PR.
 
 *
 
 
 .. _@cwitty: https://github.com/cwitty
 
 .. _#1976: https://github.com/pytest-dev/pytest/issues/1976
+.. _#1998: https://github.com/pytest-dev/pytest/issues/1998
 
 
 

_pytest/compat.py

@@ -213,4 +213,18 @@ def _is_unittest_unexpected_success_a_failure():
         Changed in version 3.4: Returns False if there were any
         unexpectedSuccesses from tests marked with the expectedFailure() decorator.
     """
-    return sys.version_info >= (3, 4)
+    return sys.version_info >= (3, 4)
+
+
+if _PY3:
+    def safe_str(v):
+        """returns v as string"""
+        return str(v)
+else:
+    def safe_str(v):
+        """returns v as string, converting to ascii if necessary"""
+        try:
+            return str(v)
+        except UnicodeError:
+            errors = 'replace'
+            return v.encode('ascii', errors)

_pytest/config.py

@@ -12,6 +12,7 @@
 import _pytest.hookspec  # the extension point definitions
 import _pytest.assertion
 from _pytest._pluggy import PluginManager, HookimplMarker, HookspecMarker
+from _pytest.compat import safe_str
 
 hookimpl = HookimplMarker("pytest")
 hookspec = HookspecMarker("pytest")
@@ -405,7 +406,7 @@ def import_plugin(self, modname):
         try:
             __import__(importspec)
         except ImportError as e:
-            new_exc = ImportError('Error importing plugin "%s": %s' % (modname, e))
+            new_exc = ImportError('Error importing plugin "%s": %s' % (modname, safe_str(e)))
             # copy over name and path attributes
             for attr in ('name', 'path'):
                 if hasattr(e, attr):

testing/test_pluginmanager.py

@@ -1,3 +1,4 @@
+# encoding: UTF-8
 import pytest
 import py
 import os
@@ -179,15 +180,20 @@ def test_default_markers(testdir):
     ])
 
 
-def test_importplugin_issue375(testdir, pytestpm):
+def test_importplugin_error_message(testdir, pytestpm):
     """Don't hide import errors when importing plugins and provide
     an easy to debug message.
+
+    See #375 and #1998.
     """
     testdir.syspathinsert(testdir.tmpdir)
-    testdir.makepyfile(qwe="import aaaa")
+    testdir.makepyfile(qwe="""
+        # encoding: UTF-8
+        raise ImportError('Not possible to import: ☺')
+    """)
     with pytest.raises(ImportError) as excinfo:
         pytestpm.import_plugin("qwe")
-    expected = '.*Error importing plugin "qwe": No module named \'?aaaa\'?'
+    expected = '.*Error importing plugin "qwe": Not possible to import: .'
     assert py.std.re.match(expected, str(excinfo.value))