Remove UnicodeWarning from pytest warnings

Fix #2463

Author: nicoddemus

_pytest/warnings.py

@@ -63,23 +63,15 @@ def catch_warnings_for_item(item):
 
         for warning in log:
             warn_msg = warning.message
-            unicode_warning = False
 
             if compat._PY2 and any(isinstance(m, compat.UNICODE_TYPES) for m in warn_msg.args):
                 warn_msg.args = [compat.safe_str(m) for m in warn_msg.args]
-                unicode_warning = True
 
             msg = warnings.formatwarning(
                 warn_msg, warning.category,
                 warning.filename, warning.lineno, warning.line)
             item.warn("unused", msg)
 
-            if unicode_warning:
-                warnings.warn(
-                    "This warning %s is broken as it's message is not a str instance"
-                    "(after all this is a stdlib problem workaround)" % msg,
-                    UnicodeWarning)
-
 
 @pytest.hookimpl(hookwrapper=True)
 def pytest_runtest_protocol(item):

changelog/2463.bugfix

@@ -0,0 +1 @@
+Remove ``UnicodeWarning`` issued from the internal pytest warnings plugin when a captured warning contains a unicode message.

testing/test_warnings.py

@@ -1,8 +1,6 @@
 # -*- coding: utf8 -*-
 from __future__ import unicode_literals
 
-import sys
-
 import pytest
 
 
@@ -112,9 +110,6 @@ def test_ignore(testdir, pyfile_with_warnings, method):
     assert WARNINGS_SUMMARY_HEADER not in result.stdout.str()
 
 
-
-@pytest.mark.skipif(sys.version_info < (3, 0),
-                    reason='warnings message is unicode is ok in python3')
 def test_unicode(testdir, pyfile_with_warnings):
     testdir.makepyfile('''
         # -*- coding: utf8 -*-
@@ -138,34 +133,6 @@ def test_func(fix):
     ])
 
 
-@pytest.mark.skipif(sys.version_info >= (3, 0),
-                    reason='warnings message is broken as it is not str instance')
-def test_py2_unicode(testdir, pyfile_with_warnings):
-    testdir.makepyfile('''
-        # -*- coding: utf8 -*-
-        import warnings
-        import pytest
-
-
-        @pytest.fixture
-        def fix():
-            warnings.warn(u"测试")
-            yield
-
-        def test_func(fix):
-            pass
-    ''')
-    result = testdir.runpytest()
-    result.stdout.fnmatch_lines([
-        '*== %s ==*' % WARNINGS_SUMMARY_HEADER,
-
-        '*test_py2_unicode.py:8: UserWarning: \u6d4b\u8bd5',
-        '*warnings.warn(u"\u6d4b\u8bd5")',
-        '*warnings.py:*: UnicodeWarning: This warning*\u6d4b\u8bd5',
-        '* 1 passed, 2 warnings*',
-    ])
-
-
 def test_works_with_filterwarnings(testdir):
     """Ensure our warnings capture does not mess with pre-installed filters (#2430)."""
     testdir.makepyfile('''