Fix unicode issue while running doctests in Python 2

Fix pytest-dev#2434

CHANGELOG.rst

@@ -1,7 +1,9 @@
 3.1.1 (unreleased)
 ==================
 
-* Fix encoding errors for unicode warnings in Python 2.
+* Fix encoding errors for unicode warnings in Python 2. (towncrier: 2436.bugfix)
+
+* Fix issue with non-ascii contents in doctest text files. (towncrier: 2434.bugfix)
 
 
 3.1.0 (2017-05-22)

_pytest/doctest.py

@@ -181,6 +181,7 @@ def collect(self):
         optionflags = get_optionflags(self)
         runner = doctest.DebugRunner(verbose=0, optionflags=optionflags,
                                      checker=_get_checker())
+        _fix_spoof_python2(runner, encoding)
 
         parser = doctest.DocTestParser()
         test = parser.get_doctest(text, globs, name, filename, 0)
@@ -216,6 +217,10 @@ def collect(self):
         optionflags = get_optionflags(self)
         runner = doctest.DebugRunner(verbose=0, optionflags=optionflags,
                                      checker=_get_checker())
+
+        encoding = self.config.getini("doctest_encoding")
+        _fix_spoof_python2(runner, encoding)
+
         for test in finder.find(module, module.__name__):
             if test.examples:  # skip empty doctests
                 yield DoctestItem(test.name, self, runner, test)
@@ -324,6 +329,30 @@ def _get_report_choice(key):
         DOCTEST_REPORT_CHOICE_NONE: 0,
     }[key]
 
+
+def _fix_spoof_python2(runner, encoding):
+    """
+    Installs a "SpoofOut" into the given DebugRunner so it properly deals with unicode output.
+    
+    This fixes the problem related in issue #2434.
+    """
+    from _pytest.compat import _PY2
+    if not _PY2:
+        return
+
+    from doctest import _SpoofOut
+
+    class UnicodeSpoof(_SpoofOut):
+
+        def getvalue(self):
+            result = _SpoofOut.getvalue(self)
+            if encoding:
+                result = result.decode(encoding)
+            return result
+
+    runner._fakeout = UnicodeSpoof()
+
+
 @pytest.fixture(scope='session')
 def doctest_namespace():
     """

testing/test_doctest.py

@@ -505,6 +505,28 @@ def foo():
                                     "--junit-xml=junit.xml")
         reprec.assertoutcome(failed=1)
 
+    def test_unicode_doctest(self, testdir):
+        """
+        Test case for issue 2434: DecodeError on Python 2 when doctest contains non-ascii
+        characters.
+        """
+        p = testdir.maketxtfile(test_unicode_doctest="""
+            .. doctest::
+
+                >>> print(
+                ...    "Hi\\n\\nByé")
+                Hi
+                ...
+                Byé
+                >>> 1/0  # Byé
+                1
+        """)
+        result = testdir.runpytest(p)
+        result.stdout.fnmatch_lines([
+            '*UNEXPECTED EXCEPTION: ZeroDivisionError*',
+            '*1 failed*',
+        ])
+
 
 class TestLiterals(object):