Fix decode error in Python 2.7 when docstrings contain a non-ascii character

Fix #628

CHANGELOG

@@ -19,6 +19,9 @@
   properly displayed.
   Thanks Ionel Maries Cristian for the report and Bruno Oliveira for the PR.
 
+- fix #628: fixed internal UnicodeDecodeError when doctests contain unicode.
+  Thanks Jason R. Coombs for the report and Bruno Oliveira for the PR.
+
 
 2.8.5
 -----

_pytest/doctest.py

@@ -81,15 +81,15 @@ class DoctestItem(pytest.Item):
             reprlocation = ReprFileLocation(filename, lineno, message)
             checker = _get_unicode_checker()
             REPORT_UDIFF = doctest.REPORT_UDIFF
-            filelines = py.path.local(filename).readlines(cr=0)
-            lines = []
             if lineno is not None:
-                i = max(test.lineno, max(0, lineno - 10)) # XXX?
-                for line in filelines[i:lineno]:
-                    lines.append("%03d %s" % (i+1, line))
-                    i += 1
+                lines = doctestfailure.test.docstring.splitlines(False)
+                # add line numbers to the left of the error message
+                lines = ["%03d %s" % (i + test.lineno + 1, x)
+                         for (i, x) in enumerate(lines)]
+                # trim docstring error lines to 10
+                lines = lines[example.lineno - 9:example.lineno + 1]
             else:
-                lines.append('EXAMPLE LOCATION UNKNOWN, not showing all tests of that example')
+                lines = ['EXAMPLE LOCATION UNKNOWN, not showing all tests of that example']
                 indent = '>>>'
                 for line in example.source.splitlines():
                     lines.append('??? %s %s' % (indent, line))

testing/test_doctest.py

@@ -1,3 +1,4 @@
+# encoding: utf-8
 import sys
 from _pytest.doctest import DoctestItem, DoctestModule, DoctestTextfile
 import py
@@ -109,6 +110,46 @@ class TestDoctests:
             "*UNEXPECTED*ZeroDivision*",
         ])
 
+    def test_docstring_context_around_error(self, testdir):
+        """Test that we show some context before the actual line of a failing
+        doctest.
+        """
+        testdir.makepyfile('''
+            def foo():
+                """
+                text-line-1
+                text-line-2
+                text-line-3
+                text-line-4
+                text-line-5
+                text-line-6
+                text-line-7
+                text-line-8
+                text-line-9
+                text-line-10
+                text-line-11
+                >>> 1 + 1
+                3
+
+                text-line-after
+                """
+        ''')
+        result = testdir.runpytest('--doctest-modules')
+        result.stdout.fnmatch_lines([
+            '*docstring_context_around_error*',
+            '005*text-line-3',
+            '006*text-line-4',
+            '013*text-line-11',
+            '014*>>> 1 + 1',
+            'Expected:',
+            '    3',
+            'Got:',
+            '    2',
+        ])
+        # lines below should be trimmed out
+        assert 'text-line-2' not in result.stdout.str()
+        assert 'text-line-after' not in result.stdout.str()
+
     def test_doctest_linedata_missing(self, testdir):
         testdir.tmpdir.join('hello.py').write(py.code.Source("""
             class Fun(object):
@@ -339,6 +380,23 @@ class TestDoctests:
         reprec = testdir.inline_run(p, "--doctest-glob=x*.txt")
         reprec.assertoutcome(failed=1, passed=0)
 
+    def test_contains_unicode(self, testdir):
+        """Fix internal error with docstrings containing non-ascii characters.
+        """
+        testdir.makepyfile(u'''
+            # encoding: utf-8
+            def foo():
+                """
+                >>> name = 'с' # not letter 'c' but instead Cyrillic 's'.
+                'anything'
+                """
+        ''')
+        result = testdir.runpytest('--doctest-modules')
+        result.stdout.fnmatch_lines([
+            'Got nothing',
+            '* 1 failed in*',
+        ])
+
     def test_ignore_import_errors_on_doctest(self, testdir):
         p = testdir.makepyfile("""
             import asdf
@@ -579,4 +637,4 @@ class TestDoctestAutoUseFixtures:
         """)
         result = testdir.runpytest('--doctest-modules')
         assert 'FAILURES' not in str(result.stdout.str())
-        result.stdout.fnmatch_lines(['*=== 1 passed in *'])
+        result.stdout.fnmatch_lines(['*=== 1 passed in *'])