From 2f993af54a1401460cc0f70915f28251f007344d Mon Sep 17 00:00:00 2001
From: Thomas Hisch <t.hisch@gmail.com>
Date: Sun, 29 Oct 2017 19:37:01 +0000
Subject: [PATCH] Fix context output handling for doctests

Show full context of doctest source in the pytest output, if the lineno of
failed example in the docstring is < 9.
---
 _pytest/doctest.py      |  2 +-
 changelog/2882.bugfix   |  1 +
 testing/test_doctest.py | 30 ++++++++++++++++++++++++++++--
 3 files changed, 30 insertions(+), 3 deletions(-)
 create mode 100644 changelog/2882.bugfix

diff --git a/_pytest/doctest.py b/_pytest/doctest.py
index cc505c8d0..4c05acddf 100644
--- a/_pytest/doctest.py
+++ b/_pytest/doctest.py
@@ -120,7 +120,7 @@ class DoctestItem(pytest.Item):
                 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]
+                lines = lines[max(example.lineno - 9, 0):example.lineno + 1]
             else:
                 lines = ['EXAMPLE LOCATION UNKNOWN, not showing all tests of that example']
                 indent = '>>>'
diff --git a/changelog/2882.bugfix b/changelog/2882.bugfix
new file mode 100644
index 000000000..2bda24c01
--- /dev/null
+++ b/changelog/2882.bugfix
@@ -0,0 +1 @@
+Show full context of doctest source in the pytest output, if the lineno of failed example in the docstring is < 9.
\ No newline at end of file
diff --git a/testing/test_doctest.py b/testing/test_doctest.py
index 8a81ea0ed..6616d2eae 100644
--- a/testing/test_doctest.py
+++ b/testing/test_doctest.py
@@ -173,7 +173,7 @@ class TestDoctests(object):
             "*UNEXPECTED*ZeroDivision*",
         ])
 
-    def test_docstring_context_around_error(self, testdir):
+    def test_docstring_partial_context_around_error(self, testdir):
         """Test that we show some context before the actual line of a failing
         doctest.
         """
@@ -199,7 +199,7 @@ class TestDoctests(object):
         ''')
         result = testdir.runpytest('--doctest-modules')
         result.stdout.fnmatch_lines([
-            '*docstring_context_around_error*',
+            '*docstring_partial_context_around_error*',
             '005*text-line-3',
             '006*text-line-4',
             '013*text-line-11',
@@ -213,6 +213,32 @@ class TestDoctests(object):
         assert 'text-line-2' not in result.stdout.str()
         assert 'text-line-after' not in result.stdout.str()
 
+    def test_docstring_full_context_around_error(self, testdir):
+        """Test that we show the whole context before the actual line of a failing
+        doctest, provided that the context is up to 10 lines long.
+        """
+        testdir.makepyfile('''
+            def foo():
+                """
+                text-line-1
+                text-line-2
+
+                >>> 1 + 1
+                3
+                """
+        ''')
+        result = testdir.runpytest('--doctest-modules')
+        result.stdout.fnmatch_lines([
+            '*docstring_full_context_around_error*',
+            '003*text-line-1',
+            '004*text-line-2',
+            '006*>>> 1 + 1',
+            'Expected:',
+            '    3',
+            'Got:',
+            '    2',
+        ])
+
     def test_doctest_linedata_missing(self, testdir):
         testdir.tmpdir.join('hello.py').write(_pytest._code.Source("""
             class Fun(object):