From eddd087e23354805ea2f6fededd8e5b40a355295 Mon Sep 17 00:00:00 2001
From: Bruno Oliveira <nicoddemus@gmail.com>
Date: Thu, 4 Oct 2018 20:19:40 -0300
Subject: [PATCH 1/2] Fix TestCase.debug() when used to call test methods with
 subtests

Fixes bpo-34900
---
 Lib/unittest/case.py                               |  2 +-
 Lib/unittest/test/test_case.py                     | 14 ++++++++++++++
 .../2018-10-05-05-55-53.bpo-34900.8RNiFu.rst       |  2 ++
 3 files changed, 17 insertions(+), 1 deletion(-)
 create mode 100644 Misc/NEWS.d/next/Library/2018-10-05-05-55-53.bpo-34900.8RNiFu.rst

diff --git a/Lib/unittest/case.py b/Lib/unittest/case.py
index 1faa6b641f2d755..2579c30474b5366 100644
--- a/Lib/unittest/case.py
+++ b/Lib/unittest/case.py
@@ -514,7 +514,7 @@ def subTest(self, msg=_subtest_msg_sentinel, **params):
         case as failed but resumes execution at the end of the enclosed
         block, allowing further test code to be executed.
         """
-        if not self._outcome.result_supports_subtests:
+        if self._outcome is None or not self._outcome.result_supports_subtests:
             yield
             return
         parent = self._subtest
diff --git a/Lib/unittest/test/test_case.py b/Lib/unittest/test/test_case.py
index baabddd06f41a41..687fe5b65f109e7 100644
--- a/Lib/unittest/test/test_case.py
+++ b/Lib/unittest/test/test_case.py
@@ -425,6 +425,20 @@ def test_c(self):
         expected = ['a1', 'a2', 'b1']
         self.assertEqual(events, expected)
 
+    def test_subtests_debug(self):
+        # Test debug() with a test that uses subTest() (bpo-34900)
+        events = []
+
+        class Foo(unittest.TestCase):
+            def test_a(self):
+                events.append('test case')
+                with self.subTest():
+                    events.append('subtest 1')
+
+        Foo('test_a').debug()
+
+        self.assertEqual(events, ['test case', 'subtest 1'])
+
     # "This class attribute gives the exception raised by the test() method.
     # If a test framework needs to use a specialized exception, possibly to
     # carry additional information, it must subclass this exception in
diff --git a/Misc/NEWS.d/next/Library/2018-10-05-05-55-53.bpo-34900.8RNiFu.rst b/Misc/NEWS.d/next/Library/2018-10-05-05-55-53.bpo-34900.8RNiFu.rst
new file mode 100644
index 000000000000000..df86ca5ad053141
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2018-10-05-05-55-53.bpo-34900.8RNiFu.rst
@@ -0,0 +1,2 @@
+Fixed ``TestCase.debug()`` when used to call test methods with subtests.
+Patch by Bruno Oliveira.

From bb8a047cb834b3b3c13a6f6ebeba6203ba09330d Mon Sep 17 00:00:00 2001
From: Berker Peksag <berker.peksag@gmail.com>
Date: Fri, 5 Oct 2018 12:28:23 +0300
Subject: [PATCH 2/2] markup

---
 .../next/Library/2018-10-05-05-55-53.bpo-34900.8RNiFu.rst     | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Misc/NEWS.d/next/Library/2018-10-05-05-55-53.bpo-34900.8RNiFu.rst b/Misc/NEWS.d/next/Library/2018-10-05-05-55-53.bpo-34900.8RNiFu.rst
index df86ca5ad053141..20e3a0e2d5a19b6 100644
--- a/Misc/NEWS.d/next/Library/2018-10-05-05-55-53.bpo-34900.8RNiFu.rst
+++ b/Misc/NEWS.d/next/Library/2018-10-05-05-55-53.bpo-34900.8RNiFu.rst
@@ -1,2 +1,2 @@
-Fixed ``TestCase.debug()`` when used to call test methods with subtests.
-Patch by Bruno Oliveira.
+Fixed :meth:`unittest.TestCase.debug` when used to call test methods with
+subtests.  Patch by Bruno Oliveira.