From 31791676501f8a8f9eb0d316a6d841a4c0d6738d Mon Sep 17 00:00:00 2001
From: Ran Benita <ran@unusedvar.com>
Date: Sat, 8 Jun 2024 02:11:20 +0300
Subject: [PATCH] [8.2.x] unittest: fix assertion errors on unittest reruns

---
 changelog/12424.bugfix.rst                            |  1 +
 src/_pytest/unittest.py                               |  2 +-
 .../pytest_rerunfailures_integration.py               | 11 +++++++++++
 tox.ini                                               |  2 +-
 4 files changed, 14 insertions(+), 2 deletions(-)
 create mode 100644 changelog/12424.bugfix.rst
 create mode 100644 testing/plugins_integration/pytest_rerunfailures_integration.py

diff --git a/changelog/12424.bugfix.rst b/changelog/12424.bugfix.rst
new file mode 100644
index 000000000..7ad112685
--- /dev/null
+++ b/changelog/12424.bugfix.rst
@@ -0,0 +1 @@
+Fix crash with `assert testcase is not None` assertion failure when re-running unittest tests using plugins like pytest-rerunfailures. Regressed in 8.2.2.
diff --git a/src/_pytest/unittest.py b/src/_pytest/unittest.py
index baca58bd9..2f3fd5b01 100644
--- a/src/_pytest/unittest.py
+++ b/src/_pytest/unittest.py
@@ -216,7 +216,7 @@ class TestCaseFunction(Function):
             self._explicit_tearDown()
             self._explicit_tearDown = None
         self._obj = None
-        self._instance = None
+        del self._instance
         super().teardown()
 
     def startTest(self, testcase: "unittest.TestCase") -> None:
diff --git a/testing/plugins_integration/pytest_rerunfailures_integration.py b/testing/plugins_integration/pytest_rerunfailures_integration.py
new file mode 100644
index 000000000..9a13a3279
--- /dev/null
+++ b/testing/plugins_integration/pytest_rerunfailures_integration.py
@@ -0,0 +1,11 @@
+import unittest
+
+
+class MyTestCase(unittest.TestCase):
+    first_time = True
+
+    def test_fail_the_first_time(self) -> None:
+        """Regression test for issue #12424."""
+        if self.first_time:
+            type(self).first_time = False
+            self.fail()
diff --git a/tox.ini b/tox.ini
index 30d3e68de..e42c22655 100644
--- a/tox.ini
+++ b/tox.ini
@@ -143,7 +143,7 @@ commands =
     pytest --cov=. simple_integration.py
     pytest --ds=django_settings simple_integration.py
     pytest --html=simple.html simple_integration.py
-    pytest --reruns 5 simple_integration.py
+    pytest --reruns 5 simple_integration.py pytest_rerunfailures_integration.py
     pytest pytest_anyio_integration.py
     pytest pytest_asyncio_integration.py
     pytest pytest_mock_integration.py