unittest: do not use TestCase.debug() with --pdb

Fixes pytest-dev#5991.

Author: blueyed

changelog/5991.bugfix.rst

@@ -0,0 +1 @@
+Fix interaction with ``--pdb`` and unittests: do not use unittest's ``TestCase.debug()``.

doc/en/unittest.rst

@@ -238,17 +238,6 @@ was executed ahead of the ``test_method``.
 
 .. _pdb-unittest-note:
 
-.. note::
-
-    Running tests from ``unittest.TestCase`` subclasses with ``--pdb`` will
-    disable tearDown and cleanup methods for the case that an Exception
-    occurs. This allows proper post mortem debugging for all applications
-    which have significant logic in their tearDown machinery. However,
-    supporting this feature has the following side effect: If people
-    overwrite ``unittest.TestCase`` ``__call__`` or ``run``, they need to
-    to overwrite ``debug`` in the same way  (this is also true for standard
-    unittest).
-
 .. note::
 
     Due to architectural differences between the two frameworks, setup and

src/_pytest/unittest.py

@@ -187,29 +187,8 @@ def addSuccess(self, testcase):
     def stopTest(self, testcase):
         pass
 
-    def _handle_skip(self):
-        # implements the skipping machinery (see #2137)
-        # analog to pythons Lib/unittest/case.py:run
-        testMethod = getattr(self._testcase, self._testcase._testMethodName)
-        if getattr(self._testcase.__class__, "__unittest_skip__", False) or getattr(
-            testMethod, "__unittest_skip__", False
-        ):
-            # If the class or method was skipped.
-            skip_why = getattr(
-                self._testcase.__class__, "__unittest_skip_why__", ""
-            ) or getattr(testMethod, "__unittest_skip_why__", "")
-            self._testcase._addSkip(self, self._testcase, skip_why)
-            return True
-        return False
-
     def runtest(self):
-        if self.config.pluginmanager.get_plugin("pdbinvoke") is None:
-            self._testcase(result=self)
-        else:
-            # disables tearDown and cleanups for post mortem debugging (see #1890)
-            if self._handle_skip():
-                return
-            self._testcase.debug()
+        self._testcase(result=self)
 
     def _prunetraceback(self, excinfo):
         Function._prunetraceback(self, excinfo)

testing/test_pdb.py

@@ -164,20 +164,32 @@ def test_pdb_unittest_postmortem(self, testdir):
         p1 = testdir.makepyfile(
             """
             import unittest
+
+            teardown_called = 0
+
             class Blub(unittest.TestCase):
                 def tearDown(self):
-                    self.filename = None
-                def test_false(self):
+                    global teardown_called
+                    teardown_called += 1
+
+                def test_error(self):
+                    assert teardown_called == 0
                     self.filename = 'debug' + '.me'
                     assert 0
+
+                def test_check(self):
+                    assert teardown_called == 1
         """
         )
-        child = testdir.spawn_pytest("--pdb %s" % p1)
+        child = testdir.spawn_pytest(
+            "--pdb {p1}::Blub::test_error {p1}::Blub::test_check".format(p1=p1)
+        )
         child.expect("Pdb")
-        child.sendline("p self.filename")
-        child.sendeof()
+        child.sendline("p 'filename=' + self.filename")
+        child.expect("'filename=debug.me'")
+        child.sendline("c")
         rest = child.read().decode("utf8")
-        assert "debug.me" in rest
+        assert "= 1 failed, 1 passed in" in rest
         self.flush(child)
 
     def test_pdb_unittest_skip(self, testdir):