diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index 7d6db671b..44fc9f259 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -18,9 +18,10 @@
   if a test suite uses ``pytest_plugins`` to load internal plugins (`#1888`_).
   Thanks `@jaraco`_ for the report and `@nicoddemus`_ for the PR (`#1891`_).
 
-* Do not call tearDown (and cleanups) when running unittest with ``--pdb``
+* Do not call tearDown and cleanups when running tests from
+  ``unittest.TestCase`` subclasses with ``--pdb``
   enabled. This allows proper post mortem debugging for all applications
-  which have significant logic in their tearDown method (`#1890`_). Thanks
+  which have significant logic in their tearDown machinery (`#1890`_). Thanks
   `@mbyt`_ for the PR.
 
 *
diff --git a/_pytest/unittest.py b/_pytest/unittest.py
index 5e87441cc..47868f448 100644
--- a/_pytest/unittest.py
+++ b/_pytest/unittest.py
@@ -153,7 +153,7 @@ class TestCaseFunction(pytest.Function):
         if self.config.pluginmanager.get_plugin("pdbinvoke") is None:
             self._testcase(result=self)
         else:
-            # disables tearDown and cleanups for post mortem debugging
+            # disables tearDown and cleanups for post mortem debugging (see #1890)
             self._testcase.debug()
 
 
diff --git a/doc/en/unittest.rst b/doc/en/unittest.rst
index 9e0b4973d..e4c09ee24 100644
--- a/doc/en/unittest.rst
+++ b/doc/en/unittest.rst
@@ -33,6 +33,13 @@ distributing tests to multiple CPUs via the ``-nNUM`` option if you
 installed the ``pytest-xdist`` plugin.  Please refer to
 the general ``pytest`` documentation for many more examples.
 
+.. note::
+
+    Running tests from ``unittest.TestCase`` subclasses with ``--pdb`` will
+    disable tearDown and cleanup methods for the case that an Exception is
+    occurs. This allows proper post mortem debugging for all applications
+    which have significant logic in their tearDown machinery.
+
 Mixing pytest fixtures into unittest.TestCase style tests
 -----------------------------------------------------------
 
diff --git a/testing/test_pdb.py b/testing/test_pdb.py
index a0fbc473e..d79d71262 100644
--- a/testing/test_pdb.py
+++ b/testing/test_pdb.py
@@ -86,7 +86,7 @@ class TestPDB:
                 def tearDown(self):
                     self.filename = None
                 def test_false(self):
-                    self.filename = 'bla' + '.txt'
+                    self.filename = 'debug' + '.me'
                     assert 0
         """)
         child = testdir.spawn_pytest("--pdb %s" % p1)
@@ -94,7 +94,7 @@ class TestPDB:
         child.sendline('p self.filename')
         child.sendeof()
         rest = child.read().decode("utf8")
-        assert 'bla.txt' in rest
+        assert 'debug.me' in rest
         if child.isalive():
             child.wait()