diff --git a/flake8/tests/test_warnings.py b/flake8/tests/test_warnings.py
index 9dca44b..71b36f1 100644
--- a/flake8/tests/test_warnings.py
+++ b/flake8/tests/test_warnings.py
@@ -9,6 +9,8 @@
     tests (nosetests --with-isolation doesn't help).
 
     In tox.ini, these tests are run separately.
+
+    See https://gitlab.com/pycqa/flake8/issues/44 for an explanation.
 """
 
 from __future__ import with_statement
diff --git a/tox.ini b/tox.ini
index d26d358..73bec1f 100644
--- a/tox.ini
+++ b/tox.ini
@@ -7,9 +7,11 @@ envlist =
 usedevelop = True
 deps =
     mock
+    nose
 commands =
     python setup.py test -q
     python setup.py flake8
+    nosetests flake8.tests._test_warnings
 
 [testenv:py27-flake8]
 basepython = python2.7