Add the new test in the list of tests

Author: jkseppan

lib/matplotlib/__init__.py

@@ -1321,6 +1321,7 @@ def tk_window_focus():
     'matplotlib.tests.test_artist',
     'matplotlib.tests.test_axes',
     'matplotlib.tests.test_axes_grid1',
+    'matplotlib.tests.test_backend_bases',
     'matplotlib.tests.test_backend_pdf',
     'matplotlib.tests.test_backend_pgf',
     'matplotlib.tests.test_backend_ps',