convert old fail* assertions to assert*
diff --git a/Lib/importlib/test/import_/test_packages.py b/Lib/importlib/test/import_/test_packages.py
index 5912c1f..b41c36f 100644
--- a/Lib/importlib/test/import_/test_packages.py
+++ b/Lib/importlib/test/import_/test_packages.py
@@ -13,7 +13,7 @@
         with util.mock_modules('pkg.__init__', 'pkg.module') as mock:
             with util.import_state(meta_path=[mock]):
                 module = import_util.import_('pkg.module')
-                self.assert_('pkg' in sys.modules)
+                self.assertTrue('pkg' in sys.modules)
 
     def test_bad_parent(self):
         with util.mock_modules('pkg.module') as mock: