Yet more test_logging coverage improvements.
diff --git a/Lib/test/test_logging.py b/Lib/test/test_logging.py
index cad0ad7..813e62a 100644
--- a/Lib/test/test_logging.py
+++ b/Lib/test/test_logging.py
@@ -2047,6 +2047,27 @@
             # Original logger output is empty.
             self.assert_log_lines([])
 
+    def test_baseconfig(self):
+        d = {
+            'atuple': (1, 2, 3),
+            'alist': ['a', 'b', 'c'],
+            'adict': {'d': 'e', 'f': 3 },
+            'nest1': ('g', ('h', 'i'), 'j'),
+            'nest2': ['k', ['l', 'm'], 'n'],
+            'nest3': ['o', 'cfg://alist', 'p'],
+        }
+        bc = logging.config.BaseConfigurator(d)
+        self.assertEqual(bc.convert('cfg://atuple[1]'), 2)
+        self.assertEqual(bc.convert('cfg://alist[1]'), 'b')
+        self.assertEqual(bc.convert('cfg://nest1[1][0]'), 'h')
+        self.assertEqual(bc.convert('cfg://nest2[1][1]'), 'm')
+        self.assertEqual(bc.convert('cfg://adict.d'), 'e')
+        self.assertEqual(bc.convert('cfg://adict[f]'), 3)
+        v = bc.convert('cfg://nest3')
+        self.assertEqual(v.pop(1), ['a', 'b', 'c'])
+        self.assertRaises(KeyError, bc.convert, 'cfg://nosuch')
+        self.assertRaises(ValueError, bc.convert, 'cfg://!')
+        self.assertRaises(KeyError, bc.convert, 'cfg://adict[2]')
 
 class ManagerTest(BaseTest):
     def test_manager_loggerclass(self):