Issue *24750: Switch all scrollbars in IDLE to ttk versions.

Where needed, add minimal tests to cover changes.

Lib/idlelib/idle_test/test_debugger.py

@@ -0,0 +1,29 @@
+''' Test idlelib.debugger.
+
+Coverage: 19%
+'''
+from idlelib import debugger
+from test.support import requires
+requires('gui')
+import unittest
+from tkinter import Tk
+
+
+class NameSpaceTest(unittest.TestCase):
+
+    @classmethod
+    def setUpClass(cls):
+        cls.root = Tk()
+        cls.root.withdraw()
+
+    @classmethod
+    def tearDownClass(cls):
+        cls.root.destroy()
+        del cls.root
+
+    def test_init(self):
+        debugger.NamespaceViewer(self.root, 'Test')
+
+
+if __name__ == '__main__':
+    unittest.main(verbosity=2)