bpo-30853: IDLE - touch-up configdialog.VarTrace and tests. (python#2936)

Add clear method for tests. Adjust tests to use global instance. Remove unneeded ConfigDialog method.

Author: terryjreedy

Lib/idlelib/configdialog.py

@@ -99,7 +99,6 @@ def create_widgets(self):
  create_page_extensions
  create_action_buttons
  load_configs: Load pages except for extensions.
- remove_var_callbacks
  activate_config_changes: Tell editors to reload.
  """
  self.tab_pages = TabbedPageSet(self,
@@ -133,10 +132,6 @@ def load_configs(self):
  self.load_general_cfg()
  # note: extension page handled separately
 
- def remove_var_callbacks(self):
- "Remove callbacks to prevent memory leaks."
- tracers.detach()
-
  def create_action_buttons(self):
  """Return frame of action buttons for dialog.
 
@@ -1846,6 +1841,11 @@ def __init__(self):
  self.untraced = []
  self.traced = []
 
+ def clear(self):
+ "Clear lists (for tests)."
+ self.untraced.clear()
+ self.traced.clear()
+
  def add(self, var, callback):
  """Add (var, callback) tuple to untraced list.
 

Lib/idlelib/idle_test/test_configdialog.py

@@ -11,7 +11,7 @@
 from idlelib.idle_test.mock_idle import Func
 from tkinter import Tk, IntVar, BooleanVar, DISABLED, NORMAL
 from idlelib import config
-from idlelib.configdialog import ConfigDialog, idleConf, changes, VarTrace
+from idlelib.configdialog import idleConf, changes, tracers
 
 # Tests should not depend on fortuitous user configurations.
 # They must not affect actual user .cfg files.
@@ -35,12 +35,12 @@ def setUpModule():
  idleConf.userCfg = testcfg
  root = Tk()
  # root.withdraw() # Comment out, see issue 30870
- dialog = ConfigDialog(root, 'Test', _utest=True)
+ dialog = configdialog.ConfigDialog(root, 'Test', _utest=True)
 
 def tearDownModule():
  global root, dialog
  idleConf.userCfg = usercfg
- dialog.remove_var_callbacks()
+ tracers.detach()
  del dialog
  root.update_idletasks()
  root.destroy()
@@ -423,14 +423,14 @@ def test_update_help_changes(self):
  d.update_help_changes = Func()
 
 
-class TestVarTrace(unittest.TestCase):
+class VarTraceTest(unittest.TestCase):
 
  def setUp(self):
  changes.clear()
+ tracers.clear()
  self.v1 = IntVar(root)
  self.v2 = BooleanVar(root)
  self.called = 0
- self.tracers = VarTrace()
 
  def tearDown(self):
  del self.v1, self.v2
@@ -442,11 +442,19 @@ def var_changed_boolean(self, *params):
  pass
 
  def test_init(self):
- self.assertEqual(self.tracers.untraced, [])
- self.assertEqual(self.tracers.traced, [])
+ tracers.__init__()
+ self.assertEqual(tracers.untraced, [])
+ self.assertEqual(tracers.traced, [])
+
+ def test_clear(self):
+ tracers.untraced.append(0)
+ tracers.traced.append(1)
+ tracers.clear()
+ self.assertEqual(tracers.untraced, [])
+ self.assertEqual(tracers.traced, [])
 
  def test_add(self):
- tr = self.tracers
+ tr = tracers
  func = Func()
  cb = tr.make_callback = mock.Mock(return_value=func)
 
@@ -469,8 +477,7 @@ def test_add(self):
  del tr.make_callback
 
  def test_make_callback(self):
- tr = self.tracers
- cb = tr.make_callback(self.v1, ('main', 'section', 'option'))
+ cb = tracers.make_callback(self.v1, ('main', 'section', 'option'))
  self.assertTrue(callable(cb))
  self.v1.set(42)
  # Not attached, so set didn't invoke the callback.
@@ -481,7 +488,7 @@ def test_make_callback(self):
  self.assertEqual(changes['main']['section']['option'], '42')
 
  def test_attach_detach(self):
- tr = self.tracers
+ tr = tracers
  v1 = tr.add(self.v1, self.var_changed_increment)
  v2 = tr.add(self.v2, self.var_changed_boolean)
  expected = [(v1, self.var_changed_increment),