bpo-42142: Try to fix timeouts in ttk tests (GH-23474)

Instead of using wait_visibility() which waits event <VisibilityNotify> in dead loop
use update() which should proceed all queued events.
(cherry picked from commit 6cc2c419f6)

Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>

Lib/tkinter/test/test_ttk/test_extensions.py

@@ -114,7 +114,6 @@ class LabeledScaleTest(AbstractTkTest, unittest.TestCase):
     def test_horizontal_range(self):
         lscale = ttk.LabeledScale(self.root, from_=0, to=10)
         lscale.pack()
-        lscale.wait_visibility()
         lscale.update()
 
         linfo_1 = lscale.label.place_info()
@@ -144,7 +143,6 @@ class LabeledScaleTest(AbstractTkTest, unittest.TestCase):
     def test_variable_change(self):
         x = ttk.LabeledScale(self.root)
         x.pack()
-        x.wait_visibility()
         x.update()
 
         curr_xcoord = x.scale.coords()[0]
@@ -187,7 +185,6 @@ class LabeledScaleTest(AbstractTkTest, unittest.TestCase):
     def test_resize(self):
         x = ttk.LabeledScale(self.root)
         x.pack(expand=True, fill='both')
-        x.wait_visibility()
         x.update()
 
         width, height = x.master.winfo_width(), x.master.winfo_height()
@@ -268,7 +265,6 @@ class OptionMenuTest(AbstractTkTest, unittest.TestCase):
 
         # check that variable is updated correctly
         optmenu.pack()
-        optmenu.wait_visibility()
         optmenu['menu'].invoke(0)
         self.assertEqual(optmenu._variable.get(), items[0])
 
@@ -299,9 +295,7 @@ class OptionMenuTest(AbstractTkTest, unittest.TestCase):
         textvar2 = tkinter.StringVar(self.root)
         optmenu2 = ttk.OptionMenu(self.root, textvar2, default, *items)
         optmenu.pack()
-        optmenu.wait_visibility()
         optmenu2.pack()
-        optmenu2.wait_visibility()
         optmenu['menu'].invoke(1)
         optmenu2['menu'].invoke(2)
         optmenu_stringvar_name = optmenu['menu'].entrycget(0, 'variable')

Lib/tkinter/test/test_ttk/test_widgets.py

@@ -60,11 +60,10 @@ class WidgetTest(AbstractTkTest, unittest.TestCase):
         super().setUp()
         self.widget = ttk.Button(self.root, width=0, text="Text")
         self.widget.pack()
-        self.widget.wait_visibility()
 
 
     def test_identify(self):
-        self.widget.update_idletasks()
+        self.widget.update()
         self.assertEqual(self.widget.identify(
             int(self.widget.winfo_width() / 2),
             int(self.widget.winfo_height() / 2)
@@ -326,8 +325,7 @@ class EntryTest(AbstractWidgetTest, unittest.TestCase):
 
     def test_identify(self):
         self.entry.pack()
-        self.entry.wait_visibility()
-        self.entry.update_idletasks()
+        self.entry.update()
 
         # bpo-27313: macOS Cocoa widget differs from X, allow either
         if sys.platform == 'darwin':
@@ -449,7 +447,7 @@ class ComboboxTest(EntryTest, unittest.TestCase):
         self.combo.bind('<<ComboboxSelected>>',
             lambda evt: success.append(True))
         self.combo.pack()
-        self.combo.wait_visibility()
+        self.combo.update()
 
         height = self.combo.winfo_height()
         self._show_drop_down_listbox()
@@ -465,7 +463,7 @@ class ComboboxTest(EntryTest, unittest.TestCase):
 
         self.combo['postcommand'] = lambda: success.append(True)
         self.combo.pack()
-        self.combo.wait_visibility()
+        self.combo.update()
 
         self._show_drop_down_listbox()
         self.assertTrue(success)
@@ -665,7 +663,6 @@ class PanedWindowTest(AbstractWidgetTest, unittest.TestCase):
         self.assertRaises(tkinter.TclError, self.paned.sashpos, 1)
 
         self.paned.pack(expand=True, fill='both')
-        self.paned.wait_visibility()
 
         curr_pos = self.paned.sashpos(0)
         self.paned.sashpos(0, 1000)
@@ -933,7 +930,7 @@ class NotebookTest(AbstractWidgetTest, unittest.TestCase):
         self.nb.add(self.child1, text='a')
 
         self.nb.pack()
-        self.nb.wait_visibility()
+        self.nb.update()
         if sys.platform == 'darwin':
             tb_idx = "@20,5"
         else:
@@ -1041,7 +1038,7 @@ class NotebookTest(AbstractWidgetTest, unittest.TestCase):
 
     def test_select(self):
         self.nb.pack()
-        self.nb.wait_visibility()
+        self.nb.update()
 
         success = []
         tab_changed = []
@@ -1084,7 +1081,7 @@ class NotebookTest(AbstractWidgetTest, unittest.TestCase):
 
     def test_traversal(self):
         self.nb.pack()
-        self.nb.wait_visibility()
+        self.nb.update()
 
         self.nb.select(0)
 
@@ -1342,7 +1339,6 @@ class TreeviewTest(AbstractWidgetTest, unittest.TestCase):
     def test_bbox(self):
         self.tv.pack()
         self.assertEqual(self.tv.bbox(''), '')
-        self.tv.wait_visibility()
         self.tv.update()
 
         item_id = self.tv.insert('', 'end')
@@ -1536,7 +1532,6 @@ class TreeviewTest(AbstractWidgetTest, unittest.TestCase):
         success = [] # no success for now
 
         self.tv.pack()
-        self.tv.wait_visibility()
         self.tv.heading('#0', command=lambda: success.append(True))
         self.tv.column('#0', width=100)
         self.tv.update()
@@ -1784,7 +1779,6 @@ class TreeviewTest(AbstractWidgetTest, unittest.TestCase):
             lambda evt: events.append(2))
 
         self.tv.pack()
-        self.tv.wait_visibility()
         self.tv.update()
 
         pos_y = set()