bpo-33839: refactor IDLE's tooltips & calltips, add docstrings and tests (GH-7683)

* make CallTip and ToolTip sub-classes of a common abstract base class
* remove ListboxToolTip (unused and ugly)
* greatly increase test coverage
* tested on Windows, Linux and macOS

Lib/idlelib/idle_test/test_tooltip.py

@@ -0,0 +1,146 @@
+from idlelib.tooltip import TooltipBase, Hovertip
+from test.support import requires
+requires('gui')
+
+from functools import wraps
+import time
+from tkinter import Button, Tk, Toplevel
+import unittest
+
+
+def setUpModule():
+    global root
+    root = Tk()
+
+def root_update():
+    global root
+    root.update()
+
+def tearDownModule():
+    global root
+    root.update_idletasks()
+    root.destroy()
+    del root
+
+def add_call_counting(func):
+    @wraps(func)
+    def wrapped_func(*args, **kwargs):
+        wrapped_func.call_args_list.append((args, kwargs))
+        return func(*args, **kwargs)
+    wrapped_func.call_args_list = []
+    return wrapped_func
+
+
+def _make_top_and_button(testobj):
+    global root
+    top = Toplevel(root)
+    testobj.addCleanup(top.destroy)
+    top.title("Test tooltip")
+    button = Button(top, text='ToolTip test button')
+    button.pack()
+    testobj.addCleanup(button.destroy)
+    top.lift()
+    return top, button
+
+
+class ToolTipBaseTest(unittest.TestCase):
+    def setUp(self):
+        self.top, self.button = _make_top_and_button(self)
+
+    def test_base_class_is_unusable(self):
+        global root
+        top = Toplevel(root)
+        self.addCleanup(top.destroy)
+
+        button = Button(top, text='ToolTip test button')
+        button.pack()
+        self.addCleanup(button.destroy)
+
+        with self.assertRaises(NotImplementedError):
+            tooltip = TooltipBase(button)
+            tooltip.showtip()
+
+
+class HovertipTest(unittest.TestCase):
+    def setUp(self):
+        self.top, self.button = _make_top_and_button(self)
+
+    def test_showtip(self):
+        tooltip = Hovertip(self.button, 'ToolTip text')
+        self.addCleanup(tooltip.hidetip)
+        self.assertFalse(tooltip.tipwindow and tooltip.tipwindow.winfo_viewable())
+        tooltip.showtip()
+        self.assertTrue(tooltip.tipwindow and tooltip.tipwindow.winfo_viewable())
+
+    def test_showtip_twice(self):
+        tooltip = Hovertip(self.button, 'ToolTip text')
+        self.addCleanup(tooltip.hidetip)
+        self.assertFalse(tooltip.tipwindow and tooltip.tipwindow.winfo_viewable())
+        tooltip.showtip()
+        self.assertTrue(tooltip.tipwindow and tooltip.tipwindow.winfo_viewable())
+        orig_tipwindow = tooltip.tipwindow
+        tooltip.showtip()
+        self.assertTrue(tooltip.tipwindow and tooltip.tipwindow.winfo_viewable())
+        self.assertIs(tooltip.tipwindow, orig_tipwindow)
+
+    def test_hidetip(self):
+        tooltip = Hovertip(self.button, 'ToolTip text')
+        self.addCleanup(tooltip.hidetip)
+        tooltip.showtip()
+        tooltip.hidetip()
+        self.assertFalse(tooltip.tipwindow and tooltip.tipwindow.winfo_viewable())
+
+    def test_showtip_on_mouse_enter_no_delay(self):
+        tooltip = Hovertip(self.button, 'ToolTip text', hover_delay=None)
+        self.addCleanup(tooltip.hidetip)
+        tooltip.showtip = add_call_counting(tooltip.showtip)
+        root_update()
+        self.assertFalse(tooltip.tipwindow and tooltip.tipwindow.winfo_viewable())
+        self.button.event_generate('<Enter>', x=0, y=0)
+        root_update()
+        self.assertTrue(tooltip.tipwindow and tooltip.tipwindow.winfo_viewable())
+        self.assertGreater(len(tooltip.showtip.call_args_list), 0)
+
+    def test_showtip_on_mouse_enter_hover_delay(self):
+        tooltip = Hovertip(self.button, 'ToolTip text', hover_delay=50)
+        self.addCleanup(tooltip.hidetip)
+        tooltip.showtip = add_call_counting(tooltip.showtip)
+        root_update()
+        self.assertFalse(tooltip.tipwindow and tooltip.tipwindow.winfo_viewable())
+        self.button.event_generate('<Enter>', x=0, y=0)
+        root_update()
+        self.assertFalse(tooltip.tipwindow and tooltip.tipwindow.winfo_viewable())
+        time.sleep(0.1)
+        root_update()
+        self.assertTrue(tooltip.tipwindow and tooltip.tipwindow.winfo_viewable())
+        self.assertGreater(len(tooltip.showtip.call_args_list), 0)
+
+    def test_hidetip_on_mouse_leave(self):
+        tooltip = Hovertip(self.button, 'ToolTip text', hover_delay=None)
+        self.addCleanup(tooltip.hidetip)
+        tooltip.showtip = add_call_counting(tooltip.showtip)
+        root_update()
+        self.button.event_generate('<Enter>', x=0, y=0)
+        root_update()
+        self.button.event_generate('<Leave>', x=0, y=0)
+        root_update()
+        self.assertFalse(tooltip.tipwindow and tooltip.tipwindow.winfo_viewable())
+        self.assertGreater(len(tooltip.showtip.call_args_list), 0)
+
+    def test_dont_show_on_mouse_leave_before_delay(self):
+        tooltip = Hovertip(self.button, 'ToolTip text', hover_delay=50)
+        self.addCleanup(tooltip.hidetip)
+        tooltip.showtip = add_call_counting(tooltip.showtip)
+        root_update()
+        self.button.event_generate('<Enter>', x=0, y=0)
+        root_update()
+        self.button.event_generate('<Leave>', x=0, y=0)
+        root_update()
+        time.sleep(0.1)
+        root_update()
+        self.assertFalse(tooltip.tipwindow and tooltip.tipwindow.winfo_viewable())
+        self.assertEqual(tooltip.showtip.call_args_list, [])
+
+
+if __name__ == '__main__':
+    unittest.main(verbosity=2)