test: adapt Tkinter tests for Tk 8.6.12

Backport the relevant behavior changes from bpo-45436 (4fe454c), bpo-41306 (aecf036), and the bpo-45979 correction (dbbe4d2).

Retain the older Tk expectations. On Tk 8.6.11+, explicitly test empty Menu.type and ttk compound values while still rejecting invalid enum values. On Tk 8.6.10+, expect Scale.from to retain its fractional value.

Validated test_tk and test_ttk_guionly with Python 3.6 and Tcl/Tk 8.6.12 on openSUSE Leap 15.6, including the affected widget classes with wantobjects disabled.

Author: mcepl

Lib/tkinter/test/test_tkinter/test_widgets.py

@@ -864,7 +864,9 @@ def test_digits(self):
 
     def test_from(self):
         widget = self.create()
-        self.checkFloatParam(widget, 'from', 100, 14.9, 15.1, conv=float_round)
+        # bpo-41306: Tk 8.6.10 no longer rounds the 'from' option.
+        conv = float if get_tk_patchlevel() >= (8, 6, 10) else float_round
+        self.checkFloatParam(widget, 'from', 100, 14.9, 15.1, conv=conv)
 
     def test_label(self):
         widget = self.create()
@@ -1165,8 +1167,10 @@ def test_title(self):
 
     def test_type(self):
         widget = self.create()
+        # bpo-45436: Tk 8.6.11 accepts an empty menu type.
         self.checkEnumParam(widget, 'type',
-                'normal', 'tearoff', 'menubar')
+                'normal', 'tearoff', 'menubar',
+                allow_empty=get_tk_patchlevel() >= (8, 6, 11))
 
     def test_entryconfigure(self):
         m1 = self.create()

Lib/tkinter/test/test_ttk/test_widgets.py

@@ -171,9 +171,11 @@ def checkImageParam(self, widget, name):
 
     def test_compound(self):
         widget = self.create()
+        # bpo-45436: Tk 8.6.11 accepts an empty compound option.
         self.checkEnumParam(widget, 'compound',
                 'none', 'text', 'image', 'center',
-                'top', 'bottom', 'left', 'right')
+                'top', 'bottom', 'left', 'right',
+                allow_empty=get_tk_patchlevel() >= (8, 6, 11))
 
     def test_state(self):
         widget = self.create()

Lib/tkinter/test/widget_tests.py

@@ -144,18 +144,22 @@ def command(*args):
         self.assertTrue(widget[name])
         self.checkParams(widget, name, '')
 
-    def checkEnumParam(self, widget, name, *values, errmsg=None, **kwargs):
+    def checkEnumParam(self, widget, name, *values, errmsg=None,
+                       allow_empty=False, **kwargs):
         self.checkParams(widget, name, *values, **kwargs)
         if errmsg is None:
             errmsg2 = ' %s "{}": must be %s%s or %s' % (
                     name,
                     ', '.join(values[:-1]),
                     ',' if len(values) > 2 else '',
                     values[-1])
-            self.checkInvalidParam(widget, name, '',
-                                   errmsg='ambiguous' + errmsg2)
+            if not allow_empty:
+                self.checkInvalidParam(widget, name, '',
+                                       errmsg='ambiguous' + errmsg2)
             errmsg = 'bad' + errmsg2
         self.checkInvalidParam(widget, name, 'spam', errmsg=errmsg)
+        if allow_empty:
+            self.checkParam(widget, name, '', **kwargs)
 
     def checkPixelsParam(self, widget, name, *values,
                          conv=None, keep_orig=True, **kwargs):