bpo-30993: IDLE - Improve configdialog font page and tests. (#2818)

* Document causal event pathways in docstring.
* Simplify some attribute names.
* Rename test_bold_toggle_set_samples to make test_font_set fail.
* Fix test_font_set so not order dependent.
* Fix renamed test_indent_scale so it tests the widget.

1 files changed, 51 insertions, 48 deletions

diff --git a/Lib/idlelib/configdialog.py b/Lib/idlelib/configdialog.py
index c1db768..d51eca6 100644
--- a/Lib/idlelib/configdialog.py
+++ b/Lib/idlelib/configdialog.py
@@ -153,70 +153,73 @@ class ConfigDialog(Toplevel):
     def create_page_font_tab(self):
         """Return frame of widgets for Font/Tabs tab.
 
-        Enable users to provisionally change font face, size, or
+        Fonts: Enable users to provisionally change font face, size, or
         boldness and to see the consequence of proposed choices.  Each
         action set 3 options in changes structuree and changes the
         corresponding aspect of the font sample on this page and
         highlight sample on highlight page.
 
-        Enable users to change spaces entered for indent tabs.
+        Fontlist: mouse button 1 click or up or down key invoke
+        on_fontlist_select(), which sets Var font_name and calls
+        set_samples.
 
-        Tk Variables:
-            font_name: Font face.
-            font_size: Font size.
-            font_bold: Select font bold or not.
-                Note: these 3 share var_changed_font callback.
-            space_num: Indentation width.
+        Sizelist: clicking the menubutton opens the dropdown menu. A
+        mouse button 1 click or return key invokes an internal command
+        which sets Var font_size and calls set_samples.
 
-        Data Attribute:
-            edit_font: Font with default font name, size, and weight.
+        Bold_toggle, clicking the box toggles font_bold and calls
+        set_samples.
 
-        Methods:
-            load_font_cfg: Set vars and fontlist.
-            on_fontlist_select: Bound to fontlist button release
-                or key release.
-            set_samples: Notify both samples of any font change.
-            load_tab_cfg: Get current.
+        Setting any of the font vars invokes var_changed_font, which
+        adds all 3 font options to changes.  Set_samples applies a new
+        font constructed from the font vars to font_sample and
+        highlight_sample on the hightlight page.
+
+        Tabs: Enable users to change spaces entered for indent tabs.
+        Changing indent_scale value with the mouse sets Var space_num,
+        which invokes var_changed_space_num, which adds an entry to
+        changes.
+
+        Load_font_cfg and load_tab_cfg initialize vars and widgets from
+        idleConf entries.
 
         Widget Structure:  (*) widgets bound to self
-            frame
+            frame (of tab_pages)
                 frame_font: LabelFrame
                     frame_font_name: Frame
                         font_name_title: Label
-                        (*)fontlist: ListBox
+                        (*)fontlist: ListBox - font_name
                         scroll_font: Scrollbar
                     frame_font_param: Frame
                         font_size_title: Label
-                        (*)opt_menu_font_size: DynOptionMenu - font_size
+                        (*)sizelist: DynOptionMenu - font_size
                         (*)bold_toggle: Checkbutton - font_bold
                     frame_font_sample: Frame
                         (*)font_sample: Label
                 frame_indent: LabelFrame
-                    frame_indent_size: Frame
-                        indent_size_title: Label
-                        (*)scale_indent_size: Scale - space_num
+                        indent_title: Label
+                        (*)indent_scale: Scale - space_num
         """
         parent = self.parent
         self.font_name = StringVar(parent)
         self.font_size = StringVar(parent)
         self.font_bold = BooleanVar(parent)
         self.space_num = IntVar(parent)
-        self.edit_font = tkFont.Font(parent, ('courier', 10, 'normal'))
 
-        # Create widgets.
+        # Create widgets:
         # body and body section frames.
         frame = self.tab_pages.pages['Fonts/Tabs'].frame
         frame_font = LabelFrame(
                 frame, borderwidth=2, relief=GROOVE, text=' Base Editor Font ')
         frame_indent = LabelFrame(
                 frame, borderwidth=2, relief=GROOVE, text=' Indentation Width ')
-        # frame_font
+        # frame_font.
         frame_font_name = Frame(frame_font)
         frame_font_param = Frame(frame_font)
         font_name_title = Label(
                 frame_font_name, justify=LEFT, text='Font Face :')
-        self.fontlist = Listbox(
-                frame_font_name, height=5, takefocus=FALSE, exportselection=FALSE)
+        self.fontlist = Listbox(frame_font_name, height=5,
+                                takefocus=FALSE, exportselection=FALSE)
         self.fontlist.bind('<ButtonRelease-1>', self.on_fontlist_select)
         self.fontlist.bind('<KeyRelease-Up>', self.on_fontlist_select)
         self.fontlist.bind('<KeyRelease-Down>', self.on_fontlist_select)
@@ -224,43 +227,43 @@ class ConfigDialog(Toplevel):
         scroll_font.config(command=self.fontlist.yview)
         self.fontlist.config(yscrollcommand=scroll_font.set)
         font_size_title = Label(frame_font_param, text='Size :')
-        self.opt_menu_font_size = DynOptionMenu(
-                frame_font_param, self.font_size, None, command=self.set_samples)
+        self.sizelist = DynOptionMenu(frame_font_param, self.font_size,
+                                      None, command=self.set_samples)
         self.bold_toggle = Checkbutton(
                 frame_font_param, variable=self.font_bold, onvalue=1,
                 offvalue=0, text='Bold', command=self.set_samples)
         frame_font_sample = Frame(frame_font, relief=SOLID, borderwidth=1)
+        temp_font = tkFont.Font(parent, ('courier', 10, 'normal'))
         self.font_sample = Label(
-                frame_font_sample, justify=LEFT, font=self.edit_font,
+                frame_font_sample, justify=LEFT, font=temp_font,
                 text='AaBbCcDdEe\nFfGgHhIiJjK\n1234567890\n#:+=(){}[]')
-        # frame_indent
-        frame_indent_size = Frame(frame_indent)
-        indent_size_title = Label(
-                frame_indent_size, justify=LEFT,
+        # frame_indent.
+        indent_title = Label(
+                frame_indent, justify=LEFT,
                 text='Python Standard: 4 Spaces!')
-        self.scale_indent_size = Scale(
-                frame_indent_size, variable=self.space_num,
+        self.indent_scale = Scale(
+                frame_indent, variable=self.space_num,
                 orient='horizontal', tickinterval=2, from_=2, to=16)
 
-        # Pack widgets.
-        # body
+        # Pack widgets:
+        # body.
         frame_font.pack(side=LEFT, padx=5, pady=5, expand=TRUE, fill=BOTH)
         frame_indent.pack(side=LEFT, padx=5, pady=5, fill=Y)
-        # frame_font
+        # frame_font.
         frame_font_name.pack(side=TOP, padx=5, pady=5, fill=X)
         frame_font_param.pack(side=TOP, padx=5, pady=5, fill=X)
         font_name_title.pack(side=TOP, anchor=W)
         self.fontlist.pack(side=LEFT, expand=TRUE, fill=X)
         scroll_font.pack(side=LEFT, fill=Y)
         font_size_title.pack(side=LEFT, anchor=W)
-        self.opt_menu_font_size.pack(side=LEFT, anchor=W)
+        self.sizelist.pack(side=LEFT, anchor=W)
         self.bold_toggle.pack(side=LEFT, anchor=W, padx=20)
         frame_font_sample.pack(side=TOP, padx=5, pady=5, expand=TRUE, fill=BOTH)
         self.font_sample.pack(expand=TRUE, fill=BOTH)
-        # frame_indent
-        frame_indent_size.pack(side=TOP, fill=X)
-        indent_size_title.pack(side=TOP, anchor=W, padx=5)
-        self.scale_indent_size.pack(side=TOP, padx=5, fill=X)
+        # frame_indent.
+        frame_indent.pack(side=TOP, fill=X)
+        indent_title.pack(side=TOP, anchor=W, padx=5)
+        self.indent_scale.pack(side=TOP, padx=5, fill=X)
 
         return frame
 
@@ -1410,7 +1413,7 @@ class ConfigDialog(Toplevel):
         Attributes updated:
             fontlist: Populate with fonts from tkinter.font.
             font_name: Set to current font.
-            opt_menu_font_size: Populate valid options tuple and set
+            sizelist: Populate valid options tuple and set
                 to current size.
             font_bold: Set to current font weight.
 
@@ -1437,9 +1440,9 @@ class ConfigDialog(Toplevel):
         except ValueError:
             pass
         # Set font size dropdown.
-        self.opt_menu_font_size.SetMenu(('7', '8', '9', '10', '11', '12', '13',
-                                      '14', '16', '18', '20', '22',
-                                      '25', '29', '34', '40'), font_size )
+        self.sizelist.SetMenu(('7', '8', '9', '10', '11', '12', '13', '14',
+                               '16', '18', '20', '22', '25', '29', '34', '40'),
+                              font_size)
         # Set font weight.
         self.font_bold.set(font_bold)
         # Set font sample.