Issue #18104: Add idlelib/idle_test/htest.py with a few sample tests to begin
consolidating and improving human-validated tests of Idle. Change other files
as needed to work with htest.  Running the module as __main__ runs all tests.
diff --git a/Lib/idlelib/aboutDialog.py b/Lib/idlelib/aboutDialog.py
index 0734518..05631fa 100644
--- a/Lib/idlelib/aboutDialog.py
+++ b/Lib/idlelib/aboutDialog.py
@@ -12,7 +12,7 @@
     """Modal about dialog for idle
 
     """
-    def __init__(self,parent,title):
+    def __init__(self, parent, title):
         Toplevel.__init__(self, parent)
         self.configure(borderwidth=5)
         self.geometry("+%d+%d" % (parent.winfo_rootx()+30,
@@ -136,10 +136,5 @@
         self.destroy()
 
 if __name__ == '__main__':
-    # test the dialog
-    root = Tk()
-    def run():
-        from idlelib import aboutDialog
-        aboutDialog.AboutDialog(root, 'About')
-    Button(root, text='Dialog', command=run).pack()
-    root.mainloop()
+    from idlelib.idle_test.htest import run
+    run(AboutDialog)