Missing "requires('gui')" causes Tk() to fail when no gui.
This caused CI Hypothesis test to fail, but I did not understand
the its error message. Then buildbots failed.
IdbTest failed on draft Bdb replacement because so different.
Simplified version works on old and new.
Add docstrings to the debugger module. Fix two bugs: initialize Idb.botframe (should be in Bdb); In Idb.in_rpc_code, check whether prev_frame is None before trying to use it. Make other code changes.
Expand test_debugger coverage from 19% to 66%.
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Co-authored-by: Terry Jan Reedy <tjreedy@udel.edu>
Create a template for minimally testing a tkinter-using module by importing it and instantiating its class(es). Add a test file for all non-startup IDLE modules. Edit existing files and update coverage. This is part 1 of 3, covering the 21 autocomplete to help modules and touching 33 idlelib files.
Terry Jan Reedy
Anthony Shaw