I have accepted what I think is the core idea  -- testing functional pathways starting with user actions instead or in addition to pure unit tests.  For instance, test_configdialog.GeneralTest (newly revised in PR 2612) invokes buttons and inserts entries.  These simulated user actions change  Variable values; the trace callback is then called to add an option to the changes data structure.  The test is that the right addition was made.  I will not bother to test the callback separately as a unit.

Test speed is very important to me as I rerun a module's tests constantly when editing a module or test_module.  I try to efficiently cover the code, including taking branches both ways, without heaps of redundancy.

The search box tests use tk introspecton, but I didn't like it as it.  For me, it made the tests less clear. I would rather trade space for speed and clarity by keeping named references to all python objects needed for tests.

So for the moment, I prefer my implementation of the core idea.