Start writing main unittests to grapple with its complexity.
Fix dependency injection in main to make main unittests pass.
Whitespace change - use newlines immediately after '(' in calls.
Undo a configurability-anticipating API change; it's early complexity.
Factor out common code for running main tests for one child.
Add a unittest to expose the default argparse flexibility of option locations, which is a bug for this UI.
Add OrderedStringIO and fake_select for test determinism; fix interspersed parsing bug.'
Put top-level test code before utility code.