Add regression test for boolean input with a default (#779)

[arimu1]

Summary

Addresses #779.

Issue #779 reported that a boolean input with default: false was incorrectly treated as a required CLI argument:

$ cwltool t.cwl
t.cwl: error: the following arguments are required: --a_false

…while default: true worked fine — an argparse-generation asymmetry.

Status: already fixed, never locked down

This was fixed in 48e8afd (Aug 2019), when the required computation in add_argument became:

required = default is None and input_required

Since a boolean with default: false has default=False (not None), it is correctly optional today. I confirmed current main runs the issue's repro without error. However, the behavior was never covered by a test and the issue is still open.

Change

Adds a parametrized regression test in tests/test_toolargparse.py (plus two small fixtures under tests/wf/) covering both default: false and default: true. It builds the parser via generate_parser(..., input_required=True) — mirroring the default CLI behavior — and asserts that parsing with no arguments succeeds and falls back to the declared default, rather than erroring as required.

I verified the test genuinely guards the bug: against the pre-2019 logic it fails on the default: false case with the exact error from the issue, while the default: true case still passes — matching the original report.

$ python -m pytest tests/test_toolargparse.py -q
19 passed

black, flake8, and isort are clean on the changed files. Once this lands, #779 can be closed.

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This change was produced with the assistance of Claude Code (model: Claude Opus). The analysis and test were reviewed by a human before submission.