[00/11] patchtest: improve testing coverage

Make changes to the patchtest script, helper modules, test suites, and selftest
files to address various shortcomings with the current version, including:

- Re-enable the previously included mergeability tests, which have been broken
  since prior to the 2023 Yocto RFQ
- Improve series testing by fixing signal handling and return code logic for the
  '--directory' flag, and by making it possible for patchtest to report the
  shortlog for failing commits when testing series as single files
- Make branch checking for merge tests more robust but retain flexibility for
  the selftest suite, and so that users can test series against branches other
  than the target one
- Add new tests for malformed lines and whitespace in the TestPatch module
- Refactors across the entire suite to remove dead code, simplify logic, and
  update selftest files
- Expand the selftest file suite for all of the new cases added, bringing us
  from 38 to 51 selftests.

Before: 

|============================================================================
|Testsuite summary for patchtest
|============================================================================
|# TOTAL: 38
|# XPASS: 18
|# XFAIL: 18
|# XSKIP: 2
|# PASS: 0
|# FAIL: 0
|# SKIP: 0
|# ERROR: 0
|============================================================================

After:

|============================================================================
|Testsuite summary for patchtest
|============================================================================
|# TOTAL: 51
|# XPASS: 25
|# XFAIL: 26
|# XSKIP: 0
|# PASS: 0
|# FAIL: 0
|# SKIP: 0
|# ERROR: 0
|============================================================================

As always, there's lots of room for patchtest to grow further (I'd still very
much like to convert it to a standalone Python tool one day). However, this is
already a sizeable rework, and it should bring immediate benefit to anyone using
it. I've made a point to label each individual patch appropriately, but for
emphasis this work has been done in tandem with the Claude AI, specifically
Sonnet 4.6 and 4.7. 

Given the skepticism that many of us have towards AI tooling, I made a point to
do a review of the changes Claude had made myself before performing the final
squash and rebase. This did reveal some bloat that I've since removed, but for
the most part it made functional and useful changes. The selftest suite was
routinely triggered locally to ensure it didn't cause any bizarre regressions,
and new selftest files were added immediately for new test cases (or, in the
case of the mergeability tests, refactored so that they were no longer labeled
as skips). I've also made a point to pull patch series at random from the
mailing list and test directly.

Parts of this series (such as the '--directory' usage improvements) were written
to address the needs of folks at Smile. Others address one or more outstanding
bugs in Bugzilla, which I haven't consistently labeled as such (but I'll close
them when this gets merged). The next priority will be to improve the actual
deployment of the Patchtest service on the Yocto Project infrastructure.

Trevor Gamblin (11):
  patchtest: check for meta-selftest, cleanup script
  patchtest: test series mergeability
  patchtest: tests: cleanup test suites
  patchtest: correctly abort --directory test
  patchtest: fix branch applicability reporting
  patchtest: test_patch: improve patch-specific tests
  patchtest: test_mbox: skip cover letters
  patchtest: mbox.py: improve 'From' line matching
  patchtest: selftest: stop if patchtest fails
  patchtest: selftest: rework test files
  patchtest: selftest: extend test file suite

 meta/lib/patchtest/mbox.py                    |  56 ++---
 meta/lib/patchtest/patchtest_parser.py        |   2 +-
 meta/lib/patchtest/patchtest_patterns.py      |   5 +
 meta/lib/patchtest/repo.py                    |  48 +++++
 ...x.pretest_series_applies_on_branch.1.pass} |  22 +-
 ...x.pretest_series_applies_on_branch.2.fail} |   0
 .../TestMbox.test_bugzilla_entry_format.fail  |   5 +-
 .../TestMbox.test_bugzilla_entry_format.pass  |   5 +-
 ...TestMbox.test_commit_message_presence.fail |   5 +-
 ...TestMbox.test_commit_message_presence.pass |   5 +-
 ...tMbox.test_commit_message_user_tags.1.pass |   5 +-
 ...tMbox.test_commit_message_user_tags.2.pass |   5 +-
 ...estMbox.test_commit_message_user_tags.fail |   5 +-
 .../files/TestMbox.test_mbox_format.pass      |   5 +-
 .../files/TestMbox.test_non_auh_upgrade.fail  |  25 +++
 .../files/TestMbox.test_non_auh_upgrade.pass  |  25 +++
 .../files/TestMbox.test_shortlog_format.fail  |   5 +-
 .../files/TestMbox.test_shortlog_format.pass  |   5 +-
 .../files/TestMbox.test_shortlog_length.fail  |   5 +-
 .../files/TestMbox.test_shortlog_length.pass  |   5 +-
 ...estMbox.test_signed_off_by_presence.1.fail |   5 +-
 ...estMbox.test_signed_off_by_presence.2.fail |   5 +-
 .../TestMbox.test_signed_off_by_presence.pass |   5 +-
 .../TestMbox.test_target_mailing_list.1.fail  |  26 +++
 .../TestMbox.test_target_mailing_list.2.fail  |  24 +++
 .../TestMbox.test_target_mailing_list.pass    |  25 +++
 .../TestMetadata.test_max_line_length.fail    |  26 +++
 .../TestMetadata.test_max_line_length.pass    |  25 +++
 .../files/TestPatch.test_cve_tag_format.fail  |   5 +-
 .../files/TestPatch.test_cve_tag_format.pass  |   5 +-
 ...estPatch.test_patch_malformed_context.fail |  38 ++++
 ...estPatch.test_patch_malformed_context.pass |  38 ++++
 ...tPatch.test_patch_trailing_whitespace.fail |  38 ++++
 ...tPatch.test_patch_trailing_whitespace.pass |  38 ++++
 ...TestPatch.test_signed_off_by_presence.fail |   5 +-
 ...TestPatch.test_signed_off_by_presence.pass |   5 +-
 ....test_upstream_status_presence_format.fail |  61 ++++++
 ....test_upstream_status_presence_format.pass |  62 ++++++
 meta/lib/patchtest/selftest/selftest          |  25 ++-
 meta/lib/patchtest/tests/base.py              | 117 ++++------
 meta/lib/patchtest/tests/test_mbox.py         |  56 +++--
 meta/lib/patchtest/tests/test_metadata.py     | 112 +++++-----
 meta/lib/patchtest/tests/test_patch.py        | 113 ++++++++--
 .../lib/patchtest/tests/test_python_pylint.py |   8 +-
 scripts/patchtest                             | 200 +++++++++---------
 45 files changed, 904 insertions(+), 406 deletions(-)
 rename meta/lib/patchtest/selftest/files/{TestMbox.test_series_merge_on_head.1.skip => TestMbox.pretest_series_applies_on_branch.1.pass} (66%)
 rename meta/lib/patchtest/selftest/files/{TestMbox.test_series_merge_on_head.2.skip => TestMbox.pretest_series_applies_on_branch.2.fail} (100%)
 create mode 100644 meta/lib/patchtest/selftest/files/TestMbox.test_non_auh_upgrade.fail
 create mode 100644 meta/lib/patchtest/selftest/files/TestMbox.test_non_auh_upgrade.pass
 create mode 100644 meta/lib/patchtest/selftest/files/TestMbox.test_target_mailing_list.1.fail
 create mode 100644 meta/lib/patchtest/selftest/files/TestMbox.test_target_mailing_list.2.fail
 create mode 100644 meta/lib/patchtest/selftest/files/TestMbox.test_target_mailing_list.pass
 create mode 100644 meta/lib/patchtest/selftest/files/TestMetadata.test_max_line_length.fail
 create mode 100644 meta/lib/patchtest/selftest/files/TestMetadata.test_max_line_length.pass
 create mode 100644 meta/lib/patchtest/selftest/files/TestPatch.test_patch_malformed_context.fail
 create mode 100644 meta/lib/patchtest/selftest/files/TestPatch.test_patch_malformed_context.pass
 create mode 100644 meta/lib/patchtest/selftest/files/TestPatch.test_patch_trailing_whitespace.fail
 create mode 100644 meta/lib/patchtest/selftest/files/TestPatch.test_patch_trailing_whitespace.pass
 create mode 100644 meta/lib/patchtest/selftest/files/TestPatch.test_upstream_status_presence_format.fail
 create mode 100644 meta/lib/patchtest/selftest/files/TestPatch.test_upstream_status_presence_format.pass