[PATCH 10/13] iotests/linters: Add entry point for linting via Python CI

[John Snow]

We need at least a tiny little shim here to join test file discovery
with test invocation. This logic could conceivably be hosted somewhere
in python/, but I felt it was strictly the least-rude thing to keep the
test logic here in iotests/, even if this small function isn't itself an
iotest.

Note that we don't actually even need the executable bit here, we'll be
relying on the ability to run this module as a script using Python CLI
arguments. No chance it gets misunderstood as an actual iotest that way.

(It's named, not in tests/, doesn't have the execute bit, and doesn't
have an execution shebang.)

Signed-off-by: John Snow <jsnow@redhat.com>

---

(1) I think that the test file discovery logic and skip list belong together,
    and that those items belong in iotests/. I think they also belong in
    whichever directory pylintrc and mypy.ini are in, also in iotests/.

(2) Moving this logic into python/tests/ is challenging because I'd have
    to import iotests code from elsewhere in the source tree, which just
    inverts an existing problem I have been trying to rid us of --
    needing to muck around with PYTHONPATH or sys.path hacking in python
    scripts. I'm keen to avoid this.

(3) If we moved all python tests into tests/ and gave them *.py
    extensions, we wouldn't even need the test discovery functions
    anymore, and all of linters.py could be removed entirely, including
    this execution shim. We could rely on mypy/pylint's own file
    discovery mechanisms at that point. More work than I'm up for with
    just this series, but I could be coaxed into doing it if there was
    some promise of not rejecting all that busywork ;)

Signed-off-by: John Snow <jsnow@redhat.com>
---
 tests/qemu-iotests/linters.py | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/tests/qemu-iotests/linters.py b/tests/qemu-iotests/linters.py
index f6a2dc139fd..191df173064 100644
--- a/tests/qemu-iotests/linters.py
+++ b/tests/qemu-iotests/linters.py
@@ -16,6 +16,7 @@
 import os
 import re
 import subprocess
+import sys
 from typing import List, Mapping, Optional
 
 
@@ -81,3 +82,20 @@ def run_linter(
 
     return p.returncode
 
+
+def main() -> int:
+    """
+    Used by the Python CI system as an entry point to run these linters.
+    """
+    files = get_test_files()
+
+    if sys.argv[1] == '--pylint':
+        return run_linter('pylint', files)
+    elif sys.argv[1] == '--mypy':
+        return run_linter('mypy', files)
+
+    raise ValueError(f"Unrecognized argument(s): '{sys.argv[1:]}'")
+
+
+if __name__ == '__main__':
+    sys.exit(main())
-- 
2.31.1