ARROW-16548: [Python] Add pytest.mark.parquet to all tests under tests/parquet package

[raulcd]

If we built arrow and pyarrow without PARQUET and tried to run the PARQUET tests. The first test being executed was not correctly marked.

> /home/raulcd/open_source/arrow/python/pyarrow/tests/conftest.py(244)pytest_runtest_setup()
-> for mark in item.iter_markers():
(Pdb) item
<Function test_parquet_invalid_version>
(Pdb) [x for x in item.iter_markers()]
[]
(Pdb)

Meaning the test was not correctly skipped. This was found on the minimal builds PR: #13113 on this job failures: https://github.com/ursacomputing/crossbow/runs/6407176338?check_suite_focus=true

All tests under the parquet package are on the structure:

• parquet
  ├── test_basic.py
  ├── test_compliant_nested_type.py
  ├── test_dataset.py
  ├── test_data_types.py
  ├── test_datetime.py
  ├── test_encryption.py
  ├── test_metadata.py
  ├── test_pandas.py
  ├── test_parquet_file.py
  └── test_parquet_writer.py

The implementation marks all the individual tests that are on this structure with the parquet dataset mark correctly.

[github-actions]

https://issues.apache.org/jira/browse/ARROW-16548

[github-actions]

⚠️ Ticket has not been started in JIRA, please click 'Start Progress'.

[raulcd]

@jorisvandenbossche other solutions that fix this issue could be:

• Add the pytestmark = pytest.mark.parquet to each test file individually instead of to the common file
• Add the pytestmark import (even when we are not using it) on each individual test file (from pyarrow.tests.parquet.common import pytestmark)

I was going in a rabbit hole on importlib and load_module but I don't think is worth the effort to spend more time on this having three possible solutions.
One nice thing is I had to go back to a talk I gave at PyCon Spain on how import works :)

[jorisvandenbossche]

Hmm, I would actually have expected that the pytestmark = .. in the tests/parquet/__init__.py would ensure this applies that mark to all the tests in that directory (and not the one in common.py).
But if that seems to not work correctly in practice, I think adding pytestmark = pytest.mark.parquet to every file might be the most "low tech" solution?

[raulcd]

Thanks @jorisvandenbossche . I was able to reproduce the issue on each one of the test files individually. This solution solves the test failures when PARQUET is not enabled.

[pitrou]

+1 from me assuming that it does solve the issue.

[ursabot]

Benchmark runs are scheduled for baseline = 52a051b and contender = c032290. c032290 is a master commit associated with this PR. Results will be available as each benchmark for each run completes.
Conbench compare runs links:
[Finished ⬇️0.0% ⬆️0.0%] ec2-t3-xlarge-us-east-2
[Finished ⬇️0.08% ⬆️0.0%] test-mac-arm
[Finished ⬇️0.36% ⬆️0.0%] ursa-i9-9960x
[Finished ⬇️0.67% ⬆️0.0%] ursa-thinkcentre-m75q
Buildkite builds:
[Finished] c032290b ec2-t3-xlarge-us-east-2
[Finished] c032290b test-mac-arm
[Finished] c032290b ursa-i9-9960x
[Finished] c032290b ursa-thinkcentre-m75q
[Finished] 52a051b1 ec2-t3-xlarge-us-east-2
[Finished] 52a051b1 test-mac-arm
[Finished] 52a051b1 ursa-i9-9960x
[Finished] 52a051b1 ursa-thinkcentre-m75q
Supported benchmarks:
ec2-t3-xlarge-us-east-2: Supported benchmark langs: Python, R. Runs only benchmarks with cloud = True
test-mac-arm: Supported benchmark langs: C++, Python, R
ursa-i9-9960x: Supported benchmark langs: Python, R, JavaScript
ursa-thinkcentre-m75q: Supported benchmark langs: C++, Java

[jorisvandenbossche]

Ah, we can't assign two marks this way (it is redefining the same variable), it should be something like pytestmark = [..., ...] I think