[MNT] Diagnose and address long test runtimes (#1633)

[Abhishek9639]

Fixes #1633

Changes

Current CI test runs take 1–2+ hours. This PR diagnoses the bottleneck and implements several improvements:

Root Cause

The production_server tests (74 tests) make live API calls to openml.org, taking ~1h 23m in CI even with 4-worker parallelization.

Improvements

1. Global per-test timeout (pyproject.toml)

   • Added timeout = 600 (10 min) to [tool.pytest.ini_options]
   • Prevents any single test from hanging indefinitely

2. CI workflow improvements (.github/workflows/test.yml)

   • Changed --durations=20 → --durations=0 to report ALL test durations for diagnosis
   • Added explicit --timeout=600 to all 3 pytest invocations

3. Fixture optimization (tests/conftest.py)

   • Changed verify_cache_state fixture scope from function → module
   • Reduces redundant filesystem I/O (was running before/after EVERY test)

4. Benchmark script (scripts/profile_tests.sh)

   • New script for easy local test duration profiling
   • Configurable marker filters

Test Distribution Analysis

Category	Count	CI Time
All tests	368
production_server	74	~1h 23m (bottleneck)
test_server	196	excluded from CI
sklearn-only	6	~1 min
Non-server	99	fast

Verification

• All pre-commit checks pass (ruff, ruff-format, mypy)
• All 368 tests still collect correctly

[Abhishek9639]

Hii @geetu040 and @fkiraly,
Fixed the code quality checks. All pre-commit checks are now passing.
Please review it.