Add pytest-cov coverage measurement and tests for log_utils.py

[Copilot]

No coverage measurement existed in the test suite, and chainweaver/log_utils.py (83 lines, 4 public functions) had zero dedicated tests.

Changes

pyproject.toml

• Added addopts to [tool.pytest.ini_options] to enforce coverage on every pytest run:

  addopts = "--cov=chainweaver --cov-report=term-missing --cov-fail-under=80"

tests/test_log_utils.py (new)

• 20 tests across 4 classes covering every function in log_utils.py:
  • TestGetLogger — return type, name binding, identity semantics
  • TestLogStepStart — INFO level, step index, tool name, inputs, START marker
  • TestLogStepEnd — INFO level, step index, tool name, outputs, END marker
  • TestLogStepError — ERROR level, step index, tool name, exception type/message, ERROR marker
• Uses caplog fixture for log capture; consistent with existing test conventions

Result

Full suite: 66 tests, 98.6% coverage — threshold of 80% is met with significant headroom.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Add pytest-cov coverage measurement and tests for log_utils.py</issue_title>
<issue_description>## Category
code-quality | Priority: P2 | Effort: S (1–2 days)

Context

The test suite (503 lines in test_flow_execution.py + 120 lines in test_registry.py) appears thorough but there's no coverage measurement to verify which lines and branches are actually tested. Additionally, chainweaver/log_utils.py has zero tests.

Evidence:

• No pytest-cov in dev dependencies
• ci.yml runs pytest tests/ -v with no coverage flags
• chainweaver/log_utils.py (83 lines) — get_logger(), log_step_start(), log_step_end(), log_step_error() have no dedicated tests
• No coverage reporting or threshold enforcement

What to do

Add pytest-cov for coverage measurement, set a coverage threshold in CI, and add missing tests for log_utils.py.

Implementation steps

1. Add pytest-cov to dev dependencies in pyproject.toml:

   [project.optional-dependencies]
   dev = [
       "pytest>=7.0",
       "pytest-cov>=4.0",
   ]

2. Update pytest config in pyproject.toml:

   [tool.pytest.ini_options]
   testpaths = ["tests"]
   python_files = ["test_*.py"]
   python_classes = ["Test*"]
   python_functions = ["test_*"]
   addopts = "--cov=chainweaver --cov-report=term-missing --cov-fail-under=80"

3. Update CI to show coverage in test output:
   The addopts in pyproject.toml will automatically apply. No changes needed to CI commands unless you want a separate coverage artifact.

4. Add tests for log_utils.py — create tests/test_log_utils.py:

   • Test get_logger() returns a logging.Logger with correct name
   • Test log_step_start() emits INFO log with correct format
   • Test log_step_end() emits INFO log with correct format
   • Test log_step_error() emits ERROR log with correct format
   • Use caplog pytest fixture to capture log output

Files to modify

• pyproject.toml — update dev deps + pytest config
• tests/test_log_utils.py — new test file

Definition of Done

• pytest-cov in dev dependencies
• --cov=chainweaver --cov-report=term-missing --cov-fail-under=80 in pytest addopts
• tests/test_log_utils.py created with tests for all 4 functions in log_utils.py
• Coverage threshold passes (≥80%)
• CI is green

Dependencies

None — but benefits from #38 (Ruff) and #39 (mypy) being done first so new test code is also linted/typed.

Execution order

Issue 6 of 7 — completes the testing infrastructure.

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Related: #38 (Ruff), #39 (mypy) | Part of the P4 initiative to improve both AI-agent readiness and SWE best practices.</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Add pytest-cov coverage measurement and tests for log_utils.py #42

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[Copilot]

Pull request overview

This PR strengthens the project’s testing discipline by enabling automatic coverage measurement on every pytest run and adding dedicated unit tests for chainweaver.log_utils (the structured step-logging helpers used by the executor).

Changes:

• Enforce coverage measurement + minimum threshold via pytest config (--cov=chainweaver --cov-report=term-missing --cov-fail-under=80).
• Add a new tests/test_log_utils.py suite that exercises get_logger, log_step_start, log_step_end, and log_step_error using caplog.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
pyproject.toml	Adds pytest addopts so coverage is always collected and a minimum threshold is enforced.
tests/test_log_utils.py	Adds targeted tests validating that log utilities emit correctly leveled, structured messages.

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