Benchmarking

anyplotlib ships two benchmark suites that cover the Python serialisation pipeline (tests/test_benchmarks_py.py) and JS render performance via headless Chromium (tests/test_benchmarks.py).

Running locally

# Python suite — fast (~30 s), no browser needed
uv run pytest tests/test_benchmarks_py.py -v

# JS suite — requires Playwright + Chromium (~3 min)
uv run pytest tests/test_benchmarks.py -v

# Add 4 096² / 8 192² image scenarios (slow, opt-in)
uv run pytest tests/test_benchmarks_py.py --run-slow -v

Updating committed baselines

Run --update-benchmarks after an intentional performance change to refresh tests/benchmarks/baselines.json:

uv run pytest tests/test_benchmarks_py.py tests/test_benchmarks.py \
    --update-benchmarks -v

Commit the result so local runs and the performance table stay accurate.

CI — hardware-agnostic comparison

Absolute ms values are meaningless across different runners, so CI never compares against the committed baselines file. Instead it checks out both the base branch and the head branch on the same runner in the same job and compares them — only the ratio matters, hardware differences cancel out.

1. Checkout BASE  →  pytest --update-benchmarks --baselines-path /tmp/ci_baselines.json
2. Checkout HEAD  →  pytest --baselines-path /tmp/ci_baselines.json
   Pass / fail is based on the ratio, not absolute ms.

The --baselines-path flag redirects reads and writes without touching the committed tests/benchmarks/baselines.json.

Threshold: 1.50 × (50 % slower → failure, 25 % → warning).