tony 00-scan
Profile, detect, hypothesize. This phase only reads the suite and only writes JSON to the memory directory. No test is edited here.
$ARGUMENTS may scope the run to a path or marker, set --runs=N (baseline
sample count, default 5), --force to ignore the idempotency token, and
--memory-dir to override the memory location.
Step 1: Preflight
Detect preferred tools (rg/ag/fd/jq/uv/uvx) and read the project's
own test command from AGENTS.md, CLAUDE.md, justfile, tox.ini, or
pyproject.toml. Do not hardcode a runner. Record the resolved command; every
later phase reuses it. Substitute it wherever this file writes pytest.
Step 2: Resolve memory and check idempotency
Resolve the memory directory per ../../references/memory-schema.md
(repo-root .pytest-optimizer/, gitignored; XDG fallback). Compute the
idempotency token (git HEAD + collection node-ids + pytest/plugin versions +
environment fingerprint). If state.json shows scan completed with an unchanged
token and
hypotheses.json exists, report "already scanned" and stop — unless --force.
Step 3: Detect capabilities
Probe the installed pytest and plugins against
../../references/version-matrix.md. Write
capabilities.json. Use only available features below; fall back as the matrix
directs (e.g. no --durations-min pre-6.1 → post-filter rows).
Step 4: Establish the baseline and noise band
Run the suite serially, cache disabled, --runs times, and record total
wall-time each run:
pytest -p no:cacheprovider -p no:randomly -q
Compute the median and MAD of the per-run totals; set the noise band
(median + k·MAD, default k = 3) and the ~50ms trust floor. Write the env
fingerprint, versions, capabilities, and the band to baseline.json. See
../../references/durations-parsing.md.
Step 5: Profile slowest tests and fixtures
Capture per-phase timings and bucket rows by the when token (call vs
setup/teardown), de-duplicating by (nodeid, when):
pytest --durations=0 --durations-min=0.005 -p no:cacheprovider -p no:randomly
Rank slowest test bodies (call, H01) and slowest fixture
setup/teardown (setup/teardown, H02). For shared higher-scope fixtures whose
cost is billed to one nodeid (H03), note the attribution; offer the opt-in timing
plugin if precise per-fixture cost is needed. Persist the timings to
baseline.json.
Step 6: Run the static detectors
Work through ../../references/heuristic-catalog.md, using
../../references/fixture-analysis.md for the fixture recipes and
../../references/parametrize-convention.md for the typing/
parametrize gaps:
- Fixtures: unused (H08/H09/H41), mis-scoped (H10/H13), duplicate (H11), autouse (H12/H15), mark-on-fixture (H43), empty conftest (H42).
- Collection/capability errors (H14/H22/H44).
- Typing and parametrize gaps (H26–H32).
- I/O, sleep, markers, timeouts (H15/H33/H37/H39/H40).
- Recomputation and duplication (H24/H25/H34/H35/H36/H38).
Apply the getfixturevalue guard (H09) before proposing any fixture deletion.
Step 7: Emit hypotheses
Write hypotheses.json: one entry per firing detector, each tagged with its
heuristic id, the goal(s) it addresses, the raw evidence, and prior risk/effort.
Do not estimate impact here — 01-benchmark measures it. Update state.json
(phase=scan, completed.scan=true, token).
Step 8: Report
Emit the 00-scan sections from
../../references/output-contract.md: a hero block, then
## Environment, ## Baseline, ## Slowest tests, ## Slowest fixtures,
## Hypotheses. Close with an AskUserQuestion panel offering to benchmark the
hypotheses, narrow scope, or stop.