pytest-telescope

Declared inputs. Isolated tests. Focused reruns.

Put input declarations beside pytest cases. Each actual case, including each parametrized variant, runs in a fresh Linux Docker worker and has its own reusable successful result. Two cases in the same file can declare different resources and rerun independently.

import pytest


@pytest.mark.telescope(inputs=["data/red.json"], bundles=["pricing"])
def test_red(): ...


@pytest.mark.telescope(inputs=["data/blue.json"], bundles=["pricing"])
def test_blue(): ...

Unmarked cases see and hash the whole project-file snapshot. Literal inputs or bundles marker fields narrow that scope. Declarations at module, class, function, and parameter levels add together with project defaults. cache=False alone stays broad. The containing test source and configuration are always included.

Try it

Requirements: Linux, Python 3.11+, and permission to build/run Linux containers through a local Docker daemon's Unix socket. Runtime preparation needs network; workers have no network.

python -m venv .venv
. .venv/bin/activate
python -m pip install pytest-telescope==0.1.0a2

Follow the complete runnable quickstart for copyable application code, tests, JSON, and TOML. It demonstrates cold/warm reuse, same-file independent inputs, parameter-specific declarations, shared bundles, broad invalidation, and an undeclared read failure. The base files are also in examples/quickstart.

From your configured project root:

python -m pytest_telescope runtime
python -m pytest_telescope plan
python -m pytest_telescope run --explain -- -q
python -m pytest_telescope run --explain -- -q

plan previews static scopes. run collects actual cases inside an isolated worker; each execution then starts with only that case's scope. A warm inventory/result hit starts no worker containers. Summaries distinguish collection, fresh execution, cached results, failures, and unselected cases. New files or parametrized cases cannot hide behind an old result.

Know the boundary

Every case gets a fresh pytest session, so module/class/session fixtures are recreated per case. Tests relying on cross-case mutable state need rewriting. Shared import and parametrization resources must be declared for every narrow consumer, typically in project defaults or bundles. Application files and host virtual environments are not installed into the prepared runtime.

Filesystem isolation does not establish universal determinism. Make clock, randomness, and native/external-state assumptions reproducible or mark affected cases cache=False. Use run --force to execute again or run --no-cache to bypass reuse and recording.

The dedicated CLI starts no host pytest session. pytest --telescope also routes to workers, but other plugins may execute during host pytest startup. pytest --telescope-plan is a static planning adapter. Ordinary pytest stays ordinary when telescope mode is disabled; -p no:telescope disables plugin loading entirely.

Version note: 0.1.0a2 uses the marker interface. Immutable 0.1.0a1 used file/group targets; central targets declarations must migrate to markers, defaults, and bundles. The benchmark records measured per-case cold/warm and selective reruns, including broad-case costs.

See the marker/project reference, execution contract, development guide, and publishing guide. Licensed under the MIT License.