tests: Add docker container and script for tests

Additions:
- /docker/Dockerfile.test which runs the tests inside a linux container
  with python 3.10
- /scripts/run_tests.sh runs the above

Documentation:
- How to use the above

Author: nicklafleur

CONTRIBUTING.rst

@@ -25,6 +25,15 @@ We use `inline-snapshot` for E2E and integration tests, to prevent unexpected ch
 
 If pytest terminates before reporting the test failures, it likely hit a case where mutmut calls `os._exit(...)`. Try looking at these calls first for troubleshooting.
 
+Running the tests in a container
+--------------------------------
+
+Tests are run in CI using a Linux container, if you are not running natively on Linux, you can run the tests in a container using the following script:
+
+.. code-block:: console
+
+    ./scripts/run_tests.sh
+
 Running your local version of Mutmut against a test codebase
 ------------------------------------------------------------
 

docker/Dockerfile.test

@@ -0,0 +1,14 @@
+FROM python:3.10.19-slim-trixie AS base
+
+WORKDIR /mutmut
+
+COPY --from=ghcr.io/astral-sh/uv:latest /uv /uvx /bin/
+
+ENV UV_PROJECT_ENVIRONMENT=/opt/venv
+
+COPY . .
+
+RUN uv sync --group dev
+
+ENTRYPOINT ["uv", "run", "pytest"]
+CMD ["--verbose"]

scripts/run_tests.sh

@@ -0,0 +1,5 @@
+#!/bin/bash
+set -e
+cd "$(dirname "$0")/.."
+docker build -t mutmut -f ./docker/Dockerfile.test .
+docker run --rm -t -v "$(pwd)":/mutmut mutmut "$@"