README.md

Pytest Dagger Toolchain

A toolchain for testing Python application with automatic OpenTelemetry tracing

This toolchain automatically injects a pytest_otel library for test tracing visibility in Dagger TUI and Dagger Cloud. No configuration required.

Usage:

On a python project, using pytest as the test runner:

• initialize a dagger module if not already done: dagger init .
• install the pytest toolchain: dagger toolchain install github.com/dagger/pytest
• run tests: dagger check pytest:test. It will:
  • creates an Alpine based container with uv
  • install your project dependencies using uv sync (a cache volume is set)
  • inject the pytest_otel dependency for automatic test tracing
  • run pytest

Example, using fastly/fastly-cli:

$ git clone github.com/fastly/fastly-cli

$ cd fastly-cli

$ # Initialize an empty dagger module
$ dagger init

Initialized module fastapi-cli in ~/dev/src/github.com/fastapi/fastapi-cli

$ # Add the pytest toolchain
$ dagger toolchain install github.com/dagger/pytest

toolchain installed

$ # Run tests, with tracing enabled
$ dagger check
✔ pytest:test 17.4s ⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣧⣿⣿⣿⣿⣿⣿⣿⡆⡄⣿⣿⡄ OK