This tool

1. computes jobs the Travis-CI would run
2. generates docker image (that can be customized) for each job
3. runs each job

What it means:

• no switching of PHP versions to test your library
• no forgetting to run a specific job
• prepare everything locally and verify the build passes without hassle
• clean testing environment very time

This does not replace a build system (which would be able to run identical tasks on CI and local), but even a build system wouldn't be able to guarantee executing full Travis matrix with all jobs.

• clone the project
• install dependencies using composer
• build docker images in docker-images/ using docker-compose build
  • Pro-Tip: you can customize them!
• run the executable bin/travis-local in desired directory