GitHub Actions basics

Summary

GitHub's built-in CI/CD system — YAML workflow files that automatically run tests, builds or deployments on events like pushes and pull requests. Workflows can run tests, linting, builds, security checks, releases, and deployments automatically, making them a foundation for repeatable engineering processes.

• 1Add a simple workflow that runs `npm test` on every push. Test the result on both a successful path and an invalid or unexpected input.
• 2Learn the basic YAML structure: triggers, jobs, and steps. Focus on understanding the underlying reason it works, not only memorizing the definition.
• 3Explore the GitHub Actions marketplace for prebuilt actions (deploy, lint, etc.).