Testing and CI/CD: From Code to Continuous Delivery

Testing and CI/CD are not separate rituals; they form a continuous feedback loop. When developers push code, automated checks verify safety and usefulness. A fast, reliable pipeline reduces bugs in production and makes releases predictable. This guide outlines a practical path from writing code to delivering it with confidence.

How a CI/CD pipeline works

A typical flow has several stages: commit, build, test, and deploy. Each stage runs automatically when changes arrive. The goal is to fail fast and give clear feedback to the team. Keep artifacts small, tests independent, and logs readable.

  • Automated tests cover unit, integration, and end-to-end scenarios
  • Linting, security checks, and dependency checks catch issues early
  • Build and artifact storage provide traceability for the release

What to test at each stage

Local development should cover unit tests and quick checks. In CI, run broader tests: unit, integration, and UI tests, plus performance checks when needed. In staging, verify deployment and user flows with realistic data.

  • Unit tests fastly validate small units of code
  • Integration tests verify how parts work together
  • End-to-end tests simulate real user scenarios
  • Security and quality checks guard against common flaws

Practical tips

  • Keep tests fast and reliable; slow tests slow delivery
  • Isolate tests and use mocks where appropriate
  • Avoid relying on real external services in unit tests
  • Track flaky tests and fix them quickly
  • Use parallel execution and caching to speed runs

A simple, well-documented flow helps everyone. For example, on push to main, run lint, unit tests, and integration tests, then build artifacts and push to a registry. On pull requests, run the same checks to catch issues before merging.

Key takeaways

  • Automation at every stage catches issues early and keeps delivery steady.
  • Tests should be fast, reliable, and informative to guide fixes.
  • A well designed pipeline supports fast feedback, traceability, and safe rollbacks.