Article: Organize api tests in GitLab CI/CD.

[aleksandr-kotlyar]

Plan

GitLab CI/CD & Docker

1. How GitLab works. What for are yml instructions, how it listens this, links links links 1,2,3,4 to the official docs about gitlab runners and executors. Describe why docker executor is the best for the most of common cases.
2. Create simple script with installing dependencies in it to show the work of CI/CD. Describe why it's a bad practice. And move to the next step with best practice with Docker.
3. Create simple Dockerfile with dependencies. Describe what base distributives exist and what's the difference between them or find a link to the article explains this.
4. Make and push Docker image to GitLab Container Registry.
5. Show how to use your own image from registry in CI/CD scripts.

Tests and GitLab CI/CD

1. Simple job with image from registry.
2. Schedule tests nightly.
3. Tests on push is a time waste. Good at start. Bad in the distance. Describe how to still run them but not on every push.
4. Trigger tests from another project pipeline.
5. Show the CI/CD variables and manual runs. As example - custom test suite or special environment.
6. Schedule tests for different test environments.
7. Differentiate test:test stages & jobs for each test environment in schedules to easy find them in Pipelines and Jobs list.
8. Schedule more test suites. Mono-repository example.
9. Parallel job execution on the same runners - link to official docs.
10. Big daddy pipelines. Group test suites which can be executed in parallel on the same environment and make the pipeline from all of these groups.