At what stage of the CI/CD process in GitLab does automatic testing occur?

In GitLab, automated tests are usually run during the test stage in the CI/CD pipeline. This stage is executed after the build stage and is intended to verify code correctness using unit tests, integration tests, and other testing types. In .gitlab-ci.yml, it might look like:

stages:
  - build
  - test
  - deploy

test_job:
  stage: test
  script:
    - ./run_tests.sh

Thus, tests are executed in a separate stage that runs automatically on each commit or branch merge.