How can the testing process be automated within a CI/CD pipeline?

Test automation in CI/CD pipelines is achieved through the following methods:

• Integration of tests into the build process: automatic tests (unit, integration, e2e) are run on each commit or pull request.
• Use of CI systems (Jenkins, GitLab CI, GitHub Actions): setting up a pipeline that includes build, test, and deploy stages.
• Parallel test execution: to speed up the process.
• Reports and notifications: automatic generation of test result reports and team notifications in case of errors.

An example of a simple config for GitHub Actions that runs tests on Python:

name: Python Tests

on: [push, pull_request]

jobs:
  test:
    runs-on: ubuntu-latest
    steps:
    - uses: actions/checkout@v2
    - name: Set up Python
      uses: actions/setup-python@v2
      with:
        python-version: '3.8'
    - name: Install dependencies
      run: pip install -r requirements.txt
    - name: Run tests
      run: pytest

Thus, tests are automatically run upon code changes, allowing quick detection of errors.