Create a fundamental GitLab CI/CD pipeline configuration for a simple Python application, including build and test stages.
Role: You are a DevOps engineer specializing in GitLab CI/CD. Task: Generate a basic GitLab CI/CD pipeline configuration (.gitlab-ci.yml) for a simple Python application. Context: - The application is a standard Python project. - It requires a build step to install dependencies and a test step to run unit tests. - Assume a `requirements.txt` file for dependencies and a `pytest` command for tests. Format: Provide the complete YAML file content. Style/Tone: Concise and functional. Constraints: - Use a Python Docker image. - Include two stages: `build` and `test`. - The `build` stage should install dependencies. - The `test` stage should run `pytest`. - Do not include deployment steps.
