🔌 REST API Testing – Automated Test Suite (Python + Pytest + Requests)

Automated API test suite built with Python, Pytest, and the requests library, covering CRUD operations, authentication endpoints, and negative/error scenarios against a live REST API.

Target API under test: reqres.in — a free, hosted REST API maintained specifically for testing and learning purposes. This project uses its public demo endpoints, which require no signup, no API key, and no rate-limit headaches, making it easy for anyone to clone this repo and run the suite immediately.

Note on the API under test: reqres.in's demo endpoints echo create/update requests back with a realistic response (correct status code, generated id, createdAt/updatedAt timestamps) but do not persist the data server-side. This is by design for a public demo API. The tests in this suite are written accordingly — they validate the contract (status codes, response schema, headers, field values in the response) rather than asserting real persistence across requests, which is exactly what you'd need to adapt if pointing this framework at a real backend.

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📌 What This Project Demonstrates

• Clean separation between API client logic and test logic (a lightweight "API client" layer, similar in spirit to Page Object Model for UI tests)
• JSON Schema validation of API responses (jsonschema library)
• Status code, header, and response body assertions
• Positive AND negative test design (invalid IDs, missing fields, bad auth)
• Data-driven testing with @pytest.mark.parametrize
• Test markers for smoke vs. regression runs
• HTML test reports
• CI pipeline via GitHub Actions

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🗂️ Project Structure

api-testing-reqres/
├── README.md
├── requirements.txt
├── pytest.ini
├── conftest.py                      # Shared fixtures (API client, base URL)
├── api_client/
│   ├── __init__.py
│   └── reqres_client.py              # Thin wrapper around `requests` calls
├── schemas/
│   ├── single_user_schema.json       # Expected JSON shape for one user
│   ├── list_users_schema.json        # Expected JSON shape for paginated user list
│   └── list_colors_schema.json       # Expected JSON shape for /api/unknown
├── tests/
│   ├── __init__.py
│   ├── test_get_users.py             # GET (list + single + 404 handling)
│   ├── test_create_user.py           # POST
│   ├── test_update_user.py           # PUT / PATCH
│   ├── test_delete_user.py           # DELETE
│   └── test_auth.py                  # /api/register and /api/login
├── .github/workflows/tests.yml       # CI pipeline
└── reports/                          # Generated HTML test reports (git-ignored)

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⚙️ Setup

git clone https://github.com/dmimasruz/api-testing-reqres.git
cd api-testing-reqres

python -m venv venv
source venv/bin/activate      # Windows: venv\Scripts\activate

pip install -r requirements.txt

No API key or environment variables needed — the demo endpoints are open.

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▶️ Running the Tests

pytest                                                   # full suite
pytest -m smoke                                          # smoke tests only
pytest --html=reports/report.html --self-contained-html  # with HTML report

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🧪 Test Cases Covered

ID	Test Case	Endpoint	Marker
TC01	List users returns 200 and correct pagination shape	GET /api/users?page=2	smoke
TC02	List users response matches JSON schema	GET /api/users?page=2	regression
TC03	Get single existing user returns correct data	GET /api/users/2	smoke
TC04	Get single user response matches JSON schema	GET /api/users/2	regression
TC05	Get non-existent user returns 404	GET /api/users/23	smoke
TC06	List colors (unknown resource) returns valid schema	GET /api/unknown	regression
TC07	Create user returns 201 with correct echoed fields	POST /api/users	smoke
TC08	Create user response includes generated id and timestamp	POST /api/users	regression
TC09	Update user (PUT) returns 200 with updated fields	PUT /api/users/2	smoke
TC10	Partial update user (PATCH) returns 200	PATCH /api/users/2	regression
TC11	Delete user returns 204 with empty body	DELETE /api/users/2	smoke
TC12	Successful registration returns id + token	POST /api/register	smoke
TC13	Registration without password fails with 400	POST /api/register	regression
TC14	Successful login returns a token	POST /api/login	smoke
TC15	Login without password fails with 400	POST /api/login	regression
TC16	Data-driven: multiple valid user IDs all return 200	GET /api/users/:id	regression

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🔧 Tech Stack

• Python 3.10+
• requests (HTTP client)
• pytest (test runner)
• jsonschema (response schema validation)
• pytest-html (reporting)

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🚀 Next Steps (Ideas for Extending This Project)

• Add response-time/performance assertions (e.g. assert response.elapsed.total_seconds() < 1)
• Add contract testing against the published OpenAPI spec
• Point the same framework at a real backend (e.g. a project's own Flask/FastAPI app) to test actual persistence
• Add authentication token reuse across a session for endpoints that require it
• Integrate with the UI test suites in the other portfolio repos (e.g. verify a user created via API appears correctly in the UI)