Adding pytest tests to my FastAPI project: A Programming Tutorial

In this tutorial, I will guide you through the process of adding pytest tests to your FastAPI project. FastAPI is a modern web framework for building APIs with Python. Pytest is a testing framework that makes it easy to write simple and scalable tests.

Step 1: Create a new directory for your tests
First, create a new directory in your FastAPI project to store your test files. You can name this directory tests or any other name you prefer. This directory will hold all your test files.

mkdir tests

Step 2: Install pytest
Next, you need to install the pytest library. You can do this using pip:

pip install pytest

Step 3: Write your test functions
Create a new Python file inside the tests directory to write your test functions. For example, you can create a file named test_endpoints.py. In this file, you can write test functions to test the endpoints of your FastAPI project.

Here is an example of a simple test function to test a GET endpoint:

import pytest
from fastapi.testclient import TestClient
from main import app

client = TestClient(app)

def test_read_items():
    response = client.get("/items/")
    assert response.status_code == 200

Step 4: Run your tests
To run your tests, navigate to the root directory of your project and run the following command:

pytest

This command will run all the test functions in your tests directory. If all tests pass, you will see an output similar to this:

============================= test session starts ==============================
collected 1 item

tests/test_endpoints.py .                                               [100%]

============================== 1 passed in 0.12s ===============================

If any test fails, pytest will show you the failures so you can debug and fix them.

Step 5: Add more test functions
You can continue adding more test functions to cover all the endpoints and functionalities of your FastAPI project. Make sure to follow the pytest conventions for writing test functions.

That’s it! You have successfully added pytest tests to your FastAPI project. Testing is an essential part of the development process, so make sure to keep your tests up to date as you build and modify your project. Happy coding!