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This article demonstrates various tests for user authentication and post-related operations in our API. We begin by testing user creation and login, then move on to verifying post-related endpoints. Throughout the guide, notice how fixtures are used to streamline authentication and how tests are organized to promote clarity and maintainability.

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User Authentication Tests

Below is a sample test for creating a user and logging in: 
def test_create_user(client):
    res = client.post(
        "/users/", json={"email": "[email protected]", "password": "password123"}
    )
    new_user = schemas.UserOut(**res.json())
    assert new_user.email == "[email protected]"
    assert res.status_code == 201

def test_login_user(test_user, client):
    res = client.post(
        "/login", data={"username": test_user["email"], "password": test_user["password"]}
    )
Result output: 
collected 7 items

tests/test_users.py::test_create_user PASSED
tests/test_users.py::test_login_user PASSED
tests/test_users.py::test_incorrect_login[[email protected]] PASSED
tests/test_users.py::test_incorrect_login[[email protected]] PASSED
tests/test_users.py::test_incorrect_login[None-password123-422] PASSED
tests/test_users.py::test_incorrect_login[[email protected]] PASSED

warnings summary =====================
The example above shows the use of fixtures and assertions to validate user creation and login processes. This practice ensures each test runs independently with proper setup and teardown.
For clarity, here is the corrected version of the user test code that can be stored in a dedicated module: 
def test_create_user(client):
    res = client.post(
        "/users/", json={"email": "[email protected]", "password": "password123"}
    )
    new_user = schemas.UserOut(**res.json())
    assert new_user.email == "[email protected]"
    assert res.status_code == 201

def test_login_user(test_user, client):
    res = client.post(
        "/login", data={"username": test_user["email"], "password": test_user["password"]}
    )
Result output: 
collected 7 items

tests/test_users.py::test_create_user PASSED
tests/test_users.py::test_login_user PASSED
tests/test_users.py::test_incorrect_login[[email protected]] PASSED
tests/test_users.py::test_incorrect_login[[email protected]] PASSED
tests/test_users.py::test_incorrect_login[None-password123-422] PASSED
tests/test_users.py::test_incorrect_login[[email protected]] PASSED

warnings summary

​
Post Endpoints Testing

When dealing with posts, note that every POST path operation requires authentication. For example, the posts retrieval endpoint is defined as follows: 
@router.get("/", response_model=List[schemas.PostOut])
def get_posts(
    db: Any = Depends(get_db),
    current_user: int = Depends(oauth2.get_current_user),
    limit: int = 10,
    skip: int = 0,
    search: Optional[str] = ""
):
    # Implementation code here
Result output: 
collected 7 items
tests/test_users.py::test_create_user PASSED
tests/test_users.py::test_login_user PASSED
tests/test_users.py::test_incorrect_login[[email protected]] PASSED
...
warnings summary
For endpoints requiring authentication, using fixtures to simulate token generation is a more efficient approach than performing a full login request for every test.
Instead of making a full API call to log in and retrieve a token for every test, it is more efficient to import the token creation function directly from the OAuth2 module. This allows simulation of token generation without going through the complete login process. Consider the following implementation: 
def create_access_token(data: dict):
    to_encode = data.copy()
    expire = datetime.utcnow() + timedelta(minutes=ACCESS_TOKEN_EXPIRE_MINUTES)
    to_encode.update({"exp": expire})
    encoded_jwt = jwt.encode(to_encode, SECRET_KEY, algorithm=ALGORITHM)
    return encoded_jwt

def verify_access_token(token: str, credentials_exception):
    # Verification logic
    pass
Result output: 
collected 7 items
tests/test_users.py::test_create_user PASSED
...
warnings summary

​
Configuring Fixtures with conftest.py

In our conftest.py, we set up a fixture to create a test user. This fixture sends a POST request to the user creation endpoint and returns the user data along with their password for further testing: 
import pytest

@pytest.fixture
def test_user(client):
    user_data = {"email": "[email protected]", "password": "password123"}
    res = client.post("/users/", json=user_data)
    assert res.status_code == 201

    new_user = res.json()
    new_user["password"] = user_data["password"]
    return new_user
Result output: 
collected 7 items
tests/test_users.py::test_create_user PASSED
...
warnings summary ==================================
Next, create a fixture that generates an access token for the test user using the imported function: 
@pytest.fixture
def token(test_user):
    return create_access_token({"user_id": test_user["id"]})
Result output: 
collected 7 items
tests/test_users.py::test_create_user PASSED
...
Then, set up an authorized_client fixture that modifies the original client’s headers to include the access token for endpoints requiring authentication: 
import pytest

@pytest.fixture
def authorized_client(client, token):
    client.headers = {
        **client.headers,
        "Authorization": f"Bearer {token}"
    }
    return client
Result output: 
collected 7 items
tests/test_users.py::test_create_user PASSED
...

​
Testing the Retrieval of Posts

Now that authentication is handled by our fixtures, we can write a test for retrieving posts using the authorized client. This test sends a GET request to the /posts/ endpoint, prints the response data for inspection, and asserts that the response status code is 200: 
def test_get_all_posts(authorized_client):
    res = authorized_client.get("/posts/")
    print(res.json())
    assert res.status_code == 200
Result output: 
collected 7 items
tests/test_posts.py::test_get_all_posts PASSED
When running this test, the output may show an empty array if there are no posts in your test database. In that case, ensure you create test posts before executing this test to confirm data retrieval works correctly.
To run the tests, use a command similar to the following: 
(venv) C:\Users\sanje\Documents\Courses\fastapi>pytest tests\test_posts.py -v -s
Result output: 
platform win32 -- Python 3.9.5, pytest-6.2.5, ...
collected 1 item

tests/test_posts.py::test_get_all_posts [] PASSED

===================================================================== warnings summary =====================================================================
...

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Summary

This article demonstrated the following:
  • Organizing tests for user authentication and post endpoints.
  • Simulating authentication efficiently using fixtures.
  • Verifying test results with proper assertions.
In the upcoming article, we will explore creating test posts and validating the retrieved data. For more technical guides and best practices, be sure to check the Kubernetes Documentation and other developer resources.

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