Fixture organization in FastAPI - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a simple FastAPI fixture that provides a test client.

FastAPI

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

@pytest.fixture
 def client():
    return [1](app)

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ATestClient

BFastAPI

CClientSession

DHttpClient

Attempts:

3 left

💡 Hint

Common Mistakes

Using FastAPI class instead of TestClient

Using unrelated HTTP client classes

The TestClient is used to create a test client for FastAPI apps in fixtures.

2fill in blank

medium

Complete the fixture to yield a database session for tests.

FastAPI

import pytest
from myapp.database import SessionLocal

@pytest.fixture
 def db_session():
    db = [1]()
    try:
        yield db
    finally:
        db.close()

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ASessionLocal

Bcreate_session

CDatabaseSession

Dget_db

Attempts:

3 left

💡 Hint

Common Mistakes

Using a function name that does not create a session

Forgetting to close the session

SessionLocal is the factory that creates new database sessions for tests.

3fill in blank

hard

Fix the error in this fixture that overrides the dependency for the database session.

FastAPI

from fastapi.testclient import TestClient
from myapp.main import app
from myapp.database import SessionLocal
import pytest
from myapp.database import get_db

@pytest.fixture
 def client_override_db():
    def override_get_db():
        db = SessionLocal()
        try:
            yield db
        finally:
            db.close()

    app.dependency_overrides[[1]] = override_get_db
    with TestClient(app) as c:
        yield c
    app.dependency_overrides.clear()

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Aoverride_get_db

BSessionLocal

Cget_db

Ddb_session

Attempts:

3 left

💡 Hint

Common Mistakes

Using the session class as the key

Using the override function as the key

The dependency_overrides dictionary keys must be the original dependency function, here get_db.

4fill in blank

hard

Fill both blanks to create a fixture that resets the database before each test.

FastAPI

import pytest
from myapp.database import Base, engine

@pytest.fixture(autouse=True)
 def reset_db():
    Base.metadata.[1](bind=engine)
    Base.metadata.[2](bind=engine)

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Adrop_all

Bcreate_all

Cinitialize

Dreset

Attempts:

3 left

💡 Hint

Common Mistakes

Reversing the order of drop_all and create_all

Using non-existent methods like initialize or reset

First, drop_all removes all tables, then create_all recreates them for a clean state.

5fill in blank

hard

Fill all three blanks to define a fixture that provides an authenticated test client.

FastAPI

import pytest
from fastapi.testclient import TestClient
from myapp.main import app
from myapp.auth import create_access_token

@pytest.fixture
 def auth_client():
    token = create_access_token(data={"sub": [1])
    headers = {"Authorization": f"Bearer [2]"}
    client = TestClient(app)
    client.headers.update([3])
    return client

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A"testuser"

Btoken

Cheaders

D"admin"

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong username string

Not updating client headers correctly

The token is created for user "testuser", then used in the Authorization header, which is added to the client headers.