Testing with database in FastAPI - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a test client for FastAPI.

FastAPI

from fastapi.testclient import TestClient
from main import app

client = [1](app)

Drag options to blanks, or click blank then click option'

AAppClient

BClient

CFastClient

DTestClient

Attempts:

3 left

💡 Hint

Common Mistakes

Using a wrong client class name.

Forgetting to import TestClient.

The TestClient class from fastapi.testclient is used to create a test client for the FastAPI app.

2fill in blank

medium

Complete the code to override the database dependency in FastAPI for testing.

FastAPI

from fastapi import Depends

def override_get_db():
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()

app.dependency_overrides[[1]] = override_get_db

Drag options to blanks, or click blank then click option'

Adatabase

Bdb_session

Cget_db

Dget_database

Attempts:

3 left

💡 Hint

Common Mistakes

Using a wrong dependency name.

Not overriding the dependency before tests.

The original database dependency function is usually named get_db. We override it with our test version.

3fill in blank

hard

Fix the error in the test function to correctly use the test client and database session.

FastAPI

def test_create_item():
    response = client.post('/items/', json={'name': 'Test Item'})
    assert response.status_code == [1]
    data = response.json()
    assert data['name'] == 'Test Item'

Drag options to blanks, or click blank then click option'

A201

B404

C400

D200

Attempts:

3 left

💡 Hint

Common Mistakes

Expecting 200 instead of 201.

Confusing client errors with success codes.

When creating a new item, the API should return status code 201 Created to indicate success.

4fill in blank

hard

Fill both blanks to create a test database session and override the app dependency.

FastAPI

from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker

SQLALCHEMY_DATABASE_URL = "sqlite:///./test.db"
engine = create_engine(SQLALCHEMY_DATABASE_URL, connect_args=[1])
TestingSessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)

def override_get_db():
    db = TestingSessionLocal()
    try:
        yield db
    finally:
        db.close()

app.dependency_overrides[[2]] = override_get_db

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A{"check_same_thread": False}

B{"check_same_thread": True}

Cget_db

Ddatabase_session

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong connect_args for SQLite.

Overriding the wrong dependency.

SQLite requires check_same_thread=False for testing with multiple threads. The dependency to override is get_db.

5fill in blank

hard

Fill all three blanks to write a test that creates an item and checks the database directly.

FastAPI

def test_create_and_check_db():
    response = client.post('/items/', json=[1])
    assert response.status_code == 201
    data = response.json()
    with TestingSessionLocal() as db:
        item = db.query(Item).filter(Item.name == [2]).first()
        assert item is not None
        assert item.name == [3]

Drag options to blanks, or click blank then click option'

A{'name': 'Test Item'}

B"Test Item"

C'Test Item'

D{'name': 'Another Item'}

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong data type for JSON payload.

Mismatching quotes in string literals.

Not querying the database correctly.

The test posts JSON with the item name, then queries the database for the same name as a string. The JSON uses a dictionary, and the query uses string literals.