pytest is a Python testing framework for writing and running automated tests. It supports short feedback cycles by checking small pieces of functionality as code is built, including generated code that still requires verification. section 2.4
A practical pytest workflow starts with small questions and expands toward deeper behavior:
- Check whether a file can be read and whether it contains the expected number of records. section 2.4
- Test individual record types and parsing behavior after the basic file-reading test works. section 2.4
- Exercise an API endpoint through FastAPI's TestClient, then assert its HTTP status and JSON response. section 4.3.1
- Deliberately change the endpoint, request type, expected status, or expected JSON to confirm that the test can fail. section 4.3.1
Testing a files endpoint
Create a TestClient for the application, call GET /files, assert status code 200, and compare the returned JSON with the expected file list. section 4.3.1
Listing 4.4 Testing our first endpoint
from fastapi import FastAPI #1
from fastapi.testclient import TestClient #1
from app.main import app #1
client = TestClient(app) #2
def test_read_files(): #3
response = client.get("/files") #4
assert response.status_code == 200 #5
assert response.json() == #5
➥[{"file": "File_1"}, {"file": "File_2"}] #5
Use the endpoint test listing as a compact reference for importing TestClient, creating a client, making a request, and asserting the response. section 4.3.1
