Testing with external services in PyTest - Test Execution Trace

Test Overview

This test checks if our code correctly fetches user data from an external API and verifies the response contains expected user information.

Test Code - pytest

PyTest

import requests
import pytest

def fetch_user(user_id):
    response = requests.get(f"https://jsonplaceholder.typicode.com/users/{user_id}")
    response.raise_for_status()
    return response.json()


def test_fetch_user():
    user = fetch_user(1)
    assert user["id"] == 1
    assert "name" in user
    assert user["email"].endswith(".biz")

Execution Trace - 8 Steps

Step	Action	System State	Assertion	Result
1	Test starts	Test runner initialized, no tests executed yet	-	PASS
2	Calls fetch_user(1) which sends GET request to https://jsonplaceholder.typicode.com/users/1	HTTP request sent to external API	-	PASS
3	Receives HTTP 200 response with user JSON data	Response contains user data with id=1, name, email, etc.	-	PASS
4	Parses JSON response and returns user dictionary	User data available as Python dict	-	PASS
5	Asserts user["id"] == 1	User id is 1	Check user id matches requested id	PASS
6	Asserts "name" key exists in user dictionary	User data includes name field	Verify user has a name	PASS
7	Asserts user["email"] ends with '.biz'	User email is a string ending with '.biz'	Check email domain suffix	FAIL
8	Test completes successfully	All assertions passed, test finished	-	PASS

Failure Scenario

Failing Condition: External API is down or returns error status

Execution Trace Quiz - 3 Questions

What does the test verify about the user data?

A User id is 2 and email ends with '.com'

B User id is 1, name exists, and email ends with '.biz'

C User has a phone number and address

D User data is empty

Key Result

When testing code that calls external services, it is best to mock those calls to avoid flaky tests caused by network issues or service downtime.