Photo by Dmitriy Demidov on Unsplash
Code Smell 272 - API Chain
Streamline Your API Tests: Less is More
TL;DR: Use primitive steps to verify API behavior instead of direct requests.
Problems
- Unnecessary API calls
- Slow test performance
- Overcomplicated validations
- Fragile tests
- Slow feedback loops
- Maintainability
- Misleading test results
Solutions
- Test primitive outcomes
- Validate responses directly
- Avoid extra API steps
- Simplify test logic
Context
When you test an API, you might fall into the trap of using multiple API requests to verify a single operation.
Making a POST and immediately making a GET to check the existence of the resource with the payload is a straightforward solution.
This pattern adds complexity and makes your tests slower.
Also if your GET operation breaks, you will have many tests failing not relating to the test GET operation.
The epitome of testing is a single broken test for a wrong behavior.
Instead of verifying resource creation through a GET and inspecting the JSON response, you can focus on primitive steps.
Check if the POST succeeded by validating the status code or checking the resource's existence.
Sample Code
Wrong
Feature: Movie Management
Scenario: Create a movie and verify
When I send a POST request to "/movies" with the following data:
| title | director | year |
| Klendathu | Christopher Nolan | 2010 |
When I send a GET request to "/movies/Klendathu"
Then the response status should be 200
And the response should contain:
| title | director | year |
| Klendathu | Christopher Nolan | 2010 |
Right
Feature: Movie Management
Scenario: Create a movie and verify
When I create a movie with the following details:
| title | director | year |
| Klendathu | Christopher Nolan | 2010 |
Then the movie "Klendathu" should exist in the system
## This is a low level existance postcondition
## Without reliyng on a GET request
Detection
[X] Semi-Automatic
You can detect this smell when you see test steps that use a GET request to verify the success of a POST.
Tags
- Testing
Level
[X] Intermediate
AI Generation
AI generators often create this smell when generating API tests, defaulting to chaining requests and validating the entire resource, rather than focusing on the operation's outcome.
AI Detection
AI tools can potentially detect this smell with proper instructions.
You could train an AI to identify patterns of consecutive POST and GET requests in scenarios and suggest consolidating them into more abstract, primitive steps.
Try Them!
Remember: AI Assistants make lots of mistakes
Without Proper Instructions | With Specific Instructions |
ChatGPT | ChatGPT |
Claude | Claude |
Perplexity | Perplexity |
Copilot | Copilot |
Gemini | Gemini |
Conclusion
Focus your acceptance tests on the direct results of operations like POST.
Avoid making a GET request afterward to verify what you already know.
Relations
More Info
Disclaimer
Code Smells are my opinion.
Credits
Photo by Dmitriy Demidov on Unsplash
As a rule, software systems do not work well until they have been used, and have failed repeatedly, in real applications.
Dave Parnas
This article is part of the CodeSmell Series.