{"id":4569,"date":"2022-10-17T08:00:52","date_gmt":"2022-10-17T07:00:52","guid":{"rendered":"https:\/\/www.diogonunes.com\/blog\/?p=4569"},"modified":"2022-10-28T09:59:46","modified_gmt":"2022-10-28T08:59:46","slug":"lean-contract-testing-with-chakram","status":"publish","type":"post","link":"https:\/\/www.diogonunes.com\/blog\/lean-contract-testing-with-chakram\/","title":{"rendered":"Lean contract testing with Chakram"},"content":{"rendered":"
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Photo by Cytonn Photography<\/a> on Unsplash<\/a>
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\ud83c\udfc6 This post was featured in Software Testing Weekly #142<\/a> and CodingJab #111<\/a><\/p>\n<\/blockquote>\n

During my career, every time my team has to rely on a 3rd-party API, there comes the day where that API fails. Maybe it is down but usually they released a breaking change that breaks the previous contract. Our team does not notice it, but the client\/user does and then we look bad.<\/p>\n

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Even though there was a problem in the backstage (provider API), our system is the one that faces the users. So there’s a problem, we are the ones who get hit with the \ud83c\udf45 rotten vegetables, thrown by the angry audience.<\/p>\n

Test closer to the problem<\/h3>\n

There’s multiple ways to reduce the risk of this ever happening.<\/p>\n

You can test flows of your system, so that you can notice when something becomes broken. This approach will tell you there’s a problem, but it’s unlikely it will tell you where. That’s the problem of “Testing Through the UI”<\/em>, instead of “Testing the API”<\/em>. If you want to read more about it, check Say TaTTa to your TuTTu<\/a> by Mark Winteringham.<\/p>\n

Since we want to detect a broken API, let’s test as close as possible to that API. That’s the interface or contract of the API. If you are curious, check Integration tests are a scam<\/a> by J. B. Rainsberger.<\/p>\n

We know how to call the API and we know what we expect to get in return, both in terms of structure<\/strong> and data<\/strong>. We want a test to fail when:<\/p>\n