Intercepting Real Data Responses with Cypress

Описание: Learn how to effectively intercept and modify real data responses in Cypress for your automated tests. This guide covers setting up intercepts, server configuration, and troubleshooting tips.
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This video is based on the question https://stackoverflow.com/q/65155934/ asked by the user 'TheTanadu' ( https://stackoverflow.com/u/5441779/ ) and on the answer https://stackoverflow.com/a/65156547/ provided by the user 'Richard Matsen' ( https://stackoverflow.com/u/4716245/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Intercepting Real Data Responses with Cypress: A Comprehensive Guide

In the world of automated testing, particularly with frameworks like Cypress, developers often face the need to intercept and manipulate data responses. This is crucial for creating a reliable testing environment that mimics real-world scenarios while enabling the testing of various states without needing to rely solely on the server. Today, we'll explore how to intercept actual server responses in Cypress, implement modifications, and troubleshoot common issues that may arise.

Understanding the Problem

Suppose you are working on a Cypress project and trying to replace real server data with custom data for testing purposes. It can get tricky, especially when dealing with issues where the modified data does not reflect as expected. A user encountered a scenario where their intercept for the URL http://localhost:3000/spoons returned an empty object in the console, despite the server reliably providing data.

Example Server Response

The user set up a simple Express server that responded with the following object:

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However, the console log just displayed an empty object when trying to manipulate the response.

The Solution: Step-by-Step Guide

Let’s break down the solution to intercept real data and ensure it returns the expected results.

1. Set Up the Server

Ensure you have a simple server ready to respond to your request. Here’s a basic setup using Express:

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2. Modify the Cypress Test

In your Cypress test, intercept the network request and modify the response. Here’s how you can do it:

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3. Ensure Proper Fetch Handling in HTML

To correctly log response data, ensure your fetch script in your HTML file resolves the promise appropriately:

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4. Cache Control

To avoid stale data responses (HTTP 304 errors), implement a cache control to your server responses:

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Conclusion

By following the steps outlined above, you can successfully intercept real data responses in your Cypress tests, allowing for enhanced testing capabilities. Remember to always check your console for logs and to ensure that your server is responding correctly to your intercept requests. This guide provides a solid foundation for manipulating server responses to suit your testing needs effectively.

Now, armed with this knowledge, you should be able to tackle your data interception challenges and streamline your automated tests with confidence!