Скачать или смотреть Understanding Why wrapper.find Fails in Jest Tests for Connected Components

Learn how to resolve issues with `wrapper.find` in Jest tests when using connected components in React Redux by importing components correctly.
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This video is based on the question https://stackoverflow.com/q/62442589/ asked by the user 'Antriksha Somani' ( https://stackoverflow.com/u/9358324/ ) and on the answer https://stackoverflow.com/a/62443811/ provided by the user 'Red Baron' ( https://stackoverflow.com/u/10795348/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Troubleshooting Jest Tests for React-Redux Connected Components

Testing components in React with Jest and Enzyme can sometimes be tricky, especially when components are wrapped in higher-order components (HOCs) like Redux's connect. If you're experiencing issues with the wrapper.find method, you're not alone. This guide dives into a common pitfall developers face when testing connected components, and how to solve it efficiently.

The Problem

In one particular test case, a developer noticed that their assertion to find a Trade component using Enzyme’s wrapper.find method was failing. Here’s a snippet of the code they were working with:

[[See Video to Reveal this Text or Code Snippet]]

When logging the current state of wrapper, the output was:

[[See Video to Reveal this Text or Code Snippet]]

The key takeaway from this output is that the component being tested isn't Trade directly; it's a connected version of Trade—hence the name Connect(Trade). This presents a challenge when trying to find Trade in the test, as it's not instantiated as it would be outside of a Redux context.

The Solution

Import the Component Outside of connect

The primary solution to this issue is to ensure that the Trade component is imported and used correctly. The Trade component should be defined outside of the Redux connect wrapper so that Jest can recognize it during the test.

Step-by-Step Fix

Define the Component: Make sure your component is exported properly. Here’s an example of how to set this up:

[[See Video to Reveal this Text or Code Snippet]]

Connect the Component: You can then connect the Trade component to Redux separately:

[[See Video to Reveal this Text or Code Snippet]]

Import in Your Test File: In your test file, import Trade directly to be able to use it in your assertions:

[[See Video to Reveal this Text or Code Snippet]]

Update Your Test: Ensure you are referring to the Trade component properly in your assertions.

Conclusion

By following these steps, you should be able to successfully identify and assert the presence of the Trade component in your Jest tests. Remember, when working with connected components, always import the original component outside of the connect context to make it easier to reference in your tests.

By addressing this testing hurdle, you’ll streamline your testing process and minimize confusion when navigating connected components in React Redux applications. Happy testing!