Скачать или смотреть How to Mock Getters from Vuex Store in Vue Test Utils

Learn how to effectively mock only specific getters in your Vuex store while testing your Vue.js applications using Vue Test Utils.
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This video is based on the question https://stackoverflow.com/q/68571498/ asked by the user 'Amir Choubani' ( https://stackoverflow.com/u/6717287/ ) and on the answer https://stackoverflow.com/a/68576649/ provided by the user 'Eduardo' ( https://stackoverflow.com/u/15004299/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Mocking Just Part of Getters When Importing the Global Store

When you're working on unit tests for Vue.js applications that use Vuex (the state management library for Vue), you may run into situations where you want to mock just a specific getter from the global Vuex store, leaving the rest of the store intact. This can be a bit tricky but is entirely possible and can save you a lot of time and effort in your tests.

In this guide, we’ll break down how to mock a single getter in the Vuex store correctly while ensuring that your tests reflect the conditions you wish to simulate.

The Problem at Hand

Imagine you have a Vue component that relies on a Vuex getter, specifically isLoggedIn. By default, this getter returns false, but for your particular test case, you want to simulate a logged-in user by having this getter return true.

Here’s the attempted code that shows your initial approach:

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

Why the Initial Approach Fails

The code above fails because you're trying to utilize both the global store and the local mocks simultaneously, which can lead to conflicts. The global store's value is being prioritized over the mocked one.

The Solution

A simpler and more effective way to mock a specific getter is to bypass the use of the global store entirely when mounting your component for the test. Instead, just define the mocks property directly. Here’s how you can achieve it:

Step-by-step Implementation

Remove Global Store Initialization: Don’t create a store instance for this test.

Use the Mocks Property: Set up your mocks to directly use the logged-in state you wish to simulate.

Here’s the streamlined code:

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

Explanation of the Code:

localVue: Create a local version of Vue to avoid polluting the global Vue instance.

router: Include your Vue Router if your component relies on routing.

mocks: Define the $store with a getters property, where isLoggedIn will return true, simulating an authenticated state.

Benefits of This Approach

Simplicity: The approach is more straightforward and minimizes the complexity involved in the test setup.

Focused Testing: Only the part of the store that you need is mocked, which can lead to cleaner and more focused tests.

Fewer Dependencies: You eliminate unnecessary dependencies on the global store when you’re just trying to test a specific piece of functionality.

Conclusion

Mocking part of the Vuex store, specifically a getter, can greatly enhance the reliability and specificity of your tests. This solution allows you to simulate different states of your application without the overhead of setting up a full store instance. By focusing only on what you need, you not only make your tests easier to write and understand but also improve their maintainability.

Happy testing with Vue and Vuex! If you have any further questions or need additional examples, feel free to leave a comment below.