How to Test @ InjectReactive() of Vue-Property-Decorator with Vue Test Utils

A comprehensive guide on how to use `@ InjectReactive()` with Vue Test Utils, including tips for providing reactive data in your tests.
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Understanding @ InjectReactive() with Vue-Property-Decorator

When working with Vue and the Vue-Property-Decorator library, developers often utilize decorators like @ InjectReactive to manage dependency injection in their components. However, testing these components can sometimes pose challenges, especially regarding how to provide data to the injected properties.

The Problem at Hand

In this case, we have a parent component Preferences that provides a reactive property serviceLevels, and a child component CarrierFilters that requires this property through @ InjectReactive. The issue arises during testing with Vue Test Utils, where an error is encountered indicating that the injection key _reactiveInject_ cannot be found.

Parent Component

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Child Component

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The Testing Dilemma

In the testing setup, the developer attempts to provide the reactive data in the following manner:

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Despite the efforts, they are met with a console error stating that the injection _reactiveInject_ was not found. This can be frustrating and confusing for developers who expect @ InjectReactive to work similarly to @ Inject.

The Solution: Properly Providing Reactive Injected Properties

To overcome this issue, it is important to understand that reactive properties need to be provided differently when testing. Specifically, all reactive properties should be encapsulated within the _reactiveInject_ key. Here’s how you can achieve this:

Step-by-Step Guide

Wrap Reactive Properties: When mounting your component in tests, ensure that you are providing all reactive properties inside the _reactiveInject_ object.

Update Your Mounting Code: Modify the provide option in your testing code like this:

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Run Your Tests Again: After making this change, run your tests. The error regarding the missing _reactiveInject_ should now be resolved, and the child component should be able to access the provided serviceLevels.

Conclusion

When testing Vue components that utilize @ InjectReactive, understanding the nuances of how to provide reactive data is crucial. Always remember to enclose your reactive properties within the _reactiveInject_ switch, as shown. This small adjustment can significantly ease the testing process and help you achieve the desired functionality in your components.

In summary, by following this approach, you should be able to seamlessly integrate reactive data into your Vue tests, leading to more robust and reliable applications.