Unit Testing with Jest

The content that belongs to this page is related to specifics of unit testing Angular components with Jest. Some of the solutions can be applied in development itself. 

Are you a developer? Do you incorporate writing unit tests when developing applications? Is it done at all? 

I believe unit tests should be a crucial part of development, because they are helpful in determining the pitfalls in code and models, thus making the code refactoring easier. Unit testing on a daily basis creates more space for upgrading the application and preventing future problems. Instead of refactoring the entire application all at once, you can use the power of unit tests and do it gradually. Ideally, it would be done by a developer who is writing the application logic.

Continue reading through examples to find out more. 👇

 

 Errors that every Angular developer has encountered:

1. NullInjectorError 

 When you have the NullInjector error complaining about the missing provider, you have to import the module that is actually missing. For example:

Problem: 

NullInjectorError: No Provider for Store

Solution:

imports: [

    NGXSModule.forRoot([])

]

When it comes to this type of error, you can possibly get it while building the app or while running the tests. In both cases, the solution is to add the missing provider to the import statement of the module.