Top 6 Tips for Working with Lightning Testing Service

Lightning Testing Service (LTS) is a set of tools designed to help you test the JavaScript in your Lightning Components. Even though it is still in pilot, if you are developing Lightning Components, I highly suggest you take the time to check it out. Using this tool will be very important in ensuring that your components behave as expected.

As far as what LTS contains and how you use it, I suggest you refer to this Getting Started With Lightning Testing Service post by Christophe Coenraets from the Developer Relations Group. He does a great job of getting you started building your first test suite.

In this post, I will just highlight the super important things you need to know about working with LTS:

1. You do not have to install SalesforceDX to work with LTS, but I really think you are missing the point if you try to. SalesforceDX not only makes it much easier for you to work with LTS, but the thinking behind using SalesforceDX is very similar to why you need JavaScript testing. Testing your Aura methods with unit tests and manually testing your components is not enough to ensure that your lightning components are behaving correctly. It also does nothing to ensure that they will continue to behave correctly as you introduce more code.
2. Wrappers are ONLY provided for Jasmine and Mocha. If you want to use another testing framework, you will have to build your own wrapper, which will probably take you about a day to do. But, Jasmine is very easy to use and unless you are already using another JavaScript testing framework, I suggest you stick to Jasmine.
3. You do not install or use LTS in production. Seriously! This is just for development environments and even better it is for scratch orgs that you create using SalesforceDX.
4. LTS includes sample code to get you started. This includes not only the Jasmine and Mocha wrappers, but a Lightning App called JasmineTests.app that you can use to jump start your testing. Just follow the instructions in Christophe’s blog post and you should be up an running in no time.
5. You do have to create and upload Static Resources that contain the JavaScript code for your Jasmine test suites. But, SalesforceDX provides commands for doing this easily so it is not quite such a cumbersome process to replace code as you are doing your development.
6. This is the most important tip: Do not use LTS to test your server code. Keep your client and server-side testing separate. When calling Apex server methods that insert records with LTS, the data that is created is NOT rolled back. You have to be responsible for rolling back the data yourself. You can still mock the server call and an example of this is provided in Christophe’s blog post as Scenario #6. This is the recommended and best way for you to test the server code in your lightning Components. You can still create (and you actually still need to) regular unit tests to test that your Aura methods work as expected.

Ok, that’s it.

Hope it helps and good luck in your journey towards becoming an AWESOME Lightning Developer using Lightning Testing Service.