When thinking about good quality software we must always have very present that tests automation is a must. There is a full list of tiers and tools that can be used to ensure that your software behaves as expected, bugs typically introduced by refactoring are prevented, and interconnected systems behave well together, as for example your code together with a Salesforce upgrade. In this post I want to focus on how to write unit tests for Lightning Components using Lightning Testing Service (LTS).