Unit tests are key to producing more robust and less buggy software.

In this thread I will discuss everything about unit tests. Examples will be in Swift and XCTest framework, but the principles apply generally to all languages and test frameworks.

Thread 🧵👇 1. What is a unit test?

Unit test is a method that runs a piece of code to verify that a known, fixed input produces a known, fixed output. If the assumptions turn out to be wrong, the unit test considered failed.