Too Long; Didn't Read
Test-driven development (TDD) is a development strategy in which you write your tests first, then your app code. Product requirements are turned into very specific test cases, and then the software is improved so that the tests pass. There are several benefits to using TDD, but here are three: testing is built right into your development cycle, not as an afterthought. It makes sure your tests are testing the right things. Every branch is covered (in theory). Every time you’re writing your tests after your code, the tests feel more meaningful.