The description of TDD could use some elaboration

[cofauver]

I propose adding the following to the README

Test Driven Development

What is a test?
A test is a piece of code designed and built to check the functionality of your code and provide descriptive, custom error messages if the code does not work and success messages if the code does work.

Software developers use tests as the specs for their code. They'll build the tests and then build the server (or client-side application) to satisfy those tests. This process is called Test Driven Development (or TDD).

The process

1. People working on the project will break down the problem into bite sized chunks and figure out what values and states of the code can be tested. Imagine something like: "At this state of the code the array should have 3 elements."
2. Developers write tests that will only pass if the app is working properly. They make sure the messages that these tests send are descriptive and helpful for specifying how the app will work.
3. The developers write a program to satisfy the tests one by one.
4. In order to refine their solutions, developers will fill in gaps in their tests or extend the test suite to include tests for new features to build. They'll repeat the process until a project is complete.