notes.md

Test Driven Development

1. Make It Fail
2. Make It Pass
3. Refactor

Workflow

0. Write test write a test to prove the next small piece of functionality is missing or wrong

--> Run all the tests All the tests should fail

1. Write Code write the simplest production code to fix test

--> Run all the tests All the tests should pass

YOU NOW HAVE CODE THAT WORKS

2.Refactor Incremental refactoring the code untill its acceptable

*** YOU NOW HAVE CODE YOU LIKE***

Practical

pre reqs

• jest for testing
  • install globally npm install jest --global
• wallaby for test running
  • install vscode plugin
  • get the Web App

1. before writing index.js, create index.spec.js
2. write first test as describe block the first describe block is usualy the name of a feature or the entry point to the application

• the entry point is the point where execution begins
• Unit test == Unit of work
• Unit of work has entry point and exit point
• entry point is where function is invoked
  • use the name of the function
• exit point
  • return value
  • state change
  • output file