Unit Testing

recap

Goals / why write tests

• find bugs?
• prevent bugs
• help to understand code
• keep jr. devs busy :)

What is unit?

• function? class? module?
• entire app?
• entire app + environment?

Terms

• mocks / stubs
• code coverage

• unclear scope
• no assertions
• fail randomly
• hardly readable
• adapt to the code
• excessive mocks

• it's clear what unit is
• one assertion*
• fail only when something is broken
• look like documentation
• shape the code
• no mocks

React Testing

let unit = 'function';

1. extract complex pieces of logic
2. test them

let unit = 'component';

1. Create a <Component with='props' />
2. Run asserts on it...

let unit = 'story';

backstopjs + storybook = a match made in heaven

let unit = 'application';

Out of today's scope.

When needed - take a look at cypress.io

https://youtu.be/gK5I7bq72Fw?t=3814 - react2020q1