• Protect against regressions
• Encourages you think and write code in a more modular and loosely coupled way
• Gives you confidence when adding new features or while refactoring
• Takes more time upfront but makes maintaining a clean codebase better down the road

What are unit tests?

• Break your code into pieces, usually functions and modules, and then testing those individual pieces
• Make sure that when a function accepts an argument that it returns a desired value or an error

What are integration tests?

• Make sure communications and connections between different parts of your code work
• Make a mock API request and make sure that those items are rendered on the page
• Test user interactions
• Make sure URL states are correct