Section 4: Writing Good Tests

What to & Not to Test

• What should & shouldn’t be tested
• Good tests are short & concise

key points

• What should & shouldn’t be tested
  • Only test your code
  • don't test third-party code
  • don’t test what you cannot change

Example, fetch() API

• Don't test if it works as intended
• Don't test your server-side code implicitly via your client-side code
• Write separate tests for your backend code instead

Do Test your client-side reaction to different response & errors.

 

Writing Good Tests

1. AAA - Arrange - Act - Assert

 

2. 1 - Only test one thing

• For this, if function includes many code inside, separate it

3. focus - focus on the essence of a test when arranging

• Do not overuse meaningless cases. e.g. below. two numbers are enough for testing.

4. < - keep your number of assertions(”expect”) low

• avoid too many expects in a single it!

Only Test One Thing

What is one thing?

: means One feature! e.g. validate input OR transform it