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Front End Masters: Testing Practices and Principles

Overall​

  • Overall, it was a good course but I have seen a bunch of this from working already. It was a good overview.
  • This testing trophy is interesting:

../assets/testing-trophy.png" - fix asset path

  • the higher you go, the more expensive it is to run the test and the slower they run.

Section 1: Unit Tests​

  • one cool snippet is for unit tests when trying to test multiple cases. In this example, we are checking whether isPasswordAllowed is returning the correct value for multiple good and bad passwords:
describe('isPasswordAllowed only allows some passwords', () => {
  const badPasswords = [123, 'fffffff', '1234567']
  const goodPasswords = ['123.abc', '123abc.', 'abc123.']

  badPasswords.forEach(badPassword => {
    test(`isPasswordAllowed rejects ${badPassword}`, () => {
      expect(isPasswordAllowed(badPassword)).toBe(false)
    })
  })

  goodPasswords.forEach(goodPassword => {
    test(`isPasswordAllowed accepts ${goodPassword}`, () => {
      expect(isPasswordAllowed(goodPassword)).toBe(true)
    })
  })
})
  • Dodds recommends not necessarily getting 100% code coverage. At a certain point, you're changing source code to fit your tests.
  • Code coverage also doesn't consider how necessary a particular part of the code is...not all code is of equal importance.

Section 2: Mocks​

  • CM: the first part of the mocks section I've done before. I get how he "monkey patches" the function but I never did that or learned that...I started at how it looks like it should be done.
  • you could also create a __mocks__ directory and put the mock in there. Then you can just import it like any other module.

Section 3: Testing Practices​