Test improvements

Working on #403 exposed a couple of potential improvements for the tests. I’m creating this issue to align which ones should actually be done, and how the changes should be grouped into PRs.

• Reduce the usage of any in test files (#417)

  • Came up here
  • Would mean to add quite some type definitions to test files. Too much boilerplate? But types are nice, so I’m in favour of doing it.

• Remove unnecessary mocks of console.error (#420)

  • Came up here
  • I guess the mocks are in for cases like this one. Still can be removed where not used.

• Rename persistSync.test.tsx to .ts as it doesn’t contain any JSX.

• Rename persist.test.tsx to persistAsync.test.tsx to be consistent. (#416)

• Wrap tests in persist.test.tsx into a describe() block to be consistent with [persistSync.test.tsx] (#416)(https://github.com/pmndrs/zustand/blob/master/tests/persistSync.test.tsx)

  • or should this be done with all test files?

• persist.test.tsx: Make sure that onRehydrateStorage was not called with an error (#423)

  • I noticed that the tests will not fail on errors occurring during state initialisation as the error is only passed to onRehydrateStorage. Therefore each test needs to verify that onRehydrateStorage was called with undefined.
  • I already added this check to persistSync.test.tsx (see example)

• persist tests: Use jest.fn() to mock onRehydrateStorage instead of hand-crafting a spy (#423)

  • See here as example
  • No big deal, but my guess is that it would simplify the code, and make it more fail-safe

• Add this test to the persist.test.tsx as well. (#430)

• Add some structure to basic.test.tsx (#424)

  • Right now it’s 800 lines of it() calls 😅
  • One way to add a bit of structure would be to have each subscribe and type-related tests be grouped under a separate describe() call within the same file.
  • … or break up the file? Would need feedback on that one.

• perstist*.test.tsx: Expand it(‘can persist state’) by verifying that the persisted state is actually written to the storage (#431)

  • One of the more important scenarios, right?

• split tests for subscribe() into multiple it() blocks (#427)

• replace callbacks with spies for subscribe() tests (#429)

• persistAsync.test.tsx: Move component Counter to top of file

  • Tried it, doesn’t seem to be worth it. Will skip.

• Address inconsistency of arguments for onRehydrateStorage between sync and async (#437)

  • Follow-up of this

• Follow up on #431 (#436)

  • Implement also for async version.

• Add tests for outer onRehydrateStorage callback`

  • At the moment the tests only test the function returned by onRehydrateStorage which is called after rehydration, not the one that’s called before rehydration.

I guess that all of those deserve separate PRs. So I’d just need to know which ones you want to be done, then I’d get going.

[barbogast]

Oh, right, the ticket is still open.

It can be closed as far as I’m concerned. One item is still open, but I’m doubtful that it’s important enough and worth the effort.

Closing…

[dai-shi]

I’m fine. Having new ideas after some work is not surprising. Thanks for your contributions.