| ▲ | WorldMaker 18 hours ago |
| If your JS tests are dependent on specifics in JavaScriptCore or V8 are you really writing unit tests? If you want the extra confidence, run it with bun:test and node:test to cover JSC and V8. But JS should be JS and for unit tests feeling a need to test on multiple JS engines is a possible code smell. |
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| ▲ | MrJohz 14 hours ago | parent | next [-] |
| Neither of the test libraries are specific to unit tests, so I don't quite understand that comment. That said, there are a lot more issues than just the differences between JSC and V8 - the Bun and NodeJS runtimes, while theoretically exposing the same modules, have a lot of practical differences that are visible in userland code, such as different exceptions, different orderings of queue events, etc. I imagine quite a lot of more complex code depends in some way on platform behaviours like these. |
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| ▲ | jitl 16 hours ago | parent | prev [-] |
| Tests are about catching bugs, not playing no-true-Scotsman about what is or is not “unit test-y enough” to be a valid test. |
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| ▲ | WorldMaker 15 hours ago | parent [-] | | If you have a bug that acts different on JSC than V8 or vice versa that's not necessarily a bug in your code. It maybe implies that your code is doing something wrong and should take a more web platform "standard" approach. It generally implies that you are relying on browser specifics that you'd likely be better off testing directly in those browsers in functional/integration tests. The point about saying "those aren't unit tests" is that it is a "wrong tool for the wrong job" problem. Of course I don't expect Node or Bun to act like any specific browser. The things I want to test in Node or Bun are "universals" that should work in any JS environment, no matter what. If I need to catch V8-specific bugs or JSC-specific bugs, I want to use a smarter integration testing tool like Cypress or Playwright for that, not slow down my unit test suite trying to make a unit test harness pretend to be browsers. | | |
| ▲ | jitl 8 hours ago | parent [-] | | I misinterpreted what you mean –– I thought what you meant was "even if your software runs in NodeJS, you can test in Bun, and mock out all the Node modules since otherwise it's not a unit test". Agree that for testing code intended to run in a browser, either of Node or Bun is fine. |
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