[feat] Way to check that there are zero waiting timers

[thejohnfreeman]

It'd be nice to have a method that can tell me if there are any waiting timers, so I can assert in tests that every timer has run or been cleaned up.

Reading the code, I see that clocks have a timers property which is an object mapping timer IDs to timers. I could check that that object has zero own properties, but it is not a documented part of the public API, so I'm at risk of breaking changes.

Another option would have runAll return the number of timers it ran, so that I could assert at the end of my tests that number is zero, but it is returning clock.now in the current version. That does not appear to be a documented part of the API, but changing it risks breaking users mistakenly depending on it.

What do you think?

[SimenB]

Dupe of #163.

We need this in Jest as well, FWIW.

[fatso83]

I think we would love a PR for such a feature 😉 Check out #163 for some background on what we need.

[thejohnfreeman]

I'll work on it this weekend. Just some docs and test(s) on the return value of .uninstall?

[SimenB]

We shouldn't have to uninstall to get the count. I might want to check e.g. remaining timers per run of my function or something

[benjamingr]

We shouldn't have to uninstall to get the count. I might want to check e.g. remaining timers per run of my function or something

Did anyone actually ever ask for that for a real use case? Not saying that it's not important - only that I haven't seen a request.

[SimenB]

Facebook has a test for debouncing or something like that, which checks how many timers are scheduled after calling a function. Not sure if the uninstall would be enough in that case, actually