Improve testing for model

[antonmedv]

For example, I'd like to test my https://fx.wtf app. But right now testea only tests final output (which is 0 for fx).

I'd like to be able to send keystrokes and check intermediate results (same with -update model).

[caarlos0]

It's possible to do that with waitfor: https://github.com/charmbracelet/x/blob/main/exp/teatest/app_test.go#L64

[antonmedv]

It is, but not as easy as snapshotting of final result with RequireEqualOutput.

Will be cool to have similar snapshots for the intermediate model state.

[caarlos0]

unfortunately its not as easy while the app is running, as you might get an "old" "snapshot", of the output, that's why there's the WaitFor, in which you can keep checking the output for X time every Y interval.

[antonmedv]

It is understandable. But for my app after key press is done it will "freeze". So "snapshot" is possible.

[caarlos0]

unfortunately, no, it isn't, as we can't guaranteed that the event was already processed after you send it, so you'll likely end up with a bunch of time.Sleep to try to synchronize the work.

you could do something like:

var snapshot []byte
teatest.WaitFor(t, tm.Output(), func(out []byte) bool {
  snapshot = out
  return true
}, teatest.WithDuration(time.Second), teatest.WithCheckInterval(time.Millisecond*100))

// verify snapshot

but I don't see how that's better than doing it inside WaitFor.

---

Forgot to add earlier: as for the model throughout the run, you have it when you start the test, so you can test it directly.

[caarlos0]

Oh, you can also read tm.Output() at any given time.

[antonmedv]

Oh, you can also read tm.Output() at any given time.

For some reason it is nil. But the snapshot technic works.