Add support for service blocking

[raman325]

I have created several functions in pyscript that make calls to other services. I could use task.wait_until to block execution until the service is finished running, but it seems more convenient to be able to specify that in the service call directly. As such, I have added support for the blocking and limit parameters which will give users more control over the service call behavior.

I am unsure how to test this - I'd be happy to add tests if you have some ideas on the best way to do that.

[raman325]

I figured out how to test at least the changes in pyscript.function. Please hold off on merging while I add tests.

[craigbarratt]

This looks good - I don't have any suggested changes.

For testing, it would be great if you could add some. These are quite tricky though because you can't actually wait any noticeable amount of time, and there are race conditions. Here's what I'd recommend.

For blocking, the test could use these steps:

• copy the initialization where we handshake the hass started event to make sure everything is up and running
• in the pyscript startup function:
  • set pyscript.var1 = 1
  • make a service call to another pyscript function with blocking=True
  • that second pyscript function sets pyscript.var1 = 2
  • immediately after the service call returns, send pyscript.var1 back through the pyscript.done queue
  • the test code asserts that pyscript.var1 = 2
  • repeat the test for other type of service call (eg: both service.call() and pyscript.func())

I don't see a good way to test blocking=False since there are race conditions.

For limit, do a test similar to the above, but the second function just does a long task.delay() and the caller uses limit = 1e-6 and blocking=True. Just the fact the service call returns means limit is working.

[raman325]

Let me know what you think of the tests I added. We don't actually have to test that the function blocks since that is Home Assistant's job, we just need to make sure that the appropriate params get passed to async_call

[craigbarratt]

Do you think this is ready now? I'm happy to try adding the couple of tests I proposed. Your tests look good too.

[raman325]

Yes I feel good about this PR now, but if you would like to add some tests that actually test the blocking please do. I think I understand what you are proposing but you would probably be able to add the tests faster

[craigbarratt]

Great - thanks. Merged.

[craigbarratt]

I added some additional tests in a25063d.

[raman325]

Great, thank you!