199 test helpers for assering value reading and configuration

[Relm-Arrowny]

This is to fix #199 and possibly #206

Acceptance Criteria

• Functions in ophyd-async:
• assert_reading
• assert_configuration
• assert_value
• assert_emitted
• Tests provided
• Docs provided where appropriate
• Issues raised in dodal to replace verefy() and any other old functions that can be superseded

For #206 Need to document 2 ways:

• Exercise the device directly, i.e. call device.read() and inspect the output. Should use helpers made in Test helpers for assering value, reading and configuration #199
• This is already convered in test_sensor_reading_shows_value so I only changed it to use helpers made here.
• Run a plan in the RunEngine and examine the docs. Use a pattern like:
• Added test_sensor_in_plan in demo.py together with changes in the documentation.

[coretl]

Looks like this is on the right track, thanks!

[callumforrester]

You can import DocumentType from event model

Suggested change

	def assert_emitted(docs: Dict[str, list], **numbers: int):
	def assert_emitted(docs: DocumentType, **numbers: int):

[coretl]

Although docs is a dict of document name to list of document instances, so I think that should be:

Suggested change

	def assert_emitted(docs: Dict[str, list], **numbers: int):
	def assert_emitted(docs: Dict[str, list[DocumentType]], **numbers: int):

Except DocumentType is actually the types, which is not what we want, we would quite like a similar Document union in event model...

[coretl]

so in the absence of that it's probably as correct as it could be...

[coretl]

Please could you also add to the "writing tests for devices" doc the information on how to use assert_emitted from #206

[Relm-Arrowny]

I will deal with #206 the conflicts and all the changes once the main branch is stable, atm the doc will not build correctly.

[Relm-Arrowny]

I think I got everything, but please have a quick check if it all make sense and I have covered everything.

[callumforrester]

Docs look good, only a couple of formatting points

[callumforrester]

LGTM, thanks!

[coretl]

Sorry, one last thing