Add shared dummy Tango attribute state

[gupichon]

Description

Add shared state for dummy Tango attributes used in tests. This allows tests to initialize an attribute value before loading a configuration, and all later dummy DeviceAccess objects for the same Tango attribute share that value.

Related Issue

• Fixes Feature: shared Tango attribute state in dummy control system #239

Features/issues described there are:

• new feature: dummy Tango attributes now use a shared registry keyed by attribute name.

Changes to existing functionality

• tango.pyaml.attribute delegates value, unit, range and readback storage to a shared registry.
• attach_array() no longer relies on implicit [0.0, 1.0] initialization; tests initialize array attributes explicitly.
• pytest clears the dummy Tango registry between tests.

Testing

The following tests were added or updated:

• shared dummy Tango attribute state
• read-only attribute initialization
• indexed BPM test with explicit array initialization

Verify that your checklist complies with the project

• New and existing unit tests pass locally
• Tests were added to prove that all features/changes are effective
• The code is commented where appropriate
• Any existing features are not broken

[JeanLucPons]

On the code you write (not only on this PR) there is absolutely no comment. May be your code is clear for you but I often pain to read it. Please try to put few comments to explain a bit what the code do ! Few lines can help a lot other to understand and to maintain.
Last but not least there are lots of other priority task to do.
Thanks for understanding.

[gupichon]

I'll add comments. I actually need this to simplify the BPM evolution and tests for other developments. For example, the attach_array method will be removed since it’s no longer necessary (it simply calls attach on the backends).

Moreover, it will simplify BPM testing as you’ll be able to set them to test values in live mode. This will allow for tests on the live system that were previously impossible.

[gupichon]

By the way, I added a test for dummy-cs. It’s not mandatory, but it will help since it’s something we actually have to maintain..

[JeanLucPons]

I'll add comments. I actually need this to simplify the BPM evolution and tests for other developments. For example, the attach_array method will be removed since it’s no longer necessary (it simply calls attach on the backends).

Not on the pyaml_cs_oa side, but this should change if the Ophyd Asynch fix is deployed.

[JeanLucPons]

    def attach(self, devs: list[OASignal]) -> list[OASignal]:
        return self._attach(devs,False) # is_array=False

    def attach_array(self, devs: list[OASignal]) -> list[OASignal]:
        return self._attach(devs,True) # is_array=True

[gupichon]

Not on the pyaml_cs_oa side, but this should change if the Ophyd Asynch fix is deployed.

I forgot about this point, you're right. Anyway, it will help a lot with testing, as you can set the live part with this development.

[JeanLucPons]

Is it ready to merge ?

[gupichon]

Is it ready to merge ?

Yes, all tests are passing, and I have added a test specifically for the dummy because, ultimately, we depend on it for delivery.