Read aperture properly rather than private method

[DominicOram]

See DiamondLightSource/dodal#782

Requires dodal version DiamondLightSource/dodal#789

To test:

• Confirm test passes

[DiamondJoseph]

selected_aperture is the sole HintedSignal of aperture_scatterguard, you should be able to just aperture_scatterguard.read()?

[DominicOram]

I'm not sure I see the advantage of this as it's more verbose and now makes the test depend on the fact the signal is hinted but don't care so much so have changed it. Are you suggesting it because read() is the more externally facing API over get_value()?

[DiamondJoseph]

Looking at the change to the test I think I was just wrong? I thought that
selected_aperture.read() == ApertureValue.SMALL

And then we could ensure that the selected_aperture was always readable and always gave the ApertureValue as its output.

[DominicOram]

Yh, I think even reading the one signal it will still return a dict with the name and value.

But the test shouldn't care if it's readable or hinted. The test is "does doing this plan change the aperture in the expected way". We have other tests that are "can I read the selected aperture in the way I expect" like

mx-bluesky/tests/unit_tests/hyperion/experiment_plans/test_flyscan_xray_centre_plan.py

Line 301 in 1dc26a5

"aperture_scatterguard-selected_aperture": ApertureValue.SMALL,

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 77.61%. Comparing base (1928954) to head (92401d8).
Report is 3849 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff             @@
##             main     #506       +/-   ##
===========================================
+ Coverage   57.08%   77.61%   +20.53%     
===========================================
  Files          28       89       +61     
  Lines        3199     6704     +3505     
===========================================
+ Hits         1826     5203     +3377     
- Misses       1373     1501      +128     

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[DiamondJoseph]

Sorry re: confusion with the scatterguard read: I think it was neater before my previously requested changes but either way the change is more correct than before and either is compatible with the patched version of dodal