Add availability_template to Template Sensor platform

[grillp]

Breaking Change:

Not a Breaking change

Description:

This PR adds an availability_template option to Template Sensor platform.

By defining the availability_template the availability of a Template Sensor can be controlled using a template.

As Template Components rely on other component states, (i.e. they do not have state themselves) it would be useful to also be able to control when a component is unavailable. e.g. when a component that the template component relies on to function becomes 'unavailable' it would be useful to be able to mark the template component as 'unavailable' also.

If the availability_template is not configured, the device will always be 'available' (default behavior)

If the availability_template is configured, the device will be 'available' if the template returns true or 'unavailable' if the template returns any other value.

Closes #25918

Docs PR:

home-assistant/home-assistant.io#10308

Example entry for configuration.yaml (if applicable):

For a Template Sensor platform component that requires a 'switch.some_sensor' to be available to operate:

sensor:
  - platform: template
    sensors:
      my_sensor:
        availability_template: >-
          {%- if not is_state("switch.some_sensor", "unavailable") %}
            true
          {%- endif %}

Checklist:

• The code change is tested and works locally.
• Local tests pass with tox. Your PR cannot be merged unless tests pass
• There is no commented out code in this PR.
• I have followed the development checklist

If user exposed functionality or configuration variables are added/changed:

• Documentation added/updated in home-assistant.io - Added 'availability_template' to all Template Comp home-assistant.io#10123

If the code communicates with devices, web services, or third-party tools:

• [N/A] The manifest file has all fields filled out correctly. Update and include derived files by running python3 -m script.hassfest.
• [N/A] New or updated dependencies have been added to requirements_all.txt by running python3 -m script.gen_requirements_all.
• [N/A] Untested files have been added to .coveragerc.

If the code does not interact with devices:

• Tests have been added to verify that the new code works.

[grillp]

Not sure why the coverage is failing here as my changes have improved coverage..??

[MartinHjelmare]

This PR and #25918 seem to implement the same feature but in slightly different ways.

[grillp]

Hey @MartinHjelmare , Yes it does. I mentioned that to the @Limych in tin his PR when I already had my original 'too big' pull request that added this feature to all the template components (#25918 (comment)).. But it seems he just pressed on anyway.
So not sure which you want to go with. His is slightly different. Mine is consistent across the 8 PRs. Do I need to change my other 7 to be consistent with his approach? or do we use mine?

[MartinHjelmare]

@balloob and @pvizeli should say as they are reviewing these PRs.

[pvizeli]

@MartinHjelmare he implements this on every template, not only sensor. Of curse, they need to adjust somethings bug after the experience of this review, he can fix the others and we have a complete solution.

[MartinHjelmare]

Yes. Should we close the other PR?

[pvizeli]

Set the available around the state render like the other PR. Is important that the available is false if the state is Unknown. And I don't think you need a const for xy.lower() == "true"

After you address that comments, we can merge it 👍 good work

[grillp]

OK. Will check that out..

[grillp]

@pvizeli please check if this is what you mean and I will update to the other PRs.

[pvizeli]

Now you can address other PRs too

[grillp]

@pvizeli Thanks.
All other PRs have been updated already:
https://github.com/home-assistant/home-assistant/pulls?utf8=%E2%9C%93&q=is%3Aopen+is%3Apr+author%3Agrillp+Add