Throw exception in WaitForResourceAsync and WaitForResourceHealthyAsync when resource does not exist

[Alirexaa]

Description

This pull request includes changes to the ResourceNotificationService class to add validation for resource existence and corresponding unit tests to ensure this validation works correctly. The most important changes are listed below:

Validation for resource existence:

• src/Aspire.Hosting/ApplicationModel/ResourceNotificationService.cs: Added checks to verify if a resource exists before proceeding with the WaitForResourceAsync and WaitForResourceCoreAsync methods. If the resource does not exist, an InvalidOperationException is thrown. [1] [2]

Unit tests for resource existence validation:

• tests/Aspire.Hosting.Tests/ResourceNotificationTests.cs: Added new unit tests to ensure that WaitForResourceAsync and WaitForResourceHealthyAsync methods throw an InvalidOperationException when the resource name does not exist.

Additional imports for testing:

• tests/Aspire.Hosting.Tests/ResourceNotificationTests.cs: Added necessary imports for dependency injection and health checks in the test file.

Fixes #8147

Checklist

• Is this feature complete?
  • Yes. Ready to ship.
  • No. Follow-up changes expected.
• Are you including unit tests for the changes and scenario tests if relevant?
  • Yes
  • No
• Did you add public API?
  • Yes
    • If yes, did you have an API Review for it?
      • Yes
      • No
    • Did you add <remarks /> and <code /> elements on your triple slash comments?
      • Yes
      • No
  • No
• Does the change make any security assumptions or guarantees?
  • Yes
    • If yes, have you done a threat model and had a security review?
      • Yes
      • No
  • No
• Does the change require an update in our Aspire docs?
  • Yes
    • Is this introducing a breaking change?
      • Yes
        • Link to aspire-docs issue (please use this breaking-change template):
      • No
        • Link to aspire-docs issue (please use this doc-idea template):
  • No

[Copilot]

Pull Request Overview

This PR adds resource existence validation for asynchronous wait methods in ResourceNotificationService and includes unit tests to verify that an InvalidOperationException is thrown when a non-existent resource is queried.

• Added resource existence checks before waiting in ResourceNotificationService.
• Added unit tests in ResourceNotificationTests to cover scenarios where the resource does not exist.
• Included additional using directives for dependency injection and health checks in the tests.

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
tests/Aspire.Hosting.Tests/ResourceNotificationTests.cs	Added unit tests to verify that invalid resource names trigger exceptions.
src/Aspire.Hosting/ApplicationModel/ResourceNotificationService.cs	Added validation that throws an exception if a resource does not exist.

[afscrome]

Should this only be done if DefaultWaitBehaviour == WaitBehavior.StopOnResourceUnavailable, as it is potentially possible that the resource could show up later. (Perhaps if WaitBehavior is something else, it is worth logging something to highlight that the resoruce doesn't exist, even if it doesn't blow up completely)

[mitchdenny]

On the surface this sounds reasonable. Although the thing that gives me pause is around writing test cases where you might have resources added to the model dynamically after startup. When writing a test case you might opt the wait for the resource before it even exists, but then put a timeout in place.