[CI] Add new Agent for disabling or quarantining tests

[radical]

• Add support for ActiveIssue to QuarantineTools
• Add new test-disabler agent

[github-actions]

🚀 Dogfood this PR with:

⚠️ WARNING: Do not do this without first carefully reviewing the code of this PR to satisfy yourself it is safe.

curl -fsSL https://raw.githubusercontent.com/dotnet/aspire/main/eng/scripts/get-aspire-cli-pr.sh | bash -s -- 12570

Or

• Run remotely in PowerShell:

iex "& { $(irm https://raw.githubusercontent.com/dotnet/aspire/main/eng/scripts/get-aspire-cli-pr.ps1) } 12570"

[Copilot]

Pull Request Overview

This PR adds support for marking tests with [ActiveIssue] in addition to [QuarantinedTest] in the QuarantineTools utility. This allows the tool to handle both Aspire-specific test quarantining and standard xUnit test disabling workflows.

• Adds a new --mode option to switch between quarantine (default, uses QuarantinedTest) and activeissue (uses ActiveIssue) modes
• Updates the tool to handle both attribute types with appropriate namespace imports (Aspire.TestUtilities for QuarantinedTest, Xunit for ActiveIssue)
• Adds comprehensive test coverage for ActiveIssue functionality

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
tools/QuarantineTools/README.md	Updated documentation to describe the new --mode option and ActiveIssue functionality with usage examples
tools/QuarantineTools/Quarantine.cs	Added mode selection logic, constants for both attribute types, and refactored to support either attribute dynamically
tests/QuarantineTools.Tests/ActiveIssueTests.cs	New comprehensive test suite covering ActiveIssue attribute addition/removal scenarios
.github/agents/test-disabler.md	New agent instruction document for automated test disabling/quarantining via GitHub Copilot

Comments suppressed due to low confidence (3)

tools/QuarantineTools/Quarantine.cs:636

• The XML documentation comment is outdated. It should be updated to reflect that this method can now remove either [QuarantinedTest] or [ActiveIssue] attributes depending on configuration, not just [QuarantinedTest].

    /// <summary>
    /// Removes the [QuarantinedTest] attribute from a method, if present. Returns the (potentially)
    /// modified method and flags via <paramref name="removed"/> whether a change occurred.
    /// </summary>

tools/QuarantineTools/Quarantine.cs:18

• The overview comment at the top of the file should be updated to mention that the tool now supports both [QuarantinedTest] and [ActiveIssue] attributes, not just [QuarantinedTest].

// This small command-line tool helps developers quarantine or unquarantine failing/flaky xUnit tests
// across the repository's tests folder by adding or removing the [QuarantinedTest] attribute on
// test methods. It edits source files directly using Roslyn (Microsoft.CodeAnalysis) to ensure safe and
// structured modifications.

tools/QuarantineTools/Quarantine.cs:1

• The workflow description in the file header comment should be updated to describe that the tool can now add either [QuarantinedTest] or [ActiveIssue] based on the mode, and add the corresponding using directive (Aspire.TestUtilities or Xunit).

// Licensed to the .NET Foundation under one or more agreements.

[davidfowl]

I want something to investigate tests next ! 😄