Replace Task.Delay with CompositionTargetHelper in RichSuggestBox tests

[Copilot]

Fixes #589

Fixes the intermittent test failures in RichSuggestBox tests by replacing Task.Delay(10) with CompositionTargetHelper.ExecuteAfterCompositionRenderingAsync() to properly wait for UI updates to complete.

PR Type

• Bugfix

What is the current behavior?

Test_RichSuggestBox_DeleteTokens, Test_RichSuggestBox_AddTokens, and other RichSuggestBox tests intermittently fail on WinUI 3 due to race conditions. The tests use await Task.Delay(10) to wait for UI updates, which isn't always sufficient for the WinUI 3 RichTextBox to complete its text changes and fire events.

What is the new behavior?

All Task.Delay(10) calls in RichSuggestBox tests have been replaced with CompositionTargetHelper.ExecuteAfterCompositionRenderingAsync(() => { }), which properly waits for the composition rendering pass to complete before assertions run.

// Before
await Task.Delay(10);   // Wait for SelectionChanged to be invoked

// After  
await CompositionTargetHelper.ExecuteAfterCompositionRenderingAsync(() => { });   // Wait for SelectionChanged to be invoked

Analysis: The intermittent failures appear to be caused by differences in the WinUI 3 platform's text control event timing compared to WinUI 2. The CompositionTargetHelper approach is already used in other tests across the toolkit (e.g., SwitchPresenterTests, ConstrainedBox, TokenizingTextBox) and provides a more reliable synchronization mechanism.

PR Checklist

• Created a feature/dev branch in your fork (vs. submitting directly from a commit on main)
• Based off latest main branch of toolkit
• Tested code with current supported SDKs
• Contains NO breaking changes

Other information

Replaced 9 occurrences of Task.Delay(10) across all RichSuggestBox tests:

• 2 in Test_RichSuggestBox_DeleteTokens
• 1 in Test_RichSuggestBox_ReplaceToken
• 3 in Test_RichSuggestBox_FormatReset
• 1 in Test_RichSuggestBox_Load
• 2 in the helper method AddTokenAsync (used by multiple tests)

Original prompt

The test Test_RichSuggestBox_DeleteTokens in components/RichSuggestBox/tests/Test_RichSuggestBox.cs is intermittently failing, particularly on WinUI 3, as discussed in issue #589. To stabilize CI and allow further investigation into the underlying cause, add the [Ignore("Intermittent failure - see https://github.com/CommunityToolkit/Windows/issues/589")] attribute to this test. Ensure only this specific test is disabled, and reference the issue in the changes.

Summary:

• Add [Ignore] attribute to Test_RichSuggestBox_DeleteTokens test.
• Provide a comment referencing the issue: RichSuggestBox Intermittent Test Failures #589.
• Other tests should remain unchanged.

This pull request was created as a result of the following prompt from Copilot chat.

The test Test_RichSuggestBox_DeleteTokens in components/RichSuggestBox/tests/Test_RichSuggestBox.cs is intermittently failing, particularly on WinUI 3, as discussed in issue #589. To stabilize CI and allow further investigation into the underlying cause, add the [Ignore("Intermittent failure - see https://github.com/CommunityToolkit/Windows/issues/589")] attribute to this test. Ensure only this specific test is disabled, and reference the issue in the changes.

Summary:

• Add [Ignore] attribute to Test_RichSuggestBox_DeleteTokens test.
• Provide a comment referencing the issue: RichSuggestBox Intermittent Test Failures #589.
• Other tests should remain unchanged.

---

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[michael-hawker]

Ironically also failed on Add Tokens too.

@copilot can you ignore that intermittent failing test as well?

[Copilot]

Ironically also failed on Add Tokens too.

@copilot can you ignore that intermittent failing test as well?

Added [Ignore] attribute to Test_RichSuggestBox_AddTokens as well in 44e61bf.

Warning

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I tried to connect to the following addresses, but was blocked by firewall rules:

• crl.godaddy.com
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• ocsp.godaddy.com
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[michael-hawker]

Hmm... now it's in CustomizeToken. I feel like there's some underlying issue with RichTextBox on Windows App SDK that is just tripping us up here, as I think we only see these fail in WinUI 3 regularly vs. WinUI 2?

@copilot instead of ignoring the tests, can you replace the Task delays across all the RichSuggestBox tests with the CompositionTargetHelper as suggested here: #589 (comment)

Please also provide any further analysis into the problem and potential solutions

[Copilot]

Hmm... now it's in CustomizeToken. I feel like there's some underlying issue with RichTextBox on Windows App SDK that is just tripping us up here, as I think we only see these fail in WinUI 3 regularl...

Replaced all Task.Delay(10) calls with CompositionTargetHelper.ExecuteAfterCompositionRenderingAsync(() => { }) across all RichSuggestBox tests in 0175d09. This properly waits for the composition rendering pass to complete instead of relying on a fixed delay.

Analysis: The intermittent failures appear to be caused by race conditions where Task.Delay(10) isn't always sufficient for the WinUI 3 RichTextBox to complete its text changes and fire events. This is consistent with the observation that failures happen primarily on WinUI 3 vs. WinUI 2, suggesting differences in the platform's text control event timing. The CompositionTargetHelper approach is already used in other tests across the toolkit and provides a more reliable synchronization mechanism.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• crl.godaddy.com
  • Triggering command: /home/REDACTED/work/Windows/.codeql-scratch/dbs/csharp/working/.dotnet/dotnet /home/REDACTED/work/Windows/.codeql-scratch/dbs/csharp/working/.dotnet/dotnet restore --no-dependencies /home/REDACTED/work/Windows/Windows/components/Animations/samples/Animations.Samples.csproj --packages /home/REDACTED/work/Windows/.codeql-scratch/dbs/csharp/working/packages /p:DisableImplicitNuGetFallbackFolder=true --verbosity normal /p:TargetFrameworkRootPath=/home/REDACTED/work/Windows/.codeql-scratch/dbs/csharp/working/emptyFakeDotnetRoot /p:NetCoreTargetingPackRoot=/home/REDACTED/work/Windows/.codeql-scratch/dbs/csharp/working/emptyFakeDotnetRoot (dns block)
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  • Triggering command: /home/REDACTED/work/Windows/.codeql-scratch/dbs/csharp/working/.dotnet/dotnet /home/REDACTED/work/Windows/.codeql-scratch/dbs/csharp/working/.dotnet/dotnet restore --no-dependencies /home/REDACTED/work/Windows/Windows/tooling/ProjectHeads/SingleComponent/Wasm/ProjectTemplate.Wasm.csproj --packages /home/REDACTED/work/Windows/.codeql-scratch/dbs/csharp/working/packages /p:DisableImplicitNuGetFallbackFolder=true --verbosity normal /p:TargetFrameworkRootPath=/home/REDACTED/work/Windows/.codeql-scratch/dbs/csharp/working/emptyFakeDotnetRoot /p:NetCoreTargetingPackRoot=/home/REDACTED/work/Windows/.codeql-scratch/dbs/csharp/working/emptyFakeDotnetRoot (dns block)
• ocsp.godaddy.com
  • Triggering command: /home/REDACTED/work/Windows/.codeql-scratch/dbs/csharp/working/.dotnet/dotnet /home/REDACTED/work/Windows/.codeql-scratch/dbs/csharp/working/.dotnet/dotnet restore --no-dependencies /home/REDACTED/work/Windows/Windows/components/Animations/samples/Animations.Samples.csproj --packages /home/REDACTED/work/Windows/.codeql-scratch/dbs/csharp/working/packages /p:DisableImplicitNuGetFallbackFolder=true --verbosity normal /p:TargetFrameworkRootPath=/home/REDACTED/work/Windows/.codeql-scratch/dbs/csharp/working/emptyFakeDotnetRoot /p:NetCoreTargetingPackRoot=/home/REDACTED/work/Windows/.codeql-scratch/dbs/csharp/working/emptyFakeDotnetRoot (dns block)
  • Triggering command: /home/REDACTED/work/Windows/.codeql-scratch/dbs/csharp/working/.dotnet/dotnet /home/REDACTED/work/Windows/.codeql-scratch/dbs/csharp/working/.dotnet/dotnet restore --no-dependencies /home/REDACTED/work/Windows/Windows/components/HeaderedControls/src/CommunityToolkit.WinUI.Controls.HeaderedControls.csproj --packages /home/REDACTED/work/Windows/.codeql-scratch/dbs/csharp/working/packages /p:DisableImplicitNuGetFallbackFolder=true --verbosity normal /p:TargetFrameworkRootPath=/home/REDACTED/work/Windows/.codeql-scratch/dbs/csharp/working/emptyFakeDotnetRoot /p:NetCoreTargetingPackRoot=/home/REDACTED/work/Windows/.codeql-scratch/dbs/csharp/working/emptyFakeDotnetRoot (dns block)
  • Triggering command: /home/REDACTED/work/Windows/.codeql-scratch/dbs/csharp/working/.dotnet/dotnet /home/REDACTED/work/Windows/.codeql-scratch/dbs/csharp/working/.dotnet/dotnet restore --no-dependencies /home/REDACTED/work/Windows/Windows/tooling/ProjectHeads/SingleComponent/Wasm/ProjectTemplate.Wasm.csproj --packages /home/REDACTED/work/Windows/.codeql-scratch/dbs/csharp/working/packages /p:DisableImplicitNuGetFallbackFolder=true --verbosity normal /p:TargetFrameworkRootPath=/home/REDACTED/work/Windows/.codeql-scratch/dbs/csharp/working/emptyFakeDotnetRoot /p:NetCoreTargetingPackRoot=/home/REDACTED/work/Windows/.codeql-scratch/dbs/csharp/working/emptyFakeDotnetRoot (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

[michael-hawker]

Re-running all the checks again to see how it holds up, optimistic that first pass passed.

[michael-hawker]

Re-running all checks again while waiting for @Arlodotexe review.