Remove exception message assertion from PerTestFrameworkTemplatesTests

[Copilot]

Three outerloop tests were failing because they expected a specific exception message pattern (System.ArgumentException.*Resource 'webfrontend' not found.) in dotnet test console output. The new test runners (MSTest with EnableMSTestRunner, xUnit v3, NUnit 4) no longer output full exception details to console by default—they only show test summaries.

Changes

• Removed the exception message pattern assertion from PerTestFrameworkTemplatesTests.cs
• Retained exit code and test summary validations, which are sufficient to verify:
  • Test project created correctly from template
  • Test compiles and runs
  • Test fails as expected (non-existent 'webfrontend' resource in empty template)

  var res = await cmd.ExecuteAsync($"test -c {config}");

  Assert.True(res.ExitCode != 0, $"Expected the tests project run to fail");
- Assert.Matches("System.ArgumentException.*Resource 'webfrontend' not found.", res.Output);
  Assert.Matches("Failed! * - Failed: *1, Passed: *0, Skipped: *0, Total: *1", res.Output);

Original prompt

The following tests are failing in the outerloop CI build:

• Aspire.Templates.Tests.MSTest_PerTestFrameworkTemplatesTests.TemplatesForIndividualTestFrameworks
• Aspire.Templates.Tests.Xunit_PerTestFrameworkTemplatesTests.TemplatesForIndividualTestFrameworks
• Aspire.Templates.Tests.Nunit_PerTestFrameworkTemplatesTests.TemplatesForIndividualTestFrameworks

The error message we are getting is:

Assert.Matches() Failure: Pattern not found in value
Regex: "System.ArgumentException.*Resource 'webfrontend' n"···
Value: "  Determining projects to restore...\r\nD:\a\_wo"···

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[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 -- 12444

Or

• Run remotely in PowerShell:

iex "& { $(irm https://raw.githubusercontent.com/dotnet/aspire/main/eng/scripts/get-aspire-cli-pr.ps1) } 12444"

[mitchdenny]

@DamianEdwards looks like the test run output format changed with the .NET 10 / test runner update and that is why these tests have been failing in the outer loop.

[Copilot]

Pull Request Overview

This PR fixes failing outerloop tests by removing an assertion that checked for exception message details in test output. The three test framework variants (MSTest, xUnit v3, NUnit 4) no longer emit full exception details to console by default with their new test runners, causing the pattern match to fail.

Key changes:

• Removed exception message assertion from TemplatesForIndividualTestFrameworks test method
• Retained exit code and test summary validations to ensure test behavior is still properly verified