Add SonarCloud analysis with code coverage

[Copilot]

• Add SonarCloud workflow (.github/workflows/sonarcloud.yml)
• Replace coverlet.collector with Microsoft.Testing.Extensions.CodeCoverage in tests/Directory.Build.props
• Remove sonar-project.properties (incompatible with dotnet-sonarscanner)
• Switch from VS Coverage XML to Cobertura format output
• Fix coverage property: use sonar.coverageReportPaths for SonarQube Generic Coverage format
• Fix glob/format mismatch: add reportgenerator step to convert *.cobertura.xml → coverage/SonarQube.xml (Generic Coverage XML), since sonar.coverageReportPaths does not support globs and expects Generic Coverage XML schema, not Cobertura

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[304NotModified]

@copilot could we use ms packages instead of coverlet?

[Copilot]

@copilot could we use ms packages instead of coverlet?

Done in af9e491. Replaced coverlet.collector with Microsoft.Testing.Extensions.CodeCoverage (v18.*), which integrates natively with TUnit's Microsoft.Testing.Platform runner. The workflow now passes -- --coverage --coverage-output-format xml to the test command and uses sonar.cs.vscoveragexml.reportsPaths for SonarCloud.

[304NotModified]

@copilot it fails.

[Copilot]

@copilot it fails.

Fixed in e3113af. The failure was caused by sonar-project.properties — dotnet-sonarscanner explicitly rejects that file (it's for the SonarScanner CLI, not the .NET scanner). Deleted it; the project key and org are already supplied via /k: and /o: in the begin step.

[304NotModified]

@copilot coverage is not visible in sonarcloud?

[Copilot]

@copilot coverage is not visible in sonarcloud?

Fixed in 1ffa120. The VS Coverage XML format (sonar.cs.vscoveragexml.reportsPaths) was being parsed but source file paths weren't matching, causing the Zero Coverage sensor to report nothing. Switched to Cobertura format: --coverage-output-format cobertura + sonar.cs.cobertura.reportsPaths="**/TestResults/**/*.cobertura.xml" — this is the format SonarCloud maps reliably.

[304NotModified]

@copilot still on sonarcloud.io

.Coverage
There are not enough lines to compute coverage

[Copilot]

@copilot still on sonarcloud.io

.Coverage
...

Fixed in fe4e000. The problem was that sonar.cs.cobertura.reportsPaths is not a recognized property for the SonarCloud C# plugin (it only supports sonar.cs.opencover.reportsPaths, sonar.cs.vscoveragexml.reportsPaths, and sonar.cs.dotcover.reportsPaths), so the coverage import sensor never ran. Changed to sonar.coverageReportPaths, which is the correct generic SonarCloud property for Cobertura XML format and works across all languages including C#.

[304NotModified]

@copilot

/home/runner/work/SLNX-validator/SLNX-validator//TestResults//.cobertura.xml
20:52:34.685 ERROR: Error during parsing of the generic coverage report '/home/runner/work/SLNX-validator/SLNX-validator//TestResults//.cobertura.xml'. Look at SonarQube documentation to know the expected XML format.
20:52:35.023 The scanner engine did not complete successfully

[Copilot]

@copilot

/home/runner/work/SLNX-validator/SLNX-validator//TestResults//*.cobertura.xml
...

Fixed in 27a134a. Two issues were at play:

1. sonar.coverageReportPaths does not support glob patterns — it was trying to open the literal string **/TestResults/**/*.cobertura.xml as a file.
2. sonar.coverageReportPaths expects SonarQube Generic Coverage XML (a different schema), not Cobertura XML.

Added dotnet-reportgenerator-globaltool and a conversion step that runs after tests:

reportgenerator -reports:"**/TestResults/**/*.cobertura.xml" -targetdir:coverage -reporttypes:SonarQube

This converts all Cobertura files into coverage/SonarQube.xml (Generic Coverage XML), which sonar.coverageReportPaths="coverage/SonarQube.xml" then reads correctly.

[304NotModified]

Not sure if the code coverage now works. Will see after merge