How to generate code coverage report for asp.net unit tests in Azure DevOps build

I need guidance in generating code coverage report of Asp.net unit tests in azure build pipeline. My project is based on .Net Framework 4.6.

I am able to run all the unit tests using "visual studio test" task.

I tried the "report generator" task, but it require cobertura or jacoco etc xml files, which am unable to generate in the build pipeline.

Expectation - I want to get code coverage report for the runned unit tests which will show complete information like the lines coverage, branch coverage, function coverage etc. same as what "report generator" generates.

Note: I am able to generate the reports using opencover and reportgenerator on my local system but am unable to find a way to do the same in azure build pipeline.

To get the Code Coverage results in .Net framework you just need to enable it in the "Visual Studio Test" task:

If you are use .yml builds the syntax is:

- task: VSTest@2
  inputs:
    codeCoverageEnabled: true

Results:

Note: if you use Microsoft Hosted Agent you will see the results, if you use Self Hosted Agent you must Visual Studio Enterprise version to see the Code Coverage results.

If you want more detailed code coverage report you can use coverlet in .Net framework by install the tool during the pipeline and then generate the report. you can do with a PowerShell script:

dotnet tool install dotnet-reportgenerator --tool-path . --version 4.0.12
dotnet tool install coverlet.console --tool-path . --version 1.4.1
mkdir .\reports
$unitTestFile = gci -Recurse | ?{ $_.FullName -like "*bin\*test*.dll" }
$coverlet = "$pwd\coverlet.exe"
& $coverlet $unitTestFile.FullName --target "dotnet" --targetargs "vstest $($unitTestFile.FullName) --logger:trx" --format "cobertura"
gci -Recurse |
?{ $_.Name -eq "coverage.cobertura.xml"} |
%{ &"$pwd\reportgenerator.exe" "-reports:$($_.FullName)" "-targetdir:reports" "-reportstypes:HTMLInline;HTMLChart" }

Then add "Publish code coverage" task with these parameters:

Results: