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

Question

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.

Answer 1

For anyone looking for code coverage in Azure Devops (using classic editor, without Yaml), in current .NET (core) 5, with xUnit tests:

1. In your xUnit test project, add following (it generally comes by default in .NET 5, xUnit template now):

   \<PackageReference Include="coverlet.collector" Version="3.0.3" /\>

   Keep checking for new version.

2. Head to Azure devops, create pipeline using classic editor. Do the restore, build steps. (Or you can choose dotnet core template as below):

3. In the test command of dotnet core task, add argument - --collect:"XPlat Code Coverage". Remember "XPlat Code Coverage" is friendly name and case sensitive. Your test command would look like: Check this checkbox if you want to publish your test results: Publish test results and code coverage, but it won't publish code coverage. The functionality is not yet working (at least not in non-windows).

4. Next add - Publish code coverage results task. Choose "Code coverage tool" as "Cobertura" and in "Summary file" field, add $(Agent.TempDirectory)/**/coverage.cobertura.xml. Looks like this:

5. Save and Queue (in any agent, I use Ubuntu) and see the result once pipeline run completes:

Answer 2

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: