Upgrade from MSTest from 3.7.3> has 'Code Coverage' issues

[prashanthnmurthy]

With MSTest package versions above 3.7.3 (Current version is 3.10.0), I’m unable to collect code coverage data using dotnet test in Azure DevOps pipelines with a Windows container image.

I receive the following message from the Dotnet test task: "Data collector 'Code Coverage' message: No code coverage data available. Profiler was not initialized."

I also tried using coverlet, but that didn’t work either and still shows 0% coverage.

Could you advise on a solution or suggest next steps?

Expected behavior

Code coverage tab should show the details as it was showing with MSTest 3.7.3

Actual behavior

Code coverage shows blank.

Additional context

[Youssef1313]

Thanks for reporting this @prashanthnmurthy
I'm moving to microsoft/codecoverage for further investigation on CC side.

[fhnaseer]

@prashanthnmurthy I would suggest to run dotnet test locally and see if you observe the same results or not. Can you check that Microsoft.CodeCoverage is part of the test project?

[prashanthnmurthy]

@fhnaseer Yes, I had the Microsoft.CodeCoverage as part of the test project, I also verified again locally with the same error.

Commands I used:
dotnet test dirs.proj --no-restore --no-build

[fhnaseer]

Where do you specify collect code coverage? Any runsettings?

Also, can you please try dotnet test --no-build --collect "Code Coverage" --diag log.dotnet.txt? And share these logs?

[prashanthnmurthy]

We use a runsettings file. Below is the run settings file.

CodeCoverage.zip

I executed the command above, and the log files can be found here.

log.dotnet.zip

I also added another assembly, Microsoft.Testing.Extensions.CodeCoverage, Microsoft.Testing.Extensions.TrxReport but it isn't functioning as expected.

[Youssef1313]

The packages Microsoft.Testing.Extensions.CodeCoverage and Microsoft.Testing.Extensions.TrxReport are only relevant for Microsoft.Testing.Platform. It seems that you are using VSTest and didn't migrate to Microsoft.Testing.Platform, so it's expected that Microsoft.Testing.Extensions.CodeCoverage, Microsoft.Testing.Extensions.TrxReport don't work.

[prashanthnmurthy]

@Youssef1313 Is it necessary to migrate to Microsoft.Testing.Platform, or are there alternative ways to obtain code coverage with MSTest/VSTest?

[Youssef1313]

While the migration is generally recommended, it should still be possible to obtain code coverage using MSTest with VSTest.

[fhnaseer]

I see that you have 4 test projects, however no tests were executed for 3 projects.

Code coverage collector will give this warning when no clients are connected, and hence it will generate an empty report => "No code coverage data available. Profiler was not initialized"

2 tests were executed, and a coverage report is generated at the end. Can you please check if the coverage report contains the right data? Or is it empty?

[fhnaseer]

@Youssef1313 We tried running the following workflows

1. MSTest Version 3.10.0
   1.2. dotnet test => coverage is not generated
   1.2. vstest.console.exe (17.14) => coverage is generated correctly
2. MSTest Version 3.7.3
   2.1. dotnet test => coverage is generated correctly
   2.2. vstest.console.exe (17.14) => coverage is generated correctly

Both versions of MSTest uses the same MS.CC 17.14.1 reference. I believe that there are some changes on MSTest side that does not work with dotnet test. Running the same project with vstest.console.exe generated correct coverage report.

[Youssef1313]

I cannot imagine how MSTest itself can have an impact on this and why dotnet test is different from vstest.console.exe.

Is there anything specific you can point out to? VSTest simply just calls MSTest to run tests via ITestExecutor. I don't see any interactions with CC 😕

Is there a different behavior with regards to running the tests with the MSTest upgrade?

[fhnaseer]

I cannot imagine how MSTest itself can have an impact on this and why dotnet test is different from vstest.console.exe.

Is there anything specific you can point out to? VSTest simply just calls MSTest to run tests via ITestExecutor. I don't see any interactions with CC 😕

Is there a different behavior with regards to running the tests with the MSTest upgrade?

Maybe @nohwnd can help in figuring this out.

[nohwnd]

<!-- file mstest268.csproj -->
<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <TargetFramework>net10.0</TargetFramework>
    <LangVersion>latest</LangVersion>
    <ImplicitUsings>enable</ImplicitUsings>
    <Nullable>enable</Nullable>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="MSTest.TestAdapter" Version="3.10.0" />
    <PackageReference Include="MSTest.TestFramework" Version="3.10.0" />
    <PackageReference Include="Microsoft.CodeCoverage" Version="17.14.1" />
    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.14.1" />
  </ItemGroup>

  <ItemGroup>
    <Using Include="Microsoft.VisualStudio.TestTools.UnitTesting" />
  </ItemGroup>

</Project>

# file mstest268.sln
Microsoft Visual Studio Solution File, Format Version 12.00
# Visual Studio Version 17
VisualStudioVersion = 17.5.2.0
MinimumVisualStudioVersion = 10.0.40219.1
Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "mstest268", "mstest268.csproj", "{F07FD354-CE88-7D9F-CDCC-D9950624BB7C}"
EndProject
Global
	GlobalSection(SolutionConfigurationPlatforms) = preSolution
		Debug|Any CPU = Debug|Any CPU
		Release|Any CPU = Release|Any CPU
	EndGlobalSection
	GlobalSection(ProjectConfigurationPlatforms) = postSolution
		{F07FD354-CE88-7D9F-CDCC-D9950624BB7C}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
		{F07FD354-CE88-7D9F-CDCC-D9950624BB7C}.Debug|Any CPU.Build.0 = Debug|Any CPU
		{F07FD354-CE88-7D9F-CDCC-D9950624BB7C}.Release|Any CPU.ActiveCfg = Release|Any CPU
		{F07FD354-CE88-7D9F-CDCC-D9950624BB7C}.Release|Any CPU.Build.0 = Release|Any CPU
	EndGlobalSection
	GlobalSection(SolutionProperties) = preSolution
		HideSolutionNode = FALSE
	EndGlobalSection
	GlobalSection(ExtensibilityGlobals) = postSolution
		SolutionGuid = {0569BCE6-BA2A-4CFE-B38A-E2F1A90BDDFA}
	EndGlobalSection
EndGlobal

// file MSTestSettings.cs
[assembly: Parallelize(Scope = ExecutionScope.MethodLevel)]

// file Test1.cs
namespace mstest268;

[TestClass]
public sealed class Test1
{
    [TestMethod]
    public void TestMethod1()
    {
    }
}

This works for me:

dotnet build
dotnet test --no-build --collect "Code Coverage" 

Test Parallelization enabled for S:\t\mstest268\bin\Debug\net10.0\mstest268.dll (Workers: 12, Scope: MethodLevel)
  mstest268 test succeeded (1.5s)

Test summary: total: 1, failed: 0, succeeded: 1, skipped: 0, duration: 1.5s
Build succeeded in 1.9s

Attachments:
  S:\t\mstest268\TestResults\0064bb74-f901-4ef7-8530-610235fb0207\jajares_RDESKTOP_2025-08-07.13_12_28.coverage