.NET Core on MacOS: Code Coverage with Coverlet

I wanted to check the code coverage on a .NET Core project I am working on. But I am on MacOS, and unfortunately, Visual Studio for Mac nor JetBrains Rider (on MacOS) does not support code coverage as of today. JetBrains is going to port dotCover to be cross-platform so we will have Rider + dotCover in near future which is something to look forward to.

I found this brilliant tool coverlet developed by Toni Solarin-Sodara. Coverlet is a cross-platform code coverage library for .NET Core, with support for line, branch and method coverage. I just gave it a try now, it looks amazing and with very little steps, I can get the code coverage.

First I need to add the coverlet.msbuild nuget package to the unit test project.

# From the folder which contains UnitTests.csproj file
dotnet add package coverlet.msbuild

# If the folder contains multiple .csproj files, specify the targetted .csproj file
dotnet add <MyProject.UnitTests.csproj> package coverlet.msbuild

Then I can just run,

dotnet test <MyProject.UnitTests.csproj> /p:CollectCoverage=true

But for some reason, I was getting this error "...coverlet.msbuild.targets: error: Failed to resolve assembly:...". After a little bit of googling, found this issue where it says to run dotnet test command with /p:CopyLocalLockFileAssemblies=true flag.

dotnet test <MyProject.UnitTests.csproj> /p:CollectCoverage=true /p:CopyLocalLockFileAssemblies=true

And yes, that did it and I am presented with most awaited code coverage.

Code Coverage

There are a lot of options that you can configure with coverlet and you should definitely try it.

Hope this helps.

Happy Coding.

Regards,

Jaliya