Analyze your Code Coverage with Coverlet

Coverlet is a cross platform code coverage framework for .NET, with support for line, branch and method coverage. It works with .NET Framework on Windows and .NET Core on all supported platforms.

To see the available Coverlet APIs in FAKE, please see the API-Reference for the Coverlet module.

Minimal working example

To work with Coverlet, you must first:

• Add the NuGet reference coverlet.msbuild to your test projects (and only your test projects!).
• Ensure that these test projects are marked as such with a property <IsTestProject>true</IsTestProject>.

Then, Coverlet will run as part of dotnet test using Coverlet.withDotNetTestOptions:

#r "paket:
nuget Fake.DotNet.Testing.Coverlet //"
open Fake.DotNet
open Fake.DotNet.Testing

DotNet.test (fun p ->
    { p with 
        // Your dotnet test configuration here...
        Configuration = DotNet.BuildConfiguration.Release
    }
    |> Coverlet.withDotNetTestOptions (fun p ->
        { p with
            Output = "coverage.json"
        }))
    "tests/MyProject.fsproj"

Full example

Following FSI script shows a complete usage of Coverlet module:

#r "paket:
nuget Fake.DotNet.Testing.Coverlet //"
open Fake.DotNet
open Fake.DotNet.Testing

DotNet.test (fun p ->
    { p with 
        // Your dotnet test configuration here...
        Configuration = DotNet.BuildConfiguration.Release
    }
    |> Coverlet.withDotNetTestOptions (fun p ->
        { p with
            OutputFormat = [Coverlet.OutputFormat.OpenCover]
            Output = "coverage.xml"
            Include = [
                // Include all namespaces from assemblies whose name starts with MyProject
                "MyProject.*", "*"
            ]
            Exclude = [
                // Exclude all namespaces from assemblies whose name ends with .Test or .Tests
                "*.Tests?", "*"
                // Exclude all namespaces starting with System., even in included assemblies
                "*", "System.*"
            ]
            // Exclude assemblies, types and methods marked with these attributes
            ExcludeByAttribute = ["MyCustomIgnoreCoverageAttribute"]
            // Exclude all code from these files
            ExcludeByFile = ["AssemblyInfo.fs"; "Program.fs"]
            // Merge results with results from another coverage session
            // (which must have OutputFormat = Json)
            MergeWith = Some "other-coverage.json"
            // Fail if total line coverage is below 80%
            Threshold = Some 80
            TresholdType = Coverlet.ThresholdType.Line
            ThresholdStat = Coverlet.ThresholdState.Total
            // Generate links to SourceLink URLs rather than local paths
            UseSourceLink = true
        }))
    "tests/MyProject.fsproj"