Coverlet - exclusion of code coverage study by attribute

Exclusion by attribute (ExcludeByAttribute)

When I was looking for 100% code coverage with unit tests, I faced the problem of how to exclude automatically generated code. Unfortunately, this information was terribly hard for me to find, so I am sharing it here.

As the documentation shows, each attribute intended for exclusion must be passed separately:

--exclude-by-attribute 'Obsolete' --exclude-by-attribute'GeneratedCode' --exclude-by-attribute 'CompilerGenerated'

More holistic example:

coverlet /path/to/test-assembly.dll --target "dotnet" --targetargs "test /path/to/test-project --no-build" --exclude-by-attribute 'Obsolete' --exclude-by-attribute'GeneratedCode'

Nuke

To add an exclusion to Nuke, you need to modify the parameters of the code coverage. Taking a piece of code from the second part about Nuke, one line would need to be added:

CoverletSettings PrepareCoverageSettingsForCoveringProject(Project project, CoverletSettings settings,
    DotNetTestSettings coverageTestSettings, ref string previousCoverageFileResult)
{
    var assemblyPath = FindAssemblyForProject(project);
    var coverageResultDirectory = TestResultDirectory / project.Name;

    settings = settings
        .SetAssembly(assemblyPath)
        .SetProcessArgumentConfigurator(_ => _.Add(@"--exclude-by-attribute CompilerGeneratedAttribute --exclude-by-attribute GeneratedCodeAttribute")) (1)
        .SetOutput(coverageResultDirectory + "/")
        .SetTargetSettings(coverageTestSettings
            .EnableNoBuild()
            .SetProjectFile(project));

    settings = MergeCoverageResultsWithPreviousRun(previousCoverageFileResult, settings);
    previousCoverageFileResult = SetThresholdForLastRun(project, coverageResultDirectory, ref settings);

    return settings;
}

1	This one line is enough to exclude code marked with `CompilerGeneratedAttribute` and `GeneratedCodeAttribute` attributes.