Using dotCover with Visual Studio Tests, you should build the test dll first
VSTestSettings testSettings = new VSTestSettings()
.SetTestAssemblies(GlobFiles(SourceDirectory, "**/bin/debug/Tests.dll"))
.SetLogger($"Trx;LogFileName={RootDirectory / "Tests.trx"}");
DotCoverTasks.DotCoverCover(s => s
.SetTargetSettings(testSettings)
.SetOutputFile(ArtifactsDirectory / "Coverage.dcvr")
);https://www.jetbrains.com/help/dotcover/Running_Coverage_Analysis_from_the_Command_LIne.html