dotnet new console -o myconsoleapp

dotnet new xunit -o myconsoleapp.tests

dotnet add ./myconsoleapp.tests reference ./myconsoleapp

dotnet test ./myconsoleapp.tests

dotnet build ./myconsoleapp.tests
dotnet ./myconsoleapp.tests/bin/Debug/netcoreapp2.2/myconsoleapp.dll

A fatal error was encountered. The library 'hostpolicy.dll' required to execute the application was not found in 'myconsoleapp.tests/bin/Debug/netcoreapp2.2/'.
Failed to run as a self-contained app. If this should be a framework-dependent app, add the myconsoleapp.tests/bin/Debugnetcoreapp2.2/myconsoleapp.runtimeconfig.json file specifying the appropriate framework.

using(var sut = Process.Start(@"<path-to-the-executable>"))
{
  sut.WaitForExit();
  var actual = sut.ExitCode;
  Assert.Equal(-1,actual);
}