public async void KillProcesses()
{
ICollection <Process> testProcesses = SpawnTestProcesses(2);
testProcesses.Should().NotContain(process => process.HasExited, "haven't killed anything yet");
await processKiller.DisableProcesses(cancellationTokenSource.Token);
testProcesses.Should().OnlyContain(process => process.HasExited, "all processes should have been killed");
}