Function run_session 

pub fn run_session(
    bundle: &Bundle,
    source_mod: &Path,
    dependencies: &[DependencyMod],
    session_dir: &Path,
    installation: &Installation,
    options: &RunOptions,
) -> Result<SessionOutcome>

Build the runtime layer, launch the game, wait for every case to finish (or time out), collect the logs, and tear the layer down. session_dir is where the throwaway profile and logs live; source_mod is the mod under test.