anchor.diff:          '';
   
         passthru = driver.passthru;
  +
  +      inherit pos;
       };
   
   
  
positive.code:       driver = mkDriver null;
        driverInteractive = mkDriver pkgs.qemu;
  
        test = passMeta (runTests driver);
  
        nodeNames = builtins.attrNames driver.nodes;
        invalidNodeNames = lib.filter
  
negative.code: 
    # Run an automated test suite in the given virtual network.
    # `driver' is the script that runs the network.
    runTests = { driver, pos }:
      stdenv.mkDerivation {
        name = "vm-test-run-${driver.testName}";
  
  