anchor.diff:        # Skip linting (mainly intended for faster dev cycles)
       , skipLint ? false
       , passthru ? {}
  +    , # For meta.position
  +      pos ? # position used in error messages and for meta.position
  +        (if t.meta.description or null != null
  +          then builtins.unsafeGetAttrPos "description" t.meta
  +          else builtins.unsafeGetAttrPos "testScript" t)
       , ...
       } @ t:
       let
  
positive.code: 
    # Run an automated test suite in the given virtual network.
    # `driver' is the script that runs the network.
    runTests = driver:
      stdenv.mkDerivation {
        name = "vm-test-run-${driver.testName}";
  
  
negative.code:       driver = mkDriver null;
        driverInteractive = mkDriver pkgs.qemu;
  
        test = passMeta (runTests { inherit driver pos; });
  
        nodeNames = builtins.attrNames driver.nodes;
        invalidNodeNames = lib.filter
  