anchor.diff:  }
   
   void usage(ArgParser parser) {
  -  print("Usage: dart run_tests.dart [--build] [--configs=...] "
  +  print("Usage: dart run_tests.dart [--build] [-2] [-1] [--configs=...]"
         "<first file> [last file]");
     print("\n");
     print("Example:");
  
positive.code:     } else {
        passed.add(name);
      }
    }
  
    if (failed.length == 0) {
  
negative.code:   "analyzer-checked-strong": [analyzer, noRuntime, checked, strong, useSdk],
    "analyzer-strong": [analyzer, noRuntime, strong, useSdk],
    "dart2js": [dart2js, chrome, useSdk, dart2jsBatch],
    "dart2js-d8-checked": [
      dart2js,
      d8,
      checked,
      fastStartup,
      useSdk,
      dart2jsBatch
    ],
    "dart2js-jsshell": [dart2js, jsshell, fastStartup, useSdk, dart2jsBatch],
    // TODO(rnystrom): Is it worth running dart2js on Firefox too?
    "dartdevc": [dartdevc, chrome, useSdk, strong],
  };
  
  /// A subset of the configurations that run quickly and give a decent amount of
  /// coverage for the platforms that do not implement Dart 2.0 yet.
  final oneConfigs = const [
    "vm",
    "vm-checked",
    "analyzer",
    "analyzer-checked",
    "dart2js",
    "dart2js-d8-checked",
    "dartdevc",
  ];
  
  /// The configurations that should correctly implement Dart 2.0 (more or less)
  /// already.
  final twoConfigs = const [
    "analyzer-checked-strong",
    "analyzer-strong",
    "dartdevc"
  ];
  
  final buildSteps = [
    // The SDK, which also builds the VM.
  