Support a --version flag.

lib/src/executable.dart

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 // TODO(nweiz): This is under lib so that it can be used by the unittest dummy
 // package. Once that package is no longer being updated, move this back into
 // bin.
 library test.executable;
 
 import 'dart:async';
@@ skipping 56 matching lines @@
     if (transformer is String) return transformer == 'test/pub_serve';
     if (transformer is! Map) return false;
     if (transformer.keys.length != 1) return false;
     return transformer.keys.single == 'test/pub_serve';
   });
 }
 
 void main(List<String> args) {
   _parser.addFlag("help", abbr: "h", negatable: false,
       help: "Shows this usage information.");
+  _parser.addFlag("version", negatable: false,
+      help: "Shows the package's version.");
   _parser.addOption("package-root", hide: true);
   _parser.addOption("name",
       abbr: 'n',
       help: 'A substring of the name of the test to run.\n'
           'Regular expression syntax is supported.');
   _parser.addOption("plain-name",
       abbr: 'N',
       help: 'A plain-text substring of the name of the test to run.');
   _parser.addOption("platform",
       abbr: 'p',
@@ skipping 20 matching lines @@
     _printUsage(error.message);
     exitCode = exit_codes.usage;
     return;
   }
 
   if (options["help"]) {
     _printUsage();
     return;
   }
 
+  if (options["version"]) {
+    if (!_printVersion()) {
+      stderr.writeln("Couldn't find version number.");
+      exitCode = exit_codes.data;
+    }
+    return;
+  }
+
   var color = options["color"];
   if (color == null) color = canUseSpecialChars;
 
   var pubServeUrl;
   if (options["pub-serve"] != null) {
     pubServeUrl = Uri.parse("http://localhost:${options['pub-serve']}");
     if (!_usesTransformer) {
       stderr.write('''
 When using --pub-serve, you must include the "test/pub_serve" transformer in
 your pubspec:
@@ skipping 158 matching lines @@
     output = stderr;
   }
 
   output.write("""$message
 
 Usage: pub run test:test [files or directories...]
 
 ${_parser.usage}
 """);
 }
+
+/// Prints the version number of the test package.
+///
+/// This loads the version number from the current package's lockfile. It
+/// returns true if it successfully printed the version number and false if it
+/// couldn't be loaded.
+bool _printVersion() {
+  var lockfile;
+  try {
+    lockfile = loadYaml(new File("pubspec.lock").readAsStringSync());
+  } on FormatException catch (_) {
+    return false;
+  } on IOException catch (_) {
+    return false;
+  }
+
+  if (lockfile is! Map) return false;
+  var packages = lockfile["packages"];
+  if (packages is! Map) return false;
+  var package = packages["test"];
+  if (package is! Map) return false;
+
+  var source = package["source"];
+  if (source is! String) return false;
+
+  switch (source) {
+    case "hosted":
+      var version = package["version"];
+      if (version is! String) return false;
+
+      print(version);
+      return true;
+
+    case "git":
+      var version = package["version"];
+      if (version is! String) return false;
+      var description = package["description"];
+      if (description is! Map) return false;
+      var ref = description["resolved-ref"];
+      if (ref is! String) return false;
+
+      print("$version (${ref.substring(0, 7)})");
+      return true;
+
+    case "path":
+      var version = package["version"];
+      if (version is! String) return false;
+      var description = package["description"];
+      if (description is! Map) return false;
+      var path = description["path"];
+      if (path is! String) return false;
+
+      print("$version (from $path)");
+      return true;
+
+    default: return false;
+  }
+}