Refactor command code and add support for --help and --version.

utils/tests/pub/pub_test.dart

Index: utils/tests/pub/pub_test.dart
diff --git a/utils/tests/pub/pub_test.dart b/utils/tests/pub/pub_test.dart
index 55c93c45191cc7fe2b7b89f9def8bd30e1a6f211..b84a0dc7fa6aac9e29cbd7a747168abab1f7afae 100644
--- a/utils/tests/pub/pub_test.dart
+++ b/utils/tests/pub/pub_test.dart
@@ -9,26 +9,42 @@
 #import('test_pub.dart');
 #import('../../../lib/unittest/unittest.dart');
 
-main() {
-  group('running pub with no command', () {
-    testPub('displays usage',
-      args: [],
-      output: """
-      Pub is a package manager for Dart.
+final USAGE_STRING = """
+    Pub is a package manager for Dart.
 
-      Usage:
+    Usage:
 
-        pub command [arguments]
+      pub command [arguments]
 
-      The commands are:
+    The commands are:
 
-        list      print the contents of repositories
-        update    update a package's dependencies
-        version   print Pub version
+      list      print the contents of repositories
+      update    update the current package's dependencies to the latest versions
+      version   print Pub version
 
-      Use "pub help [command]" for more information about a command.
-      """);
-  });
+    Use "pub help [command]" for more information about a command.
+    """;
+
+final VERSION_STRING = '''
+    Pub 0.0.0
+    ''';
+
+main() {
+  testPub('running pub with no command displays usage',
+    args: [],
+    output: USAGE_STRING);
+
+  testPub('running pub with just --help displays usage',
+    args: ['--help'],
+    output: USAGE_STRING);
+
+  testPub('running pub with just -h displays usage',
+    args: ['-h'],
+    output: USAGE_STRING);
+
+  testPub('running pub with just --version displays version',
+    args: ['--version'],
+    output: VERSION_STRING);
 
   group('an unknown command', () {
     testPub('displays an error message',
@@ -108,7 +124,5 @@ updateCommand() {
 versionCommand() {
   testPub('displays the current version',
     args: ['version'],
-    output: '''
-    Pub 0.0.0
-    ''');
+    output: VERSION_STRING);
 }