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

utils/tests/pub/test_pub.dart

 // Copyright (c) 2012, 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.
 
 /**
  * Test infrastructure for testing pub. Unlike typical unit tests, most pub
  * tests are integration tests that stage some stuff on the file system, run
  * pub, and then validate the results. This library provides an API to build
  * tests like that.
  */
@@ skipping 69 matching lines @@
       deleteSandboxIfCreated();
     });
 
     future.handleException((error) {
       deleteSandboxIfCreated();
     });
   });
 }
 
 Future<Directory> _setUpSandbox() {
-  return createTempDir('pub-test-sandbox-');
+  return cleanDir('pub-test-sandbox');
 }
 
 Future _setUpCache(Directory sandboxDir, List<Descriptor> cache) {
   // No cache.
   if (cache == null) return new Future.immediate(null);
 
   return dir('pub-cache', cache).create(sandboxDir);
 }
 
 Future _setUpApp(Directory sandboxDir, Descriptor app) {
@@ skipping 84 matching lines @@
 
   Descriptor(this.name);
 
   /**
    * Creates the file or directory within [dir]. Returns a [Future] that is
    * completed after the creation is done.
    */
   abstract Future create(String dir);
 
   /**
-   * Validates that this descriptor correctly matches the actual file system
-   * entry at [path]. Returns a [Future] that completes when the validation is
-   * done.
+   * Validates that this descriptor correctly matches the corresponding file
+   * system entry within [dir]. Returns a [Future] that completes when the
+   * validation is done.
    */
-  abstract Future<bool> validate(String path);
+  abstract Future<bool> validate(String dir);
 }
 
 /**
  * Describes a file. These are used both for setting up an expected directory
  * tree before running a test, and for validating that the file system matches
  * some expectations after running it.
  */
 class FileDescriptor extends Descriptor {
   /**
    * The text contents of the file.
@@ skipping 70 matching lines @@
     // Validate each of the items in this directory.
     final entryFutures = contents.map(
         (entry) => entry.validate(join(path, name)));
 
     // If they are all valid, the directory is valid.
     return Futures.wait(entryFutures).transform((entries) {
       return !entries.some((valid) => !valid);
     });
   }
 }