Use helper methods for running pub.

sdk/lib/_internal/pub/test/install/hosted/repair_cache_test.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.
 
 library pub_tests;
 
 import 'package:pathos/path.dart' as path;
 
 import '../../../lib/src/io.dart';
 import '../../descriptor.dart' as d;
@@ skipping 12 matching lines @@
             d.libPubspec("foo", "1.2.3"),
             // Note: empty "lib" directory.
             d.dir("lib", [])
           ])
         ])))
       ])
     ]).create();
 
     d.appDir([dependencyMap("foo", "1.2.3")]).create();
 
-    schedulePub(args: ['install'],
-        output: new RegExp("Dependencies installed!\$"));
+    pubInstall();
 
     d.cacheDir({"foo": "1.2.3"}).validate();
     d.packagesDir({"foo": "1.2.3"}).validate();
   });
 
   integration('re-installs a package if it has no pubspec', () {
     servePackages([packageMap("foo", "1.2.3")]);
 
     // Set up a cache with a broken foo package.
     d.dir(cachePath, [
       d.dir('hosted', [
         d.async(port.then((p) => d.dir('localhost%58$p', [
           d.dir("foo-1.2.3", [
             d.libDir("foo")
             // Note: no pubspec.
           ])
         ])))
       ])
     ]).create();
 
     d.appDir([dependencyMap("foo", "1.2.3")]).create();
 
-    schedulePub(args: ['install'],
-        output: new RegExp("Dependencies installed!\$"));
+    pubInstall();
 
     d.cacheDir({"foo": "1.2.3"}).validate();
     d.packagesDir({"foo": "1.2.3"}).validate();
   });
 }