Make "--no-packages-dir" the default.

test/get/path/relative_path_test.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS d.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 d.file.
 
 import 'package:path/path.dart' as path;
 import 'package:pub/src/lock_file.dart';
 import 'package:pub/src/source_registry.dart';
 import 'package:scheduled_test/scheduled_test.dart';
 
 import '../../descriptor.dart' as d;
 import '../../test_pub.dart';
 
 main() {
   integration("can use relative path", () {
     d.dir("foo", [
       d.libDir("foo"),
       d.libPubspec("foo", "0.0.1")
     ]).create();
 
     d.dir(appPath, [
       d.appPubspec({
         "foo": {"path": "../foo"}
       })
     ]).create();
 
     pubGet();
 
-    d.dir(packagesPath, [
-      d.dir("foo", [
-        d.file("foo.dart", 'main() => "foo";')
-      ])
-    ]).validate();
+    d.appPackagesFile({
+      "foo": "../foo"
+    }).validate();
   });
 
-  integration("path is relative to containing d.pubspec", () {
+  integration("path is relative to containing pubspec", () {
     d.dir("relative", [
       d.dir("foo", [
         d.libDir("foo"),
         d.libPubspec("foo", "0.0.1", deps: {
           "bar": {"path": "../bar"}
         })
       ]),
       d.dir("bar", [
         d.libDir("bar"),
         d.libPubspec("bar", "0.0.1")
       ])
     ]).create();
 
     d.dir(appPath, [
       d.appPubspec({
         "foo": {"path": "../relative/foo"}
       })
     ]).create();
 
     pubGet();
 
-    d.dir(packagesPath, [
-      d.dir("foo", [
-        d.file("foo.dart", 'main() => "foo";')
-      ]),
-      d.dir("bar", [
-        d.file("bar.dart", 'main() => "bar";')
-      ])
-    ]).validate();
+    d.appPackagesFile({
+      "foo": "../relative/foo",
+      "bar": "../relative/bar"
+    }).validate();
   });
 
   integration("relative path preserved in the lockfile", () {
     d.dir("foo", [
       d.libDir("foo"),
       d.libPubspec("foo", "0.0.1")
     ]).create();
 
     d.dir(appPath, [
       d.appPubspec({
         "foo": {"path": "../foo"}
       })
     ]).create();
 
     pubGet();
 
     schedule(() {
       var lockfilePath = path.join(sandboxDir, appPath, "pubspec.lock");
       var lockfile = new LockFile.load(lockfilePath, new SourceRegistry());
       var description = lockfile.packages["foo"].description;
 
       expect(path.isRelative(description["path"]), isTrue);
     });
   });
 }