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

test/implicit_dependency_test.dart

 // Copyright (c) 2013, 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.
 
 import 'package:pub/src/barback.dart' as barback;
 import 'package:pub_semver/pub_semver.dart';
 
 import 'descriptor.dart' as d;
 import 'test_pub.dart';
 
 main() {
   forBothPubGetAndUpgrade((command) {
     integration("implicitly constrains it to versions pub supports", () {
       servePackages((builder) {
         builder.serve("barback", current("barback"));
         builder.serve("stack_trace", previous("stack_trace"));
         builder.serve("stack_trace", current("stack_trace"));
         builder.serve("stack_trace", nextPatch("stack_trace"));
         builder.serve("stack_trace", max("stack_trace"));
         builder.serve("source_span", current("source_span"));
         builder.serve("async", current("async"));
       });
 
       d.appDir({
         "barback": "any"
       }).create();
 
       pubCommand(command);
 
-      d.packagesDir({"stack_trace": nextPatch("stack_trace")}).validate();
+      d.appPackagesFile({
+        "async": current("async"),
+        "barback": current("barback"),
+        "source_span": current("source_span"),
+        "stack_trace": nextPatch("stack_trace")
+      }).validate();
     });
 
     integration("pub's implicit constraint uses the same source and "
         "description as a dependency override", () {
       servePackages((builder) {
         builder.serve("barback", current("barback"));
         builder.serve("stack_trace", nextPatch("stack_trace"));
         builder.serve("source_span", current("source_span"));
         builder.serve("async", current("async"));
       });
@@ skipping 10 matching lines @@
           "dependency_overrides": {
             "stack_trace": {"path": "../stack_trace"},
           }
         })
       ]).create();
 
       pubCommand(command);
 
       // Validate that we're using the path dependency version of stack_trace
       // rather than the hosted version.
-      d.packagesDir({
-        "stack_trace": current("stack_trace")
+      d.appPackagesFile({
+        "async": current("async"),
+        "barback": current("barback"),
+        "source_span": current("source_span"),
+        "stack_trace": "../stack_trace"
       }).validate();
     });
 
     integration("doesn't add a constraint if barback isn't in the package "
         "graph", () {
       servePackages((builder) {
         builder.serve("stack_trace", previous("stack_trace"));
         builder.serve("stack_trace", current("stack_trace"));
         builder.serve("stack_trace", nextPatch("stack_trace"));
         builder.serve("stack_trace", max("stack_trace"));
         builder.serve("source_span", current("source_span"));
         builder.serve("async", current("async"));
       });
 
       d.appDir({
         "stack_trace": "any"
       }).create();
 
       pubCommand(command);
 
-      d.packagesDir({"stack_trace": max("stack_trace")}).validate();
+      d.appPackagesFile({"stack_trace": max("stack_trace")}).validate();
     });
   });
 
   integration("unlocks if the locked version doesn't meet pub's "
       "constraint", () {
     servePackages((builder) {
       builder.serve("barback", current("barback"));
       builder.serve("stack_trace", previous("stack_trace"));
       builder.serve("stack_trace", current("stack_trace"));
       builder.serve("source_span", current("source_span"));
       builder.serve("async", current("async"));
     });
 
     d.appDir({"barback": "any"}).create();
 
     // Hand-create a lockfile to pin the package to an older version.
     createLockFile("myapp", hosted: {
       "barback": current("barback"),
       "stack_trace": previous("stack_trace")
     });
 
     pubGet();
 
     // It should be upgraded.
-    d.packagesDir({
+    d.appPackagesFile({
+      "async": current("async"),
+      "barback": current("barback"),
+      "source_span": current("source_span"),
       "stack_trace": current("stack_trace")
     }).validate();
   });
 }
 
 String current(String packageName) =>
     barback.pubConstraints[packageName].min.toString();
 
 String previous(String packageName) {
   var constraint = barback.pubConstraints[packageName];
   return new Version(constraint.min.major, constraint.min.minor - 1, 0)
       .toString();
 }
 
 String nextPatch(String packageName) =>
     barback.pubConstraints[packageName].min.nextPatch.toString();
 
 String max(String packageName) =>
     barback.pubConstraints[packageName].max.toString();