Start pulling pub from its own repo.

sdk/lib/_internal/pub/test/upgrade/report/describes_change_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.
-
-library pub_tests;
-
-import '../../descriptor.dart' as d;
-import '../../test_pub.dart';
-
-main() {
-  initConfig();
-  integration("shows how package changed from previous lockfile", () {
-    servePackages((builder) {
-      builder.serve("unchanged", "1.0.0");
-      builder.serve("version_changed", "1.0.0");
-      builder.serve("version_changed", "2.0.0");
-      builder.serve("source_changed", "1.0.0");
-    });
-
-    d.dir("source_changed", [
-      d.libDir("source_changed"),
-      d.libPubspec("source_changed", "2.0.0")
-    ]).create();
-
-    d.dir("description_changed_1", [
-      d.libDir("description_changed"),
-      d.libPubspec("description_changed", "1.0.0")
-    ]).create();
-
-    d.dir("description_changed_2", [
-      d.libDir("description_changed"),
-      d.libPubspec("description_changed", "1.0.0")
-    ]).create();
-
-    // Create the first lockfile.
-    d.appDir({
-      "unchanged": "any",
-      "version_changed": "1.0.0",
-      "source_changed": "any",
-      "description_changed": {"path": "../description_changed_1"}
-    }).create();
-
-    pubGet();
-
-    // Change the pubspec.
-    d.appDir({
-      "unchanged": "any",
-      "version_changed": "any",
-      "source_changed": {"path": "../source_changed"},
-      "description_changed": {"path": "../description_changed_2"}
-    }).create();
-
-    // Upgrade everything.
-    pubUpgrade(output: new RegExp(r"""
-Resolving dependencies\.\.\..*
-. description_changed 1\.0\.0 from path \.\.[/\\]description_changed_2 \(was 1\.0\.0 from path \.\.[/\\]description_changed_1\)
-. source_changed 2\.0\.0 from path \.\.[/\\]source_changed \(was 1\.0\.0\)
-. unchanged 1\.0\.0
-. version_changed 2\.0\.0 \(was 1\.0\.0\)
-""", multiLine: true));
-  });
-}