Add a "cache add" command to download packages to the cache.

sdk/lib/_internal/pub/test/cache/add/all_adds_all_matching_versions_test.dart

Index: sdk/lib/_internal/pub/test/cache/add/all_adds_all_matching_versions_test.dart
diff --git a/sdk/lib/_internal/pub/test/cache/add/all_adds_all_matching_versions_test.dart b/sdk/lib/_internal/pub/test/cache/add/all_adds_all_matching_versions_test.dart
new file mode 100644
index 0000000000000000000000000000000000000000..a63627b9baa23211473daf749377c4adecf9697e
--- /dev/null
+++ b/sdk/lib/_internal/pub/test/cache/add/all_adds_all_matching_versions_test.dart
@@ -0,0 +1,32 @@
+// Copyright (c) 2014, 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('"--all" adds all matching versions of the package', () {
+    servePackages([
+      packageMap("foo", "1.2.2"),
+      packageMap("foo", "1.2.3-dev"),
+      packageMap("foo", "1.2.3"),
+      packageMap("foo", "2.0.0-dev"),
+      packageMap("foo", "2.0.0")
+    ]);
+
+    schedulePub(args: ["cache", "add", "foo", "-v", ">=1.0.0 <2.0.0", "--all"],
+        output: '''
+          Downloading foo 1.2.2...
+          Downloading foo 1.2.3-dev...
+          Downloading foo 1.2.3...
+          Downloading foo 2.0.0-dev...''');
+
+    d.cacheDir({"foo": "1.2.2"}).validate();
+    d.cacheDir({"foo": "1.2.3-dev"}).validate();
+    d.cacheDir({"foo": "1.2.3"}).validate();
+  });
+}