Install before starting the server if the lockfile is out of date.

sdk/lib/_internal/pub/test/serve/installs_first_if_git_ref_changed_test.dart

Index: sdk/lib/_internal/pub/test/serve/installs_first_if_git_ref_changed_test.dart
diff --git a/sdk/lib/_internal/pub/test/serve/installs_first_if_git_ref_changed_test.dart b/sdk/lib/_internal/pub/test/serve/installs_first_if_git_ref_changed_test.dart
new file mode 100644
index 0000000000000000000000000000000000000000..a1906fd77cd755799776567921e14140525fb72f
--- /dev/null
+++ b/sdk/lib/_internal/pub/test/serve/installs_first_if_git_ref_changed_test.dart
@@ -0,0 +1,48 @@
+// 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 file.
+
+library pub_tests;
+
+import 'dart:io';
+import 'dart:json' as json;
+
+import '../descriptor.dart' as d;
+import '../test_pub.dart';
+import 'utils.dart';
+
+main() {
+  initConfig();
+  integration("installs first if a git dependency's ref doesn't match the one "
+      "in the lock file", () {
+    var repo = d.git('foo.git', [
+      d.libDir('foo', 'before'),
+      d.libPubspec('foo', '1.0.0')
+    ]);
+    repo.create();
+    var commit1 = repo.revParse('HEAD');
+
+    d.git('foo.git', [
+      d.libDir('foo', 'after'),
+      d.libPubspec('foo', '1.0.0')
+    ]).commit();
+
+    var commit2 = repo.revParse('HEAD');
+
+    // Lock it to the ref of the first commit.
+    d.appDir({
+      "foo": {"git": {"url": "../foo.git", "ref": commit1}}
+    }).create();
+
+    pubInstall();
+
+    // Change the commit in the pubspec.
+    d.appDir({
+      "foo": {"git": {"url": "../foo.git", "ref": commit2}}
+    }).create();
+
+    startPubServe(shouldInstallFirst: true);
+    requestShouldSucceed("packages/foo/foo.dart", 'main() => "after";');
+    endPubServe();
+  });
+}