Install before starting the server if the lockfile is out of date.

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

Index: sdk/lib/_internal/pub/test/serve/installs_first_if_source_changed_test.dart
diff --git a/sdk/lib/_internal/pub/test/serve/installs_first_if_source_changed_test.dart b/sdk/lib/_internal/pub/test/serve/installs_first_if_source_changed_test.dart
new file mode 100644
index 0000000000000000000000000000000000000000..85d0eee5ad59c472f88020c99b1c1730ac06debf
--- /dev/null
+++ b/sdk/lib/_internal/pub/test/serve/installs_first_if_source_changed_test.dart
@@ -0,0 +1,44 @@
+// 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 dependency's source doesn't match the one "
+      "in the lock file", () {
+    d.dir("foo", [
+      d.libPubspec("foo", "0.0.1"),
+      d.libDir("foo")
+    ]).create();
+
+    d.dir(appPath, [
+      // A pubspec with a path source.
+      d.appPubspec({
+        "foo": {"path": "../foo"}
+      }),
+      // A lock file with the hosted source.
+      d.file("pubspec.lock", json.stringify({
+        'packages': {
+          'foo': {
+            'version': '0.0.0',
+            'source': 'hosted',
+            'description': 'foo'
+          }
+        }
+      }))
+    ]).create();
+
+    startPubServe(shouldInstallFirst: true);
+    requestShouldSucceed("packages/foo/foo.dart", 'main() => "foo";');
+    endPubServe();
+  });
+}