Install before starting the server if the lockfile is out of date.

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

Index: sdk/lib/_internal/pub/test/serve/does_not_install_first_if_git_url_did_not_change_test.dart
diff --git a/sdk/lib/_internal/pub/test/serve/unknown_dependency_test.dart b/sdk/lib/_internal/pub/test/serve/does_not_install_first_if_git_url_did_not_change_test.dart
similarity index 50%
copy from sdk/lib/_internal/pub/test/serve/unknown_dependency_test.dart
copy to sdk/lib/_internal/pub/test/serve/does_not_install_first_if_git_url_did_not_change_test.dart
index 434a84ccfb032f54cae1b11fcfd263800789f3e4..ee92c92f7ca14ef97cbd935a5f31423ee9eda393 100644
--- a/sdk/lib/_internal/pub/test/serve/unknown_dependency_test.dart
+++ b/sdk/lib/_internal/pub/test/serve/does_not_install_first_if_git_url_did_not_change_test.dart
@@ -5,6 +5,7 @@
 library pub_tests;
 
 import 'dart:io';
+import 'dart:json' as json;
 
 import '../descriptor.dart' as d;
 import '../test_pub.dart';
@@ -12,16 +13,20 @@ import 'utils.dart';
 
 main() {
   initConfig();
-  integration("responds with a 404 unknown dependencies", () {
-    d.dir(appPath, [
-      d.appPubspec()
+  integration("does not install first if a git dependency's url is "
+      "unchanged", () {
+    d.git('foo.git', [
+      d.libPubspec('foo', '1.0.0'),
+      d.libDir("foo")
     ]).create();
 
-    startPubServe();
-    requestShould404("packages/foo/nope.dart");
-    requestShould404("assets/foo/nope.png");
-    requestShould404("dir/packages/foo/nope.dart");
-    requestShould404("dir/assets/foo/nope.png");
+    d.appDir({
+      "foo": {"git": "../foo.git"}
+    }).create();
+
+    pubInstall();
+    startPubServe(shouldInstallFirst: false);
+    requestShouldSucceed("packages/foo/foo.dart", 'main() => "foo";');
     endPubServe();
   });
 }