Make sure pub build/serve get at the right time:

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

Index: sdk/lib/_internal/pub/test/serve/gets_first_if_dependency_is_not_installed_test.dart
diff --git a/sdk/lib/_internal/pub/test/serve/watch_removed_file_test.dart b/sdk/lib/_internal/pub/test/serve/gets_first_if_dependency_is_not_installed_test.dart
similarity index 51%
copy from sdk/lib/_internal/pub/test/serve/watch_removed_file_test.dart
copy to sdk/lib/_internal/pub/test/serve/gets_first_if_dependency_is_not_installed_test.dart
index 55ff576d655fb58ac7ce09318a3465a6aee83840..8926faf6ecbd18106ea801b4503cb061aa39e942 100644
--- a/sdk/lib/_internal/pub/test/serve/watch_removed_file_test.dart
+++ b/sdk/lib/_internal/pub/test/serve/gets_first_if_dependency_is_not_installed_test.dart
@@ -14,22 +14,19 @@ import 'utils.dart';
 
 main() {
   initConfig();
-  integration("stop serving a file that is removed", () {
-    d.dir(appPath, [
-      d.appPubspec(),
-      d.dir("web", [
-        d.file("index.html", "body")
-      ])
-    ]).create();
-
-    pubServe();
-    requestShouldSucceed("index.html", "body");
-
-    schedule(() => deleteEntry(
-        path.join(sandboxDir, appPath, "web", "index.html")));
-
-    waitForBuildSuccess();
-    requestShould404("index.html");
+  integration("gets first if a dependency is not installed", () {
+    servePackages([packageMap("foo", "1.2.3")]);
+
+    d.appDir({"foo": "1.2.3"}).create();
+
+    // Run pub to get a lock file.
+    pubGet();
+
+    // Delete the system cache so it isn't installed any more.
+    schedule(() => deleteEntry(path.join(sandboxDir, cachePath)));
+
+    pubServe(shouldGetFirst: true, numDownloads: 1);
+    requestShouldSucceed("packages/foo/foo.dart", 'main() => "foo 1.2.3";');
     endPubServe();
   });
 }