diff --git a/example/pubspec.yaml b/example/pubspec.yaml
index 5227e47ed..cb53d3782 100644
--- a/example/pubspec.yaml
+++ b/example/pubspec.yaml
@@ -8,5 +8,5 @@ dependencies:
   angular: ^5.0.0-alpha+10
 
 dev_dependencies:
-  build_runner: ^0.8.2
+  build_runner: ^0.8.5
   build_web_compilers: ^0.3.6
diff --git a/webdev/test/e2e_test.dart b/webdev/test/e2e_test.dart
index ae0adde50..2e0ebc1a5 100644
--- a/webdev/test/e2e_test.dart
+++ b/webdev/test/e2e_test.dart
@@ -53,6 +53,14 @@ void main() {
         process.stdout,
         emitsThrough(
             '[WARNING] Skipped creation of the merged output directory.'));
+
+    await expectLater(
+        process.stderr,
+        emitsThrough(
+            '[SEVERE] Unable to create merged directory for ${d.sandbox}. '
+            'Choose a different directory or delete the contents of that '
+            'directory'));
+
     await expectLater(process.stderr,
         emitsThrough('Failed to create merged output directories.'));