1 files changed, 9 insertions, 0 deletions
diff --git a/activestorage/test/controllers/previews_controller_test.rb b/activestorage/test/controllers/previews_controller_test.rb
index c3151a710e..704a466160 100644
--- a/activestorage/test/controllers/previews_controller_test.rb
+++ b/activestorage/test/controllers/previews_controller_test.rb
@@ -21,4 +21,13 @@ class ActiveStorage::PreviewsControllerTest < ActionDispatch::IntegrationTest
     assert_equal 77, image.width
     assert_equal 100, image.height
   end
+
+  test "showing preview with invalid signed blob ID" do
+    get rails_blob_preview_url(
+      filename: @blob.filename,
+      signed_blob_id: "invalid",
+      variation_key: ActiveStorage::Variation.encode(resize: "100x100"))
+
+    assert_response :not_found
+  end
 end