1 files changed, 10 insertions, 0 deletions
diff --git a/actionpack/test/dispatch/middleware_stack_test.rb b/actionpack/test/dispatch/middleware_stack_test.rb
index 170c5b8565..6a1a4f556f 100644
--- a/actionpack/test/dispatch/middleware_stack_test.rb
+++ b/actionpack/test/dispatch/middleware_stack_test.rb
@@ -66,6 +66,16 @@ class MiddlewareStackTest < ActiveSupport::TestCase
     assert_equal BazMiddleware, @stack[0].klass
   end
 
+  test "raise an error on invalid index" do
+    assert_raise RuntimeError do
+      @stack.insert("HiyaMiddleware", BazMiddleware)
+    end
+
+    assert_raise RuntimeError do
+      @stack.insert_after("HiyaMiddleware", BazMiddleware)
+    end
+  end
+
   test "lazy evaluates middleware class" do
     assert_difference "@stack.size" do
       @stack.use "MiddlewareStackTest::BazMiddleware"