1 files changed, 19 insertions, 0 deletions
diff --git a/actionpack/test/dispatch/debug_exceptions_test.rb b/actionpack/test/dispatch/debug_exceptions_test.rb
index 5ae8a20ae4..3e57e8f4d9 100644
--- a/actionpack/test/dispatch/debug_exceptions_test.rb
+++ b/actionpack/test/dispatch/debug_exceptions_test.rb
@@ -620,4 +620,23 @@ class DebugExceptionsTest < ActionDispatch::IntegrationTest
       assert_select 'input[value="Action 2"]'
     end
   end
+
+  test "debug exceptions app shows diagnostics when malformed query parameters are provided" do
+    @app = DevelopmentApp
+
+    get "/bad_request?x[y]=1&x[y][][w]=2"
+
+    assert_response 400
+    assert_match "ActionController::BadRequest", body
+  end
+
+  test "debug exceptions app shows diagnostics when malformed query parameters are provided by XHR" do
+    @app = DevelopmentApp
+    xhr_request_env = { "action_dispatch.show_exceptions" => true, "HTTP_X_REQUESTED_WITH" => "XMLHttpRequest" }
+
+    get "/bad_request?x[y]=1&x[y][][w]=2", headers: xhr_request_env
+
+    assert_response 400
+    assert_match "ActionController::BadRequest", body
+  end
 end