1 files changed, 13 insertions, 0 deletions
diff --git a/spec/requests/users_controller_spec.rb b/spec/requests/users_controller_spec.rb
index eefc24f7824..dacc11eece7 100644
--- a/spec/requests/users_controller_spec.rb
+++ b/spec/requests/users_controller_spec.rb
@@ -636,6 +636,8 @@ RSpec.describe UsersController do
   describe 'GET #exists' do
     before do
       sign_in(user)
+
+      allow(::Gitlab::ApplicationRateLimiter).to receive(:throttled?).and_return(false)
     end
 
     context 'when user exists' do
@@ -677,6 +679,17 @@ RSpec.describe UsersController do
         end
       end
     end
+
+    context 'when the rate limit has been reached' do
+      it 'returns status 429 Too Many Requests', :aggregate_failures do
+        ip = '1.2.3.4'
+        expect(::Gitlab::ApplicationRateLimiter).to receive(:throttled?).with(:username_exists, scope: ip).and_return(true)
+
+        get user_exists_url(user.username), env: { 'REMOTE_ADDR': ip }
+
+        expect(response).to have_gitlab_http_status(:too_many_requests)
+      end
+    end
   end
 
   describe '#ensure_canonical_path' do