1 files changed, 68 insertions, 0 deletions
diff --git a/spec/lib/gitlab/exceptions_app_spec.rb b/spec/lib/gitlab/exceptions_app_spec.rb
new file mode 100644
index 00000000000..6b726a044a8
--- /dev/null
+++ b/spec/lib/gitlab/exceptions_app_spec.rb
@@ -0,0 +1,68 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Gitlab::ExceptionsApp, type: :request do
+  describe '.call' do
+    let(:exceptions_app) { described_class.new(Rails.public_path) }
+    let(:app) { ActionDispatch::ShowExceptions.new(error_raiser, exceptions_app) }
+
+    before do
+      @app = app
+    end
+
+    context 'for a 500 error' do
+      let(:error_raiser) { proc { raise 'an unhandled error' } }
+
+      context 'for an HTML request' do
+        it 'fills in the request ID' do
+          get '/', env: { 'action_dispatch.request_id' => 'foo' }
+
+          expect(response).to have_gitlab_http_status(:internal_server_error)
+          expect(response).to have_header('X-Gitlab-Custom-Error')
+          expect(response.body).to include('Request ID: <code>foo</code>')
+        end
+
+        it 'HTML-escapes the request ID' do
+          get '/', env: { 'action_dispatch.request_id' => '<b>foo</b>' }
+
+          expect(response).to have_gitlab_http_status(:internal_server_error)
+          expect(response).to have_header('X-Gitlab-Custom-Error')
+          expect(response.body).to include('Request ID: <code>&lt;b&gt;foo&lt;/b&gt;</code>')
+        end
+
+        it 'returns an empty 500 when the 500.html page cannot be found' do
+          allow(File).to receive(:exist?).and_return(false)
+
+          get '/', env: { 'action_dispatch.request_id' => 'foo' }
+
+          expect(response).to have_gitlab_http_status(:internal_server_error)
+          expect(response).not_to have_header('X-Gitlab-Custom-Error')
+          expect(response.body).to be_empty
+        end
+      end
+
+      context 'for a JSON request' do
+        it 'does not include the request ID' do
+          get '/', env: { 'action_dispatch.request_id' => 'foo' }, as: :json
+
+          expect(response).to have_gitlab_http_status(:internal_server_error)
+          expect(response).not_to have_header('X-Gitlab-Custom-Error')
+          expect(response.body).not_to include('foo')
+        end
+      end
+    end
+
+    context 'for a 404 error' do
+      let(:error_raiser) { proc { raise AbstractController::ActionNotFound } }
+
+      it 'returns a 404 response that does not include the request ID' do
+        get '/', env: { 'action_dispatch.request_id' => 'foo' }
+
+        expect(response).to have_gitlab_http_status(:not_found)
+        expect(response).not_to have_header('X-Gitlab-Custom-Error')
+        expect(response.body).not_to include('foo')
+      end
+    end
+  end
+end