Add a test to make sure there's no XSS for hook logs

spec/features/projects/hook_logs/user_reads_log_spec.rb

+require 'spec_helper'
+
+feature 'Hook logs' do
+  given(:web_hook_log) { create(:web_hook_log, response_body: '<script>') }
+  given(:project) { web_hook_log.web_hook.project }
+  given(:user) { create(:user) }
+
+  before do
+    project.add_master(user)
+
+    sign_in(user)
+  end
+
+  scenario 'user reads log without getting XSS' do
+    visit(
+      project_hook_hook_log_path(
+        project, web_hook_log.web_hook, web_hook_log))
+
+    expect(page).to have_content('<script>')
+  end
+end