DEV: Add a per-spec timeout (#21648)

spec/rails_helper.rb

@@ -163,6 +163,8 @@ else
   TestProf::LetItBe.configure { |config| config.alias_to :fab!, refind: true }
 end
 
+PER_SPEC_TIMEOUT_SECONDS = 30
+
 RSpec.configure do |config|
   config.fail_fast = ENV["RSPEC_FAIL_FAST"] == "1"
   config.silence_filter_announcements = ENV["RSPEC_SILENCE_FILTER_ANNOUNCEMENTS"] == "1"
@@ -368,6 +370,16 @@ RSpec.configure do |config|
     "DiscourseEvent registrations were not cleaned up"
   end
 
+  if ENV["CI"]
+    config.around do |example|
+      Timeout.timeout(
+        PER_SPEC_TIMEOUT_SECONDS,
+        nil,
+        "Spec timed out after #{PER_SPEC_TIMEOUT_SECONDS} seconds",
+      ) { example.run }
+    end
+  end
+
   config.before :each do
     # This allows DB.transaction_open? to work in tests. See lib/mini_sql_multisite_connection.rb
     DB.test_transaction = ActiveRecord::Base.connection.current_transaction