Slow Rails 7.x test suite

sentry-rails/spec/dummy/test_rails_app/app.rb

@@ -10,6 +10,7 @@
 require "action_controller/railtie"
 
 require 'sentry/rails'
+require 'tempfile'
 
 ActiveRecord::Base.logger = Logger.new(nil)
 ActiveRecord::Base.establish_connection(adapter: "sqlite3", database: "db")
@@ -43,70 +44,115 @@ class TestApp < Rails::Application
 require "dummy/test_rails_app/configs/#{FILE_NAME}"
 
 def make_basic_app(&block)
-  run_pre_initialize_cleanup
+  elapsed("pre_initialize_cleanup") do
+    run_pre_initialize_cleanup
+  end
+
+  app = nil
 
-  app = Class.new(TestApp) do
-    def self.name
-      "RailsTestApp"
+  elapsed("app_setup") do
+    app = Class.new(TestApp) do
+      def self.name
+        "RailsTestApp"
+      end
     end
   end
 
-  app.config.active_support.deprecation = :silence
-  app.config.action_controller.view_paths = "spec/dummy/test_rails_app"
-  app.config.hosts = nil
-  app.config.secret_key_base = "test"
-  app.config.logger = ActiveSupport::Logger.new(nil)
-  app.config.eager_load = true
-  app.config.active_job.queue_adapter = :test
+  elapsed("app_config") do
+    app.config.active_support.deprecation = :silence
+    app.config.action_controller.view_paths = "spec/dummy/test_rails_app"
+    app.config.hosts = nil
+    app.config.secret_key_base = "test"
+    app.config.logger = ActiveSupport::Logger.new(nil)
+    app.config.eager_load = true
+    app.config.active_job.queue_adapter = :test
+  end
 
   # Eager load namespaces can be accumulated after repeated initializations and make initialization
   # slower after each run
   # This is especially obvious in Rails 7.2, because of https://github.com/rails/rails/pull/49987, but other constants's
   # accumulation can also cause slowdown
   # Because this is not necessary for the test, we can simply clear it here
-  app.config.eager_load_namespaces.clear
-
-  configure_app(app)
-
-  app.routes.append do
-    get "/exception", to: "hello#exception"
-    get "/view_exception", to: "hello#view_exception"
-    get "/view", to: "hello#view"
-    get "/not_found", to: "hello#not_found"
-    get "/world", to: "hello#world"
-    get "/with_custom_instrumentation", to: "hello#with_custom_instrumentation"
-    resources :posts, only: [:index, :show] do
-      member do
-        get :attach
+  elapsed("eager_load_namespaces_clear") do
+    app.config.eager_load_namespaces.clear
+  end
+
+  elapsed("configure_app") do
+    configure_app(app)
+  end
+
+  elapsed("routes_append") do
+    app.routes.append do
+      get "/exception", to: "hello#exception"
+      get "/view_exception", to: "hello#view_exception"
+      get "/view", to: "hello#view"
+      get "/not_found", to: "hello#not_found"
+      get "/world", to: "hello#world"
+      get "/with_custom_instrumentation", to: "hello#with_custom_instrumentation"
+      resources :posts, only: [:index, :show] do
+        member do
+          get :attach
+        end
       end
+      get "500", to: "hello#reporting"
+      root to: "hello#world"
     end
-    get "500", to: "hello#reporting"
-    root to: "hello#world"
   end
 
-  app.initializer :configure_sentry do
-    Sentry.init do |config|
-      config.release = 'beta'
-      config.dsn = "http://12345:[email protected]:3000/sentry/42"
-      config.transport.transport_class = Sentry::DummyTransport
-      # for sending events synchronously
-      config.background_worker_threads = 0
-      config.capture_exception_frame_locals = true
-      yield(config, app) if block_given?
+  elapsed("sentry_init") do
+    app.initializer :configure_sentry do
+      Sentry.init do |config|
+        config.release = 'beta'
+        config.dsn = "http://12345:[email protected]:3000/sentry/42"
+        config.transport.transport_class = Sentry::DummyTransport
+        # for sending events synchronously
+        config.background_worker_threads = 0
+        config.capture_exception_frame_locals = true
+        yield(config, app) if block_given?
+      end
     end
   end
 
-  app.initialize!
+  elapsed("initialize") do
+    app.initialize!
+  end
 
-  Rails.application = app
+  elapsed("rails_application_set") do
+    Rails.application = app
+  end
 
-  # load application code for the Rails version
-  require "dummy/test_rails_app/apps/#{FILE_NAME}"
+  elapsed("require_app_code") do
+    # load application code for the Rails version
+    require "dummy/test_rails_app/apps/#{FILE_NAME}"
+  end
 
-  Post.all.to_a # to run the sqlte version query first
+  elapsed("post_all") do
+    Post.all.to_a # to run the sqlte version query first
+  end
 
-  # and then clear breadcrumbs in case the above query is recorded
-  Sentry.get_current_scope.clear_breadcrumbs if Sentry.initialized?
+  elapsed("clear_breadcrumbs") do
+    # and then clear breadcrumbs in case the above query is recorded
+    Sentry.get_current_scope.clear_breadcrumbs if Sentry.initialized?
+  end
+
+  puts "\nElapsed Time Summary:\n\n"
+  RECORDED_ELAPSED.each do |label, total|
+    puts "#{label}: %.8f seconds" % total
+  end
+  puts "\n" + "*" * 80
+  puts "\nTotal Elapsed Time: %.8f seconds\n" % RECORDED_ELAPSED.values.sum
+  puts "\n" + "*" * 80
 
   app
 end
+
+def elapsed(label)
+  start = Process.clock_gettime(Process::CLOCK_MONOTONIC, :nanosecond)
+  yield
+  stop = Process.clock_gettime(Process::CLOCK_MONOTONIC, :nanosecond)
+  elapsed = (stop - start) / 1_000_000_000.0
+  RECORDED_ELAPSED[label] += elapsed
+  elapsed
+end
+
+RECORDED_ELAPSED = Hash.new { |h, k| h[k] = 0 }