Why is RSpec so slow under Rails?

Question

Whenever I run rspec tests for my Rails application it takes forever and a day of overhead before it actually starts running tests. Why is rspec so slow? Is there a way to

Answer 1

You should be able to to speed up your script/spec calls by running script/spec_server in a separate terminal window, then adding the additional -X parameter to your spec calls.

Answer 2

because it loads all the environement, loads fixtures and all that jazz.

The real culprit is if you run it using rake spec, it runs the db:test:prepare task.

This task drops your entire test database and re-creates it from scratch. This seems ridiculous to me, but that's what it does (the same thing happens when you run rake:test:units etc).

You can easily work around this using the spec application which rspec installs as part of the rspec gem.

Like this:

cd railsapp
spec spec # run all specs without rebuilding the whole damn database
spec spec/models # run model specs only

cd spec
spec controllers/user* # run specs for controllers that start with user

Answer 3

If you're using a Mac I recommend using Rspactor over autotest as it uses a lot fewer resources for polling changed files than autotest. There is both a full Cocoa version

RSpactor.app

or the gem version that I maintain at Github

sudo gem install pelle-rspactor

While these don't speed up individual rspec tests, they feel much faster as they auto run the affected spec's within a second of you hitting save.

Answer 4

I think the "zen" experience you're looking for is to run spec_server and autospec in the background, with the result being near-instant tests when you save a file.

However, I'm having problems getting these two programs to communicate.

I found an explanation here:

I've noticed that autotest doesn't send commands to the spec_server. Instead it reloads the entire Rails environment and your application's plugins everytime it executes. This causes autotest to run significantly slower than script server, because when you run the script/spec command the specs are sent to the spec_server which already has your Rails environment fired up and ready to go. If you happen to install a new plugin or something like that, then you'll have to restart the spec_server.

But, how do we fix this issue? I'm guessing it would involve downloading ZenTest and changing code for the autotest program, but don't have time to try it out right now.

Answer 5

Why is rspec so slow? because it loads all the environement, loads fixtures and all that jazz.

Is there a way to speed up Rails' initial load you could try using mocks instead of relying on the database, this is actually correct for unit testing and will definitly speed up your unit tests. Additionnaly using the spec server as mentionned by @Scott Matthewman can help, same with the autotest from zentest mentionned by @Marc-Andre Lafortune

Is there a way to single out the part of my Rails app I need (e.g. ActiveRecord stuff only) so it doesn't load absolutely everything to run a few tests? what about this

rake test:recent 

I am not sure how the rspec task integrate with this but you could definitely use the test:recent task as a template to do the same with rspec tests if the.

rake test:rspec:recent

doesn't exist yet

Answer 6

Are you running this over Rails? If so, it's not RSpec's initialization that's slow, it's Rails'. Rails has to initialize the entire codebase and yours before running the specs. Well, it doesn't have to, but it does. RSpec runs pretty fast for me under my small non-rails projects.