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Write-once read-only fixtures for Rails tests

In the project I’m currently working on, I’m heavily using factory_girl to generate test data, rather than using the old Rails fixtures standby. However, I still have a set of read-only fixtures (which are used for testing read-only models against a legacy database). I’m using these in my tests, but since they are read only (like, seriously - the models are marked as by using after_find to call readonly!, ensuring that records will not be accidentally written), there’s no need to wipe and re-insert them per-test.

It’s not too hard to set up fixtures to be inserted once per test suite run –

In your test_helper.rb, above the class ActiveSupport::TestCase definition, add the following:

Fixtures.reset_cache
fixtures_folder = File.join(RAILS_ROOT, 'test', 'fixtures')
fixtures = Dir[File.join(fixtures_folder, '*.yml')].map {|f| File.basename(f, '.yml') }
Fixtures.create_fixtures(fixtures_folder, fixtures)
Fixtures.reset_cache

Next, turn off transactional fixtures and comment out the fixtures macro:

self.use_transactional_fixtures = false
# fixtures :all

That’s all there is to it. Your fixtures will be inserted into your test database once when test_helper is included for the first time, and then not again for the rest of the test suite run. This should speed your tests up substantially.

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