seed_fixtures

Use your seeds.rb as fixtures when running tests.

Read the back story of this gem: https://ghiculescu.substack.com/p/using-realistic-development-and-test

Currently only Rails 7 is supported. PRs to support older Rails versions are welcome!

Quick start

1. Add seed_fixtures to the test group of your Gemfile, then run bundle install.

2. In your test_helper.rb:

class ActiveSupport::TestCase
  # Add this line:
  fixtures_from_seeds

  # Comment out or remove this line:
  # fixtures :all
end

Notes:

• You cannot use standard Rails fixtures if you are using this gem. Make sure you remove the fixtures call that's included in test_helper.rb by default!
• Ensure your test_helper.rb includes this: require "rails/test_help".

3. Add .seeds_hash to your .gitignore file.

What it does

• When tests run, the contents of db/seeds.rb will be loaded into the test database.
• To improve performance, keeps a hash of everything your app's db/ folder in the .seeds_hash file. This way, seeds are only reloaded into the database if you change your seeds file or your schema.
• Adds a parallel_setup hook, so if you run parallel tests, seeds will be loaded correctly. (This is needed because parallel databases are truncated before each run.)

How do I access seed data in my test?

Just like anything else in the database...

user = User.find_by(name: "Alex")

Or if you like, define helper methods for easy lookup.

module SeedFixtureLookups
  def user_alex
    @user_alex ||= User.where(name: "Alex").sole
  end
end

class ActiveSupport::TestCase
  include SeedFixtureLookups
end

# in a test...
test "alex exists" do
  assert_not_nil user_alex
end

I thought seeds are for development, not testing!?

Not everyone agrees this is a good idea. And for many apps, it's not! But for some apps it is a very neat way of writing a robust test suite. If your app is one of those, give this a try.

There's more back story on the gem here: https://ghiculescu.substack.com/p/using-realistic-development-and-test

License

The gem is available as open source under the terms of the MIT License.