FixtureFarm

This gem lets you do two things:

• record fixtures as you browse.
• record fixtures for a block of code (e.g. setup part of a test).

Generated fixture that belongs_to a record from an existing fixture, will reference that fixture by name.

Limitations

• doesn't update fixtures
• doesn't delete fixtures
• assumes that all serialized attributes are json (so that at least ActiveStorage::Blob metadata is correctly represented; it really should be Rails serializing attributes according to their respective coders when inserting fixtures into the database, but, alas, this isn't happening)

Installation

Add this line to your application's Gemfile:

gem 'fixture_farm', group: %i[development test]

And then execute:

bundle install

Or install it yourself as:

gem install fixture_farm

Usage

Record as you browse

To record as you browse in development add this to ApplicationController:

include FixtureFarm::ControllerHook if defined?(FixtureFarm)

And in ApplicationJob if needed:

include FixtureFarm::ActiveJobHook if defined?(FixtureFarm)

Then start/stop recording using tasks:

bundle exec fixture_farm record some_awesome_name_prefix
bundle exec fixture_farm status
bundle exec fixture_farm stop

Record in tests

To record in tests, wrap some code in record_new_fixtures block. For example:

include FixtureFarm::TestHelper

test 'some stuff does the right thing' do
  record_new_fixtures do |stop_recording|
    user = User.create!(name: 'Bob')
    post = user.posts.create!(title: 'Stuff')

    stop_recording.call

    assert_difference 'user.published_posts.size' do
      post.publish!
    end
  end
end

Running this test generates user and post fixtures. Now you can rewrite this test to use them:

test 'some stuff does the right thing' do
  user = users('user_1')

  assert_difference 'user.published_posts.size' do
    user.posts.first.publish!
  end
end

record_new_fixtures accepts optional name prefix, that applies to all new fixture names.

A more robust approach is to have dedicated fixture tests that normally fail, but can be optionally run in "record mode" (think VCR).

For example, let's say we have Author model that has_many :posts and we require authors to have at least one post. Here's the test to enforce authors fixtures to comply with this rule:

test 'authors fixtures must have at least one post' do
  offending_records = Author.where.missing(:posts)

  assert_empty offending_records
end

Let's say this test is currently failing.

Now let's add the option to automatically record missing fixtures:

test 'authors fixtures must have at least one post' do
  offending_records = Author.where.missing(:posts)

  if ENV['RECORD_FIXTURES']
    record_new_fixtures do
      offending_records.each do |author|
        author.posts.create!(text: 'some text')
      end
    end
  end

  assert_empty offending_records
end

Running this test with RECORD_FIXTURES=1 will generate missing fixture entries in test/fixtures/posts.yml. Now re-run the test again and it's passing.

Automatic fixture naming

Generated fixture names are based on the first belongs_to association of the model. E.g., if a new post fixtures belongs_to to a user fixture bob, the name is going to be bob_post_1.

It's possible to lower the priority of given parent assiciations when it comes to naming, so that certain names are only picked when there are no other suitable parent associations. This is useful, for example, to exclude acts_as_tenant association:

FixtureFarm.low_priority_parent_model_for_naming = -> { _1.is_a?(TenantModel) }

License

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