fixture_bot
Improve the performance of your tests, as factories generate and insert data into the database every time, it can be slow. See benchmarks.
Problems using Rails fixtures:
- No data validation
- Long loading of fixtures (for one or all tests - equally long)
- YML format (no reuse code)
- heavy support for fixtures and factories together
Installation
group :test do
gem "factory_bot"
gem "fixture_bot", require: false
end
Usage
To define your fixture in factories, use the preload
method
FactoryBot.define do
factory :user do
name "John Doe"
sequence(:email) {|n| "john#{n}@example.org" }
end
preload(:users) do
fixture_with_id(:first) { create(:user, id: 1) }
fixture(:john) { create(:user) }
fixture(:with_gmail) { create(:user, email: "email@gmail.com") }
end
end
FactoryBot.define do
factory :projects do
name "My Project"
user { users(:with_gmail) }
end
preload(:users) do
fixture(:myapp) { create(:project, user: users(:john)) }
end
end
RSpec usage
require "spec_helper"
describe User do
let(:user) { users(:john) }
it "returns john's record" do
expect(users(:john)).to be_a User
end
it "returns myapp's record" do
expect(projects(:myapp).user).to eq users(:john)
end
it "each call fixture return new object" do
expect(user.object_id).not_to eq users(:john).object_id
end
end
RSpec Setup
On your spec/support/factory_bot.rb
file
require "fixture_bot" # the order is important, it must be before loaded factories
require "factory_bot_rails"
FactoryBot::SyntaxRunner.class_eval do
include RSpec::Mocks::ExampleMethods
end
RSpec.configure do |config|
config.include FactoryBot::Syntax::Methods
end
Minitest Setup
On your test/test_helper.rb
file, make sure that transaction fixtures are
enabled. Here's what your file may look like
# First, load fixture_bot
require "fixture_bot"
FixtureBot.minitest
require "test_helper"
class UserTest < ActiveSupport::TestCase
test "returns john's record" do
assert_instance_of User, users(:john)
end
test "returns myapp's record" do
assert_equal users(:john), projects(:myapp).user
end
end
Callbacks
FixtureBot.after_load_fixtures do
# code uses fixtures
end
Benchmarks
factories vs fixtures
# simple model with 10 fields
Benchmark.ips do |x|
x.report("fixture") { brands(:lux) }. # fixture: 4666.2 i/s
x.report("factory") { create(:brand) } # factory: 1077.8 i/s - 4.33x slower
x.compare!
end
# user model with 40+ fields, 1 association
Benchmark.ips do |x|
x.report("fixture") { users(:with_post_index)} # fixture: 3395.4 i/s
x.report("factory") { create(:user) } # factory: 159.6 i/s - 21.27x slower
x.compare!
end
# product model with 40+ fields, 5+ associations
Benchmark.ips do |x|
x.report("fixture") { products(:available) } # fixture: 3564.3 i/s
x.report("factory") { create(:product, :available) } # factory: 67.7 i/s - 52.68x slower
x.compare!
end
License
The gem is available as open source under the terms of the MIT License.