FixtureBuilder
Based on the code from fixture_scenarios, by Chris Wanstrath. Allows you to build file fixtures from existing object mother factories, like FactoryGirl, to generate high performance fixtures that can be shared across all your tests and development environment.
The best of all worlds!
- Speed: Leverage the high-performance speed of Rails' transactional tests/fixtures to avoid test suite slowdown as your app's number of tests grows, because creating and persisting data is slow!
- Maintainability/Reuse/Abstraction: Use object mother factories to generate fixtures via FactoryGirl or your favorite tool
- Flexibility: You can always fall back to object mothers in tests if needed, or load a fixture and modify only an attribute or two without the overhead of creating an entire object dependency graph.
- Consistency: Use the exact same fixture data in all environments: test, development, and demo/staging servers. Makes reproduction and acceptance testing of bugs/features faster and easier!
- Simplicity: Avoid having to maintain and generate
seeds.rb
sample data set separately from your test fixture/factory data set, or pick which of the myriad seeds helper gems to use. Just deleteseeds.rb
and forget about it!
Installing
Install:
- Directly:
gem install fixture_builder
- Bundler:
# Gemfile group :development, :test do gem 'fixture_builder'
- Directly:
Create a file which configures and declares your fixtures (see below for examples)
Require the above file in your
spec_helper.rb
ortest_helper.rb
If you are using rspec, ensure you have
- Set the
FIXTURES_PATH
inconfig/application.rb
(not test.rb, or you can't userake db:fixtures:load
). E.g.:
module MyApp class Application < Rails::Application #... ENV['FIXTURES_PATH'] = 'spec/fixtures' #...
- Set
config.fixture_path = Rails.root.join('spec/fixtures')
inspec/rails_helper.rb
- Set
config.global_fixtures = :all
if you don't want to specify fixtures in every spec file.
- Set the
You probably also want to use config.use_transactional_fixtures (if you are using rspec) or use_transactional_fixtures/use_transactional_tests (if you are not using rspec),
If you are using fixtures in Selenium-based Capybara/Cucumber specs that runs the tests and server in separate processes, you probably want to consider setting transactional fixtures to false, and instead using Database Cleaner with
DatabaseCleaner.strategy = :truncation
orDatabaseCleaner.strategy = :deletion
.
Usage
- When running tests/specs, fixtures will build/rebuild automatically as needed
rake spec:fixture_builder:build
to force a build of fixturesrake spec:fixture_builder:clean
to delete all existing fixture filesrake spec:fixture_builder:rebuild
to force a rebuild of fixtures (just a clean + build)rake db:fixtures:load
to load built fixtures into your development environment (this is a standard Rails rake task)
Configuration Example
spec/rails_helper.rb
or test/test_helper.rb
:
require_relative 'support/fixture_builder'
When using an object mother such as factory_girl it can be setup like the following:
# spec/support/fixture_builder.rb
FixtureBuilder.configure do |fbuilder|
# rebuild fixtures automatically when these files change:
fbuilder.files_to_check += Dir["spec/factories/*.rb", "spec/support/fixture_builder.rb"]
# now declare objects
fbuilder.factory do
david = Factory(:user, :unique_name => "david")
ipod = Factory(:product, :name => "iPod")
Factory(:purchase, :user => david, :product => ipod)
end
end
The block passed to the factory method initiates the creation of the fixture files. Before yielding to the block, FixtureBuilder cleans out the test database completely. When the block finishes, it dumps the state of the database into fixtures, like this:
# users.yml
david:
created_at: 2010-09-18 17:21:23.926511 Z
unique_name: david
id: 1
# products.yml
i_pod:
name: iPod
id: 1
# purchases.yml
purchase_001:
product_id: 1
user_id: 1
FixtureBuilder guesses about how to name fixtures based on a prioritized list of attribute names.
You can also hint at a name or manually name an object. Both of the following lines would
work to rename purchase_001
to davids_ipod
:
fbuilder.name(:davids_ipod, Factory(:purchase, :user => david, :product => ipod))
@davids_ipod = Factory(:purchase, :user => david, :product => ipod)
Another way to name fixtures is to use the name_model_with. To use it you create a block that returns how you want a certain model name based on the record field.
fbuilder.name_model_with(User) do |record|
[record['first_name'], record['last_name']].join('_')
end
For all User fixture 'foo', last_name: 'bar' it would generate foo_bar
as the fixture name.
There are also additional configuration options that can be changed to override the defaults:
- files_to_check: array of filenames that when changed cause fixtures to be rebuilt
- fixture_builder_file: the pathname of the file used to store file changes.
- record_name_fields: array of field names to use as a fixture's name prefix, it will use the first matching field it finds
- skip_tables: array of table names to skip building fixtures
- select_sql: sql string to use for select
- delete_sql: sql string to use for deletes
By default these are set as:
- files_to_check: %w{ db/schema.rb }
- fixture_builder_file: RAILS_ROOT/tmp/fixture_builder.yml
- record_name_fields: %w{ unique_name display_name name title username login }
- skip_tables: %w{ schema_migrations }
- select_sql: SELECT * FROM %table
- delete_sql: DELETE FROM %table
Sequence Collisions
One problem with generating your fixtures is that sequences can collide. When the fixtures are generated only as needed, sometimes the process that generates the fixtures will be different than the process that runs the tests. This results in collisions when you still use factories in your tests.
There's a couple of solutions for this.
Here's a solution for FactoryGirl which resets sequences numbers to 1000 (to avoid conflicts with fixture data which should be sequenced < 1000) before the tests run:
FixtureBuilder.configure do |fbuilder|
# ...
end
# Have factory girl generate non-colliding sequences starting at 1000 for data created after the fixtures
# Factory Girl <2 yields name & seq
# Factory Girl >2 yeilds only seq
FactoryGirl.sequences.each do |seq|
# Factory Girl 4 uses an Enumerator Adapter, otherwise simply set a Fixnum
seq.instance_variable_set(:@value, FactoryGirl::Sequence::EnumeratorAdapter.new(1000))
end
Another solution is to explicitly reset the database primary key sequence via ActiveRecord.
You could call this method before you run your factories in the fixture_builder.rb
block:
def reset_pk_sequences
puts 'Resetting Primary Key sequences'
ActiveRecord::Base.connection.tables.each do |t|
ActiveRecord::Base.connection.reset_pk_sequence!(t)
end
end
It's probably a good idea to use both of these approaches together, especially if you are going to fall back to using FactoryGirl object mothers in addition to fixtures.
Tips
- Don't use
seeds.rb
(just delete it). Instead, just userake db:fixtures:load
to get fixtures into dev. - If you want fixture data on a staging/demo environment, either run
db:fixtures:load
on that environment, or load fixtures into the dev withrake db:fixtures:load
, dump the dev database, then load it on your environment. - Always use fixtures instead of object mothers in tests when possible - this will keep your test suite fast! Even FactoryGirl says to avoid using factories when you can, because creating and persisting data is slow
- If you only need to tweak an attribute or two to test an edge case, load the fixture object,
then just set the attribute on the object (if you don't need it persisted, this is fastest), or
set it via
#update_attributes!
(only if you need it persisted, this is slower). - Avoid referring to any fixtures by ID anywhere, unless you hardcode the ID when creating it. They can change if you add more fixtures in the future and cause tests to break.
- To set up associations between different types of created fixture model objects, you can
use a couple of approaches:
- When creating fixtures, keep a hash of all created models by type + name (not ID), and then look them up out of the hash to use as an associated object when creating subsequent related objects.
- Do a
MyModel.find_by_some_unique_field
to find a previously created instance that didn't have a name.
- If you delete a table, old fixture files for the deleted table can hang around and still get loaded
into the database, causing confusion or errors. Use
rake spec:fixture_builder:clean
orrake spec:fixture_builder:rebuild
to ensure they get cleaned up. - As you build more advanced fixture creation logic for your app's domain and try to DRY it up, you'll probably
end up having an easier time if:
- You don't use any namespaced models
- You keep your factory names consistent and exactly matching your model names
Modify
bin/setup
to run fixture builder and load your dev database:puts "\n== Building fixtures ==" system! 'bin/rails spec:fixture_builder:rebuild' puts "\n== Loading fixtures into dev database ==" system! 'bin/rails db:fixtures:load'
More Complete Config Example
As you get more fixtures, you may want to move the creation of fixtures to a separate file. For example:
# spec/support/fixture_builder.rb
require_relative 'create_fixtures'
FixtureBuilder.configure do |fbuilder|
# rebuild fixtures automatically when these files change:
fbuilder.files_to_check += Dir[
"spec/factories/*.rb",
"spec/support/fixture_builder.rb",
"spec/support/create_fixtures.rb",
]
# now declare objects
fbuilder.factory do
CreateFixtures.new(fbuilder).create_all
end
end
# Have factory girl generate non-colliding sequences starting at 1000 for data created after the fixtures
FactoryGirl.sequences.each do |seq|
seq.instance_variable_set(:@value, FactoryGirl::Sequence::EnumeratorAdapter.new(1000))
end
Then, you can do more extensive and advanced fixture creation in that class. Here's a partial example:
# spec/support/create_fixtures.rb
require 'factory_girl_rails'
class CreateFixtures
include FactoryGirl::Syntax::Methods
attr_accessor :fbuilder, :models, :fixed_time
def initialize(fbuilder)
@fbuilder = fbuilder
@models = {}
@fixed_time = Time.utc(2015, 3, 14, 9, 2, 6)
end
def create_all
reset_pk_sequences
create_users
create_products
create_purchases
reset_pk_sequences
end
private
def reset_pk_sequences
puts 'Resetting Primary Key sequences'
ActiveRecord::Base.connection.tables.each do |t|
ActiveRecord::Base.connection.reset_pk_sequence!(t)
end
end
def create_users
# etc...
end
# other creation and helper methods to abstract common logic, e.g.
# * custom naming rules via #name_model_with
# * set up associations by storing created model records in a hash so you can retrieve them
# etc... (hopefully some of these helper patterns can be standardized and included in the gem in the future)
end
Copyright (c) 2009 Ryan Dy & David Stevenson, released under the MIT license
Currently maintained by Chad Woolley