# File lib/big_record/fixtures.rb, line 653 def primary_key_name @primary_key_name ||= model_class && model_class.primary_key end
class BigRecordFixtures
Fixtures are a way of organizing data that you want to test against; in short, sample data. They come in 3 flavors:
1. YAML fixtures 2. CSV fixtures 3. Single-file fixtures
YAML fixtures¶ ↑
This type of fixture is in YAML format and the preferred default. YAML is a file format which describes data structures in a non-verbose, human-readable format. It ships with Ruby 1.8.1+.
Unlike single-file fixtures, YAML fixtures are
stored in a single file per model, which are placed in the directory
appointed by Test::Unit::TestCase.fixture_path=(path)
(this is
automatically configured for Rails, so you can just put your files in
<your-rails-app>/test/fixtures/). The fixture file ends with the .yml
file extension (Rails example:
“<your-rails-app>/test/fixtures/web_sites.yml”). The format of a YAML fixture file looks like this:
rubyonrails: id: 1 name: Ruby on Rails url: http://www.rubyonrails.org google: id: 2 name: Google url: http://www.google.com
This YAML fixture file includes two fixtures. Each YAML fixture (ie. record) is given a name and is followed by an indented list of key/value pairs in the “key: value” format. Records are separated by a blank line for your viewing pleasure.
Note that YAML fixtures are unordered. If you want ordered fixtures, use the omap YAML type. See yaml.org/type/omap.html for the specification. You will need ordered fixtures when you have foreign key constraints on keys in the same table. This is commonly needed for tree structures. Example:
--- !omap - parent: id: 1 parent_id: NULL title: Parent - child: id: 2 parent_id: 1 title: Child
CSV fixtures¶ ↑
Fixtures can also be kept in the Comma Separated Value format. Akin to YAML fixtures, CSV fixtures are stored in a single file, but instead end with the .csv file extension (Rails example: “<your-rails-app>/test/fixtures/web_sites.csv”)
The format of this type of fixture file is much more compact than the others, but also a little harder to read by us humans. The first line of the CSV file is a comma-separated list of field names. The rest of the file is then comprised of the actual data (1 per line). Here's an example:
id, name, url 1, Ruby On Rails, http://www.rubyonrails.org 2, Google, http://www.google.com
Should you have a piece of data with a comma character in it, you can place double quotes around that value. If you need to use a double quote character, you must escape it with another double quote.
Another unique attribute of the CSV fixture is that it has no fixture name like the other two formats. Instead, the fixture names are automatically generated by deriving the class name of the fixture file and adding an incrementing number to the end. In our example, the 1st fixture would be called “web_site_1” and the 2nd one would be called “web_site_2”.
Most databases and spreadsheets support exporting to CSV format, so this is a great format for you to choose if you have existing data somewhere already.
Single-file fixtures¶ ↑
This type of fixture was the original format for Active Record that has
since been deprecated in favor of the YAML and CSV
formats. Fixtures for this format are created by placing text files in a
sub-directory (with the name of the model) to the directory appointed by
Test::Unit::TestCase.fixture_path=(path)
(this is
automatically configured for Rails, so you can just put your files in
<your-rails-app>/test/fixtures/<your-model-name>/ – like
<your-rails-app>/test/fixtures/web_sites/ for the WebSite model).
Each text file placed in this directory represents a “record”. Usually these types of fixtures are named without extensions, but if you are on a Windows machine, you might consider adding .txt as the extension. Here's what the above example might look like:
web_sites/google web_sites/yahoo.txt web_sites/ruby-on-rails
The file format of a standard fixture is simple. Each line is a property (or column in db speak) and has the syntax of “name => value”. Here's an example of the ruby-on-rails fixture above:
id => 1 name => Ruby on Rails url => http://www.rubyonrails.org
Using Fixtures¶ ↑
Since fixtures are a testing construct, we use them in our unit and functional tests. There are two ways to use the fixtures, but first let's take a look at a sample unit test:
require 'web_site' class WebSiteTest < Test::Unit::TestCase def test_web_site_count assert_equal 2, WebSite.count end end
As it stands, unless we pre-load the web_site table in our database with two records, this test will fail. Here's the easiest way to add fixtures to the database:
... class WebSiteTest < Test::Unit::TestCase fixtures :web_sites # add more by separating the symbols with commas ...
By adding a “fixtures” method to the test case and passing it a list of symbols (only one is shown here though), we trigger the testing environment to automatically load the appropriate fixtures into the database before each test. To ensure consistent data, the environment deletes the fixtures before running the load.
In addition to being available in the database, the fixtures are also loaded into a hash stored in an instance variable of the test case. It is named after the symbol… so, in our example, there would be a hash available called @web_sites. This is where the “fixture name” comes into play.
On top of that, each record is automatically “found” (using Model.find(id)) and placed in the instance variable of its name. So for the YAML fixtures, we'd get @rubyonrails and @google, which could be interrogated using regular Active Record semantics:
# test if the object created from the fixture data has the same attributes as the data itself def test_find assert_equal @web_sites["rubyonrails"]["name"], @rubyonrails.name end
As seen above, the data hash created from the YAML fixtures would have @web_sites[“url”] return “www.rubyonrails.org” and @web_sites[“name”] would return “Google”. The same fixtures, but loaded from a CSV fixture file, would be accessible via @web_sites[“name”] == “Ruby on Rails” and have the individual fixtures available as instance variables @web_site_1 and @web_site_2.
If you do not wish to use instantiated fixtures (usually for performance reasons) there are two options.
- to completely disable instantiated fixtures: self.use_instantiated_fixtures = false - to keep the fixture instance (@web_sites) available, but do not automatically 'find' each instance: self.use_instantiated_fixtures = :no_instances
Even if auto-instantiated fixtures are disabled, you can still access them by name via special dynamic methods. Each method has the same name as the model, and accepts the name of the fixture to instantiate:
fixtures :web_sites def test_find assert_equal "Ruby on Rails", web_sites(:rubyonrails).name end
Dynamic fixtures with ERb¶ ↑
Some times you don't care about the content of the fixtures as much as you care about the volume. In these cases, you can mix ERb in with your YAML or CSV fixtures to create a bunch of fixtures for load testing, like:
<% for i in 1..1000 %> fix_<%= i %>:
id: <%= i %> name: guy_<%= 1 %>
<% end %>
This will create 1000 very simple YAML fixtures.
Using ERb, you can also inject dynamic values into your fixtures with inserts like <%= Date.today.strftime(“%Y-%m-%d”) %>. This is however a feature to be used with some caution. The point of fixtures are that they're stable units of predictable sample data. If you feel that you need to inject dynamic values, then perhaps you should reexamine whether your application is properly testable. Hence, dynamic values in fixtures are to be considered a code smell.
Transactional fixtures¶ ↑
TestCases can use begin+rollback to isolate their changes to the database instead of having to delete+insert for every test case. They can also turn off auto-instantiation of fixture data since the feature is costly and often unused.
class FooTest < Test::Unit::TestCase self.use_transactional_fixtures = true self.use_instantiated_fixtures = false fixtures :foos def test_godzilla assert !Foo.find(:all).empty? Foo.destroy_all assert Foo.find(:all).empty? end def test_godzilla_aftermath assert !Foo.find(:all).empty? end end
If you preload your test database with all fixture data (probably in the Rakefile task) and use transactional fixtures, then you may omit all fixtures declarations in your test cases since all the data's already there and every case rolls back its changes.
In order to use instantiated fixtures with preloaded data, set
self.pre_loaded_fixtures
to true. This will provide access to
fixture data for every table that has been loaded through fixtures
(depending on the value of use_instantiated_fixtures
)
When not to use transactional fixtures:
1. You're testing whether a transaction works correctly. Nested transactions don't commit until all parent transactions commit, particularly, the fixtures transaction which is begun in setup and rolled back in teardown. Thus, you won't be able to verify the results of your transaction until Active Record supports nested transactions or savepoints (in progress). 2. Your database does not support transactions. Every Active Record database supports transactions except MySQL MyISAM. Use InnoDB, MaxDB, or NDB instead.
Advanced YAML Fixtures¶ ↑
YAML fixtures that don't specify an ID get some extra features:
-
Stable, autogenerated ID's
-
Label references for associations (belongs_to, has_one, has_many)
-
HABTM associations as inline lists
-
Autofilled timestamp columns
-
Fixture label interpolation
-
Support for YAML defaults
Stable, autogenerated ID's¶ ↑
Here, have a monkey fixture:
george: id: 1 name: George the Monkey reginald: id: 2 name: Reginald the Pirate
Each of these fixtures has two unique identifiers: one for the database and one for the humans. Why don't we generate the primary key instead? Hashing each fixture's label yields a consistent ID:
george: # generated id: 503576764 name: George the Monkey reginald: # generated id: 324201669 name: Reginald the Pirate
ActiveRecord looks at the fixture's model class, discovers the correct primary key, and generates it right before inserting the fixture into the database.
The generated ID for a given label is constant, so we can discover any fixture's ID without loading anything, as long as we know the label.
Label references for associations (belongs_to, has_one, has_many)¶ ↑
Specifying foreign keys in fixtures can be very fragile, not to mention difficult to read. Since ActiveRecord can figure out the ID of any fixture from its label, you can specify FK's by label instead of ID.
belongs_to¶ ↑
Let's break out some more monkeys and pirates.
### in pirates.yml reginald: id: 1 name: Reginald the Pirate monkey_id: 1 ### in monkeys.yml george: id: 1 name: George the Monkey pirate_id: 1
Add a few more monkeys and pirates and break this into multiple files, and it gets pretty hard to keep track of what's going on. Let's use labels instead of ID's:
### in pirates.yml reginald: name: Reginald the Pirate monkey: george ### in monkeys.yml george: name: George the Monkey pirate: reginald
Pow! All is made clear. ActiveRecord
reflects on the fixture's model class, finds all the
belongs_to
associations, and allows you to specify a target
label for the association (monkey:
george) rather than a target id for the
FK (monkey_id: 1).
Polymorphic belongs_to¶ ↑
Supporting polymorphic relationships is a little bit more complicated, since ActiveRecord needs to know what type your association is pointing at. Something like this should look familiar:
### in fruit.rb belongs_to :eater, :polymorphic => true ### in fruits.yml apple: id: 1 name: apple eater_id: 1 eater_type: Monkey
Can we do better? You bet!
apple: eater: george (Monkey)
Just provide the polymorphic target type and ActiveRecord will take care of the rest.
has_and_belongs_to_many¶ ↑
Time to give our monkey some fruit.
### in monkeys.yml george: id: 1 name: George the Monkey pirate_id: 1 ### in fruits.yml apple: id: 1 name: apple orange: id: 2 name: orange grape: id: 3 name: grape ### in fruits_monkeys.yml apple_george: fruit_id: 1 monkey_id: 1 orange_george: fruit_id: 2 monkey_id: 1 grape_george: fruit_id: 3 monkey_id: 1
Let's make the HABTM fixture go away.
### in monkeys.yml george: name: George the Monkey pirate: reginald fruits: apple, orange, grape ### in fruits.yml apple: name: apple orange: name: orange grape: name: grape
Zap! No more fruits_monkeys.yml file. We've specified the list of
fruits on George's fixture, but we could've just as easily
specified a list of monkeys on each fruit. As with belongs_to
,
ActiveRecord reflects on the fixture's
model class and discovers the has_and_belongs_to_many
associations.
Autofilled timestamp columns¶ ↑
If your table/model specifies any of ActiveRecord's standard timestamp columns (created_at, created_on, updated_at, updated_on), they will automatically be set to Time.now.
If you've set specific values, they'll be left alone.
Fixture label interpolation¶ ↑
The label of the current fixture is always available as a column value:
geeksomnia: name: Geeksomnia's Account subdomain: $LABEL
Also, sometimes (like when porting older join table fixtures) you'll need to be able to get ahold of the identifier for a given label. ERB to the rescue:
george_reginald: monkey_id: <%= Fixtures.identify(:reginald) %> pirate_id: <%= Fixtures.identify(:george) %>
Support for YAML defaults¶ ↑
You probably already know how to use YAML to set
and reuse defaults in your database.yml
file,. You can use the
same technique in your fixtures:
DEFAULTS: &DEFAULTS created_on: <%= 3.weeks.ago.to_s(:db) %> first: name: Smurf <<: *DEFAULTS second: name: Fraggle <<: *DEFAULTS
Any fixture labeled “DEFAULTS” is safely ignored.
Constants
- DEFAULT_FILTER_RE
Attributes
Public Class Methods
# File lib/big_record/fixtures.rb, line 469 def self.cache_fixtures(connection, fixtures) cache_for_connection(connection).update(fixtures.index_by(&:table_name)) end
# File lib/big_record/fixtures.rb, line 451 def self.cache_for_connection(connection) @@all_cached_big_record_fixtures[connection.object_id] ||= {} @@all_cached_big_record_fixtures[connection.object_id] end
# File lib/big_record/fixtures.rb, line 460 def self.cached_fixtures(connection, keys_to_fetch = nil) if keys_to_fetch fixtures = cache_for_connection(connection).values_at(*keys_to_fetch) else fixtures = cache_for_connection(connection).values end fixtures.size > 1 ? fixtures : fixtures.first end
# File lib/big_record/fixtures.rb, line 497 def self.create_fixtures(fixtures_directory, table_names, class_names = {}) table_names = [table_names].flatten.map { |n| n.to_s } connection = block_given? ? yield : BigRecord::Base.connection table_names_to_fetch = table_names.reject { |table_name| fixture_is_cached?(connection, table_name) } unless table_names_to_fetch.empty? BigRecord::Base.silence do connection.disable_referential_integrity do fixtures_map = {} fixtures = table_names_to_fetch.map do |table_name| fixtures_map[table_name] = BigRecordFixtures.new(connection, File.split(table_name.to_s).last, class_names[table_name.to_sym], File.join(fixtures_directory, table_name.to_s)) end all_loaded_fixtures.update(fixtures_map) # connection.transaction(Thread.current['open_transactions'].to_i == 0) do fixtures.reverse.each { |fixture| fixture.delete_existing_fixtures } fixtures.each { |fixture| fixture.insert_fixtures } # Cap primary key sequences to max(pk). if connection.respond_to?(:reset_pk_sequence!) table_names.each do |table_name| connection.reset_pk_sequence!(table_name) end end # end cache_fixtures(connection, fixtures) end end end cached_fixtures(connection, table_names) end
# File lib/big_record/fixtures.rb, line 456 def self.fixture_is_cached?(connection, table_name) cache_for_connection(connection)[table_name] end
Returns a consistent identifier for label
. This will always be
a positive integer, and will always be the same for a given label, assuming
the same OS, platform, and version of Ruby.
# File lib/big_record/fixtures.rb, line 536 def self.identify(label) label.to_s.hash.abs end
# File lib/big_record/fixtures.rb, line 488 def self.instantiate_all_loaded_fixtures(object, load_instances = true) all_loaded_fixtures.each do |table_name, fixtures| BigRecordFixtures.instantiate_fixtures(object, table_name, fixtures, load_instances) end end
# File lib/big_record/fixtures.rb, line 473 def self.instantiate_fixtures(object, table_name, fixtures, load_instances = true) object.instance_variable_set "@#{table_name.to_s.gsub('.','_')}", fixtures if load_instances BigRecord::Base.silence do fixtures.each do |name, fixture| begin object.instance_variable_set "@#{name}", fixture.find rescue BigRecordFixtureClassNotFound nil end end end end end
# File lib/big_record/fixtures.rb, line 542 def initialize(connection, table_name, class_name, fixture_path, file_filter = DEFAULT_FILTER_RE) @connection, @table_name, @fixture_path, @file_filter = connection, table_name, fixture_path, file_filter @class_name = class_name || (ActiveRecord::Base.pluralize_table_names ? @table_name.singularize.camelize : @table_name.camelize) @table_name = ActiveRecord::Base.table_name_prefix + @table_name + ActiveRecord::Base.table_name_suffix @table_name = class_name.table_name if class_name.respond_to?(:table_name) @connection = class_name.connection if class_name.respond_to?(:connection) read_fixture_files end
# File lib/big_record/fixtures.rb, line 446 def self.reset_cache(connection = nil) connection ||= BigRecord::Base.connection @@all_cached_big_record_fixtures[connection.object_id] = {} end
Public Instance Methods
# File lib/big_record/fixtures.rb, line 552 def delete_existing_fixtures @connection.get_consecutive_rows(table_name, nil, nil, ["attribute:"]).each do |row| @connection.delete(table_name, row['id']) end end
# File lib/big_record/fixtures.rb, line 558 def insert_fixtures now = ActiveRecord::Base.default_timezone == :utc ? Time.now.utc : Time.now now = now.to_s(:db) # allow a standard key to be used for doing defaults in YAML delete(assoc("DEFAULTS")) # track any join tables we need to insert later habtm_fixtures = Hash.new do |h, habtm| h[habtm] = HabtmFixtures.new(@connection, habtm.options[:join_table], nil, nil) end each do |label, fixture| row = fixture.to_hash if model_class && model_class < ActiveRecord::Base # fill in timestamp columns if they aren't specified and the model is set to record_timestamps if model_class.record_timestamps timestamp_column_names.each do |name| row[name] = now unless row.key?(name) end end # interpolate the fixture label row.each do |key, value| row[key] = label if value == "$LABEL" end # generate a primary key if necessary if has_primary_key_column? && !row.include?(primary_key_name) row[primary_key_name] = BigRecordFixtures.identify(label) end # If STI is used, find the correct subclass for association reflection reflection_class = if row.include?(inheritance_column_name) row[inheritance_column_name].constantize rescue model_class else model_class end reflection_class.reflect_on_all_associations.each do |association| case association.macro when :belongs_to # Do not replace association name with association foreign key if they are named the same fk_name = (association.options[:foreign_key] || "#{association.name}_id").to_s if association.name.to_s != fk_name && value = row.delete(association.name.to_s) if association.options[:polymorphic] if value.sub!(/\s*\(([^\)]*)\)\s*$/, "") target_type = $1 target_type_name = (association.options[:foreign_type] || "#{association.name}_type").to_s # support polymorphic belongs_to as "label (Type)" row[target_type_name] = target_type end end row[fk_name] = BigRecordFixtures.identify(value) end when :has_and_belongs_to_many if (targets = row.delete(association.name.to_s)) targets = targets.is_a?(Array) ? targets : targets.split(/\s*,\s*/) join_fixtures = habtm_fixtures[association] targets.each do |target| join_fixtures["#{label}_#{target}"] = BigRecordFixture.new( { association.primary_key_name => row[primary_key_name], association.association_foreign_key => BigRecordFixtures.identify(target) }, nil) end end end end end @connection.insert_fixture(fixture, @table_name) end # insert any HABTM join tables we discovered habtm_fixtures.values.each do |fixture| fixture.delete_existing_fixtures fixture.insert_fixtures end end
Private Instance Methods
# File lib/big_record/fixtures.rb, line 672 def column_names @column_names ||= @connection.columns(@table_name).collect(&:name) end
# File lib/big_record/fixtures.rb, line 735 def csv_file_path @fixture_path + ".csv" end
FIXME: Turn ERB render back on, conditionnaly…
# File lib/big_record/fixtures.rb, line 750 def erb_render(fixture_content) fixture_content #ERB.new(fixture_content).result end
# File lib/big_record/fixtures.rb, line 657 def has_primary_key_column? @has_primary_key_column ||= model_class && primary_key_name && model_class.columns.find { |c| c.name == primary_key_name } end
# File lib/big_record/fixtures.rb, line 668 def inheritance_column_name @inheritance_column_name ||= model_class && model_class.inheritance_column end
# File lib/big_record/fixtures.rb, line 648 def model_class @model_class ||= @class_name.is_a?(Class) ? @class_name : @class_name.constantize rescue nil end
# File lib/big_record/fixtures.rb, line 743 def parse_yaml_string(fixture_content) YAML::load(erb_render(fixture_content)) rescue => error raise BigRecordFixture::FormatError, "a YAML error occurred parsing #{yaml_file_path}. Please note that YAML must be consistently indented using spaces. Tabs are not allowed. Please have a look at http://www.yaml.org/faq.html\nThe exact error was:\n #{error.class}: #{error}" end
# File lib/big_record/fixtures.rb, line 720 def read_csv_fixture_files reader = CSV::Reader.create(erb_render(IO.read(csv_file_path))) header = reader.shift i = 0 reader.each do |row| data = {} row.each_with_index { |cell, j| data[header[j].to_s.strip] = cell.to_s.strip } self["#{Inflector::underscore(@class_name)}_#{i+=1}"]= BigRecordFixture.new(data, @class_name) end end
# File lib/big_record/fixtures.rb, line 676 def read_fixture_files if File.file?(yaml_file_path) read_yaml_fixture_files elsif File.file?(csv_file_path) read_csv_fixture_files else # Standard fixtures Dir.entries(@fixture_path).each do |file| path = File.join(@fixture_path, file) if File.file?(path) and file !~ @file_filter self[file] = BigRecordFixture.new(path, @class_name) end end end end
# File lib/big_record/fixtures.rb, line 692 def read_yaml_fixture_files yaml_string = "" Dir["#{@fixture_path}/**/*.yml"].select { |f| test(?f, f) }.each do |subfixture_path| yaml_string << IO.read(subfixture_path) end yaml_string << IO.read(yaml_file_path) if yaml = parse_yaml_string(yaml_string) # If the file is an ordered map, extract its children. yaml_value = if yaml.respond_to?(:type_id) && yaml.respond_to?(:value) yaml.value else [yaml] end yaml_value.each do |fixture| fixture.each do |name, data| unless data raise BigRecordFixture::FormatError, "Bad data for #{@class_name} fixture named #{name} (nil)" end self[name] = BigRecordFixture.new(data, @class_name) end end end end
# File lib/big_record/fixtures.rb, line 662 def timestamp_column_names @timestamp_column_names ||= %w(created_at created_on updated_at updated_on).select do |name| column_names.include?(name) end end
# File lib/big_record/fixtures.rb, line 731 def yaml_file_path "#{@fixture_path}.yml" end
# File lib/big_record/fixtures.rb, line 739 def yaml_fixtures_key(path) File.basename(@fixture_path).split(".").first end