# File lib/active_record/fixtures.rb, line 674 674: def primary_key_name 675: @primary_key_name ||= model_class && model_class.primary_key 676: end
(RUBY_VERSION < '1.9' ? YAML::Omap : Hash)
Fixtures are a way of organizing data that you want to test against; in short, sample data.
Fixtures come in 3 flavors:
1. YAML fixtures 2. CSV fixtures 3. Single-file 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 ActiveSupport::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
Fixtures can also be kept in the Comma Separated Value (CSV) 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.
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 ActiveSupport::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
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 'test_helper' class WebSiteTest < ActiveSupport::TestCase test "web_site_count" do assert_equal 2, WebSite.count end end
By default, the test_helper module will load all of your fixtures into your test database, so this test will succeed. The testing environment will automatically load the all 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 fixture’s data may also be accessed by using a special dynamic method, which has the same name as the model, and accepts the name of the fixture to instantiate:
test "find" do assert_equal "Ruby on Rails", web_sites(:rubyonrails).name end
Alternatively, you may enable auto-instantiation of the fixture data. For instance, take the following tests:
test "find_alt_method_1" do assert_equal "Ruby on Rails", @web_sites['rubyonrails']['name'] end test "find_alt_method_2" do assert_equal "Ruby on Rails", @rubyonrails.news end
In order to use these methods to access fixtured data within your testcases, you must specify one of the following in your ActiveSupport::TestCase-derived class:
to fully enable instantiated fixtures (enable alternate methods #1 and #2 above)
self.use_instantiated_fixtures = true
create only the hash for the fixtures, do not ‘find’ each instance (enable alternate method #1 only)
self.use_instantiated_fixtures = :no_instances
Using either of these alternate methods incurs a performance hit, as the fixtured data must be fully traversed in the database to create the fixture hash and/or instance variables. This is expensive for large sets of fixtured data.
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.
TestCases can use begin+rollback to isolate their changes to the database instead of having to delete+insert for every test case.
class FooTest < ActiveSupport::TestCase self.use_transactional_fixtures = true test "godzilla" do assert !Foo.find(:all).empty? Foo.destroy_all assert Foo.find(:all).empty? end test "godzilla aftermath" do 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:
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).
Your database does not support transactions. Every Active Record database supports transactions except MySQL MyISAM. Use InnoDB, MaxDB, or NDB instead.
YAML fixtures that don’t specify an ID get some extra features:
Stable, autogenerated IDs
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
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
Active Record 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.
Specifying foreign keys in fixtures can be very fragile, not to mention difficult to read. Since Active Record can figure out the ID of any fixture from its label, you can specify FK’s by label instead of ID.
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 IDs:
### 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. Active Record 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).
Supporting polymorphic relationships is a little bit more complicated, since Active Record 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 Active Record will take care of the rest.
Time to give our monkey some fruit.
### in monkeys.yml george: id: 1 name: George the Monkey ### 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: id: 1 name: George the Monkey 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, Active Record reflects on the fixture’s model class and discovers the has_and_belongs_to_many associations.
If your table/model specifies any of Active Record’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.
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 a hold of the identifier for a given label. ERB to the rescue:
george_reginald: monkey_id: <%= Fixtures.identify(:reginald) %> pirate_id: <%= Fixtures.identify(:george) %>
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.
# File lib/active_record/fixtures.rb, line 478 478: def self.cache_fixtures(connection, fixtures_map) 479: cache_for_connection(connection).update(fixtures_map) 480: end
# File lib/active_record/fixtures.rb, line 460 460: def self.cache_for_connection(connection) 461: @@all_cached_fixtures[connection.object_id] ||= {} 462: @@all_cached_fixtures[connection.object_id] 463: end
# File lib/active_record/fixtures.rb, line 469 469: def self.cached_fixtures(connection, keys_to_fetch = nil) 470: if keys_to_fetch 471: fixtures = cache_for_connection(connection).values_at(*keys_to_fetch) 472: else 473: fixtures = cache_for_connection(connection).values 474: end 475: fixtures.size > 1 ? fixtures : fixtures.first 476: end
# File lib/active_record/fixtures.rb, line 506 506: def self.create_fixtures(fixtures_directory, table_names, class_names = {}) 507: table_names = [table_names].flatten.map { |n| n.to_s } 508: table_names.each { |n| class_names[n.tr('/', '_').to_sym] = n.classify if n.include?('/') } 509: connection = block_given? ? yield : ActiveRecord::Base.connection 510: 511: table_names_to_fetch = table_names.reject { |table_name| fixture_is_cached?(connection, table_name) } 512: 513: unless table_names_to_fetch.empty? 514: ActiveRecord::Base.silence do 515: connection.disable_referential_integrity do 516: fixtures_map = {} 517: 518: fixtures = table_names_to_fetch.map do |table_name| 519: fixtures_map[table_name] = Fixtures.new(connection, table_name.tr('/', '_'), class_names[table_name.tr('/', '_').to_sym], File.join(fixtures_directory, table_name)) 520: end 521: 522: all_loaded_fixtures.update(fixtures_map) 523: 524: connection.transaction(:requires_new => true) do 525: fixtures.reverse.each { |fixture| fixture.delete_existing_fixtures } 526: fixtures.each { |fixture| fixture.insert_fixtures } 527: 528: # Cap primary key sequences to max(pk). 529: if connection.respond_to?(:reset_pk_sequence!) 530: table_names.each do |table_name| 531: connection.reset_pk_sequence!(table_name.tr('/', '_')) 532: end 533: end 534: end 535: 536: cache_fixtures(connection, fixtures_map) 537: end 538: end 539: end 540: cached_fixtures(connection, table_names) 541: end
# File lib/active_record/fixtures.rb, line 465 465: def self.fixture_is_cached?(connection, table_name) 466: cache_for_connection(connection)[table_name] 467: end
Returns a consistent, platform-independent identifier for label. Identifiers are positive integers less than 2^32.
# File lib/active_record/fixtures.rb, line 545 545: def self.identify(label) 546: Zlib.crc32(label.to_s) % MAX_ID 547: end
# File lib/active_record/fixtures.rb, line 497 497: def self.instantiate_all_loaded_fixtures(object, load_instances = true) 498: all_loaded_fixtures.each do |table_name, fixtures| 499: Fixtures.instantiate_fixtures(object, table_name, fixtures, load_instances) 500: end 501: end
# File lib/active_record/fixtures.rb, line 482 482: def self.instantiate_fixtures(object, table_name, fixtures, load_instances = true) 483: object.instance_variable_set "@#{table_name.to_s.gsub('.','_')}", fixtures 484: if load_instances 485: ActiveRecord::Base.silence do 486: fixtures.each do |name, fixture| 487: begin 488: object.instance_variable_set "@#{name}", fixture.find 489: rescue FixtureClassNotFound 490: nil 491: end 492: end 493: end 494: end 495: end
# File lib/active_record/fixtures.rb, line 551 551: def initialize(connection, table_name, class_name, fixture_path, file_filter = DEFAULT_FILTER_RE) 552: @connection, @table_name, @fixture_path, @file_filter = connection, table_name, fixture_path, file_filter 553: @name = table_name # preserve fixture base name 554: @class_name = class_name || 555: (ActiveRecord::Base.pluralize_table_names ? @table_name.singularize.camelize : @table_name.camelize) 556: @table_name = "#{ActiveRecord::Base.table_name_prefix}#{@table_name}#{ActiveRecord::Base.table_name_suffix}" 557: @table_name = class_name.table_name if class_name.respond_to?(:table_name) 558: @connection = class_name.connection if class_name.respond_to?(:connection) 559: read_fixture_files 560: end
# File lib/active_record/fixtures.rb, line 562 562: def delete_existing_fixtures 563: @connection.delete "DELETE FROM #{@connection.quote_table_name(table_name)}", 'Fixture Delete' 564: end
# File lib/active_record/fixtures.rb, line 566 566: def insert_fixtures 567: now = ActiveRecord::Base.default_timezone == :utc ? Time.now.utc : Time.now 568: now = now.to_s(:db) 569: 570: # allow a standard key to be used for doing defaults in YAML 571: if is_a?(Hash) 572: delete('DEFAULTS') 573: else 574: delete(assoc('DEFAULTS')) 575: end 576: 577: # track any join tables we need to insert later 578: habtm_fixtures = Hash.new do |h, habtm| 579: h[habtm] = HabtmFixtures.new(@connection, habtm.options[:join_table], nil, nil) 580: end 581: 582: each do |label, fixture| 583: row = fixture.to_hash 584: 585: if model_class && model_class < ActiveRecord::Base 586: # fill in timestamp columns if they aren't specified and the model is set to record_timestamps 587: if model_class.record_timestamps 588: timestamp_column_names.each do |name| 589: row[name] = now unless row.key?(name) 590: end 591: end 592: 593: # interpolate the fixture label 594: row.each do |key, value| 595: row[key] = label if value == "$LABEL" 596: end 597: 598: # generate a primary key if necessary 599: if has_primary_key_column? && !row.include?(primary_key_name) 600: row[primary_key_name] = Fixtures.identify(label) 601: end 602: 603: # If STI is used, find the correct subclass for association reflection 604: reflection_class = 605: if row.include?(inheritance_column_name) 606: row[inheritance_column_name].constantize rescue model_class 607: else 608: model_class 609: end 610: 611: reflection_class.reflect_on_all_associations.each do |association| 612: case association.macro 613: when :belongs_to 614: # Do not replace association name with association foreign key if they are named the same 615: fk_name = (association.options[:foreign_key] || "#{association.name}_id").to_s 616: 617: if association.name.to_s != fk_name && value = row.delete(association.name.to_s) 618: if association.options[:polymorphic] 619: if value.sub!(/\s*\(([^\)]*)\)\s*$/, "") 620: target_type = $1 621: target_type_name = (association.options[:foreign_type] || "#{association.name}_type").to_s 622: 623: # support polymorphic belongs_to as "label (Type)" 624: row[target_type_name] = target_type 625: end 626: end 627: 628: row[fk_name] = Fixtures.identify(value) 629: end 630: when :has_and_belongs_to_many 631: if (targets = row.delete(association.name.to_s)) 632: targets = targets.is_a?(Array) ? targets : targets.split(/\s*,\s*/) 633: join_fixtures = habtm_fixtures[association] 634: 635: targets.each do |target| 636: join_fixtures["#{label}_#{target}"] = Fixture.new( 637: { association.primary_key_name => row[primary_key_name], 638: association.association_foreign_key => Fixtures.identify(target) }, 639: nil, @connection) 640: end 641: end 642: end 643: end 644: end 645: 646: @connection.insert_fixture(fixture, @table_name) 647: end 648: 649: # insert any HABTM join tables we discovered 650: habtm_fixtures.values.each do |fixture| 651: fixture.delete_existing_fixtures 652: fixture.insert_fixtures 653: end 654: end
# File lib/active_record/fixtures.rb, line 692 692: def column_names 693: @column_names ||= @connection.columns(@table_name).collect { |c| c.name } 694: end
# File lib/active_record/fixtures.rb, line 750 750: def csv_file_path 751: @fixture_path + ".csv" 752: end
# File lib/active_record/fixtures.rb, line 764 764: def erb_render(fixture_content) 765: ERB.new(fixture_content).result 766: end
# File lib/active_record/fixtures.rb, line 678 678: def has_primary_key_column? 679: @has_primary_key_column ||= primary_key_name && 680: model_class.columns.any? { |c| c.name == primary_key_name } 681: end
# File lib/active_record/fixtures.rb, line 688 688: def inheritance_column_name 689: @inheritance_column_name ||= model_class && model_class.inheritance_column 690: end
# File lib/active_record/fixtures.rb, line 661 661: def model_class 662: unless defined?(@model_class) 663: @model_class = 664: if @class_name.nil? || @class_name.is_a?(Class) 665: @class_name 666: else 667: @class_name.constantize rescue nil 668: end 669: end 670: 671: @model_class 672: end
# File lib/active_record/fixtures.rb, line 758 758: def parse_yaml_string(fixture_content) 759: YAML::load(erb_render(fixture_content)) 760: rescue => error 761: raise Fixture::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}" 762: end
# File lib/active_record/fixtures.rb, line 674 674: def primary_key_name 675: @primary_key_name ||= model_class && model_class.primary_key 676: end
# File lib/active_record/fixtures.rb, line 735 735: def read_csv_fixture_files 736: reader = CSV.parse(erb_render(IO.read(csv_file_path))) 737: header = reader.shift 738: i = 0 739: reader.each do |row| 740: data = {} 741: row.each_with_index { |cell, j| data[header[j].to_s.strip] = cell.to_s.strip } 742: self["#{@class_name.to_s.underscore}_#{i+=1}"] = Fixture.new(data, model_class, @connection) 743: end 744: end
# File lib/active_record/fixtures.rb, line 696 696: def read_fixture_files 697: if File.file?(yaml_file_path) 698: read_yaml_fixture_files 699: elsif File.file?(csv_file_path) 700: read_csv_fixture_files 701: else 702: raise FixturesFileNotFound, "Could not find #{yaml_file_path} or #{csv_file_path}" 703: end 704: end
# File lib/active_record/fixtures.rb, line 706 706: def read_yaml_fixture_files 707: yaml_string = "" 708: Dir["#{@fixture_path}/**/*.yml"].select { |f| test(ff, f) }.each do |subfixture_path| 709: yaml_string << IO.read(subfixture_path) 710: end 711: yaml_string << IO.read(yaml_file_path) 712: 713: if yaml = parse_yaml_string(yaml_string) 714: # If the file is an ordered map, extract its children. 715: yaml_value = 716: if yaml.respond_to?(:type_id) && yaml.respond_to?(:value) 717: yaml.value 718: else 719: [yaml] 720: end 721: 722: yaml_value.each do |fixture| 723: raise Fixture::FormatError, "Bad data for #{@class_name} fixture named #{fixture}" unless fixture.respond_to?(:each) 724: fixture.each do |name, data| 725: unless data 726: raise Fixture::FormatError, "Bad data for #{@class_name} fixture named #{name} (nil)" 727: end 728: 729: self[name] = Fixture.new(data, model_class, @connection) 730: end 731: end 732: end 733: end
# File lib/active_record/fixtures.rb, line 683 683: def timestamp_column_names 684: @timestamp_column_names ||= 685: %(created_at created_on updated_at updated_on) & column_names 686: end
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