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author | Xavier Noria <fxn@hashref.com> | 2011-09-03 15:20:18 -0700 |
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committer | Xavier Noria <fxn@hashref.com> | 2011-09-03 15:20:30 -0700 |
commit | 0a38e2a5ce2eaf7393958721edbfcf2a7fe87334 (patch) | |
tree | c71de2f3141300202d4bc11b2119fa49bea408ec /activerecord/lib | |
parent | 510a9707d8a3af5a81006cdb25e8089025acada1 (diff) | |
download | rails-0a38e2a5ce2eaf7393958721edbfcf2a7fe87334.tar.gz rails-0a38e2a5ce2eaf7393958721edbfcf2a7fe87334.tar.bz2 rails-0a38e2a5ce2eaf7393958721edbfcf2a7fe87334.zip |
restores the API docs of AR::Fixtures, made a quick pass over them, revises link in fixture template [closes #2840]
Diffstat (limited to 'activerecord/lib')
-rw-r--r-- | activerecord/lib/active_record/fixtures.rb | 729 |
1 files changed, 361 insertions, 368 deletions
diff --git a/activerecord/lib/active_record/fixtures.rb b/activerecord/lib/active_record/fixtures.rb index 2674430116..6f1ec7f9b3 100644 --- a/activerecord/lib/active_record/fixtures.rb +++ b/activerecord/lib/active_record/fixtures.rb @@ -24,375 +24,368 @@ end class FixturesFileNotFound < StandardError; end -# Fixtures are a way of organizing data that you want to test against; in short, sample data. -# -# = Fixture formats -# -# Fixtures come in 1 flavor: -# -# 1. YAML 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 <tt>ActiveSupport::TestCase.fixture_path=(path)</tt> (this is -# automatically configured for Rails, so you can just put your files in <tt><your-rails-app>/test/fixtures/</tt>). -# The fixture file ends with the <tt>.yml</tt> file extension (Rails example: -# <tt><your-rails-app>/test/fixtures/web_sites.yml</tt>). 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 http://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 -# -# = Using fixtures in testcases -# -# 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 <tt>test_helper module</tt> 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 <tt>ActiveSupport::TestCase</tt>-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. -# -# = 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 fixtures to create a bunch of fixtures for load testing, like: -# -# <% (1..1000).each do |i| %> -# 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 <tt><%= Date.today.strftime("%Y-%m-%d") %></tt>. -# 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. -# -# class FooTest < ActiveSupport::TestCase -# self.use_transactional_fixtures = true -# -# test "godzilla" do -# assert !Foo.all.empty? -# Foo.destroy_all -# assert Foo.all.empty? -# end -# -# test "godzilla aftermath" do -# assert !Foo.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 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 -# -# == Stable, autogenerated IDs -# -# 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. -# -# == 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 Active Record 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 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* (<tt>monkey_id: 1</tt>). -# -# ==== Polymorphic belongs_to -# -# 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. -# -# === has_and_belongs_to_many -# -# 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. -# -# == Autofilled timestamp columns -# -# 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 <tt>Time.now</tt>. -# -# 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 a hold of the identifier for a given label. ERB -# to the rescue: -# -# george_reginald: -# monkey_id: <%= ActiveRecord::Fixtures.identify(:reginald) %> -# pirate_id: <%= ActiveRecord::Fixtures.identify(:george) %> -# -# == Support for YAML defaults -# -# You probably already know how to use YAML to set and reuse defaults in -# your <tt>database.yml</tt> 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. - module ActiveRecord + # \Fixtures are a way of organizing data that you want to test against; in short, sample data. + # + # They are stored in YAML files, one file per model, which are placed in the directory + # appointed by <tt>ActiveSupport::TestCase.fixture_path=(path)</tt> (this is automatically + # configured for Rails, so you can just put your files in <tt><your-rails-app>/test/fixtures/</tt>). + # The fixture file ends with the <tt>.yml</tt> file extension (Rails example: + # <tt><your-rails-app>/test/fixtures/web_sites.yml</tt>). The format of a 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 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 fixtures are unordered. If you want ordered fixtures, use the omap YAML type. + # See http://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 + # + # = Using Fixtures in Test Cases + # + # 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, <tt>test_helper.rb</tt> 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 <tt>ActiveSupport::TestCase</tt>-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. + # + # = 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 fixtures to create a bunch of fixtures for load + # testing, like: + # + # <% 1.upto(1000) do |i| %> + # fix_<%= i %>: + # id: <%= i %> + # name: guy_<%= 1 %> + # <% end %> + # + # This will create 1000 very simple fixtures. + # + # Using ERB, you can also inject dynamic values into your fixtures with inserts like + # <tt><%= Date.today.strftime("%Y-%m-%d") %></tt>. + # 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 + # + # Test cases 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.all.empty? + # Foo.destroy_all + # assert Foo.all.empty? + # end + # + # test "godzilla aftermath" do + # assert !Foo.all.empty? + # end + # end + # + # If you preload your test database with all fixture data (probably in the rake 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 Fixtures + # + # 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 + # + # == Stable, Autogenerated IDs + # + # 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. + # + # == 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 Active Record 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 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* (<tt>monkey_id: 1</tt>). + # + # ==== Polymorphic belongs_to + # + # 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. + # + # === has_and_belongs_to_many + # + # 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. + # + # == Autofilled Timestamp Columns + # + # 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 <tt>Time.now</tt>. + # + # 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 a hold of the identifier for a given label. ERB + # to the rescue: + # + # george_reginald: + # monkey_id: <%= ActiveRecord::Fixtures.identify(:reginald) %> + # pirate_id: <%= ActiveRecord::Fixtures.identify(:george) %> + # + # == Support for YAML defaults + # + # You probably already know how to use YAML to set and reuse defaults in + # your <tt>database.yml</tt> 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. class Fixtures MAX_ID = 2 ** 30 - 1 |