# File lib/dm-fixtures/fixtures.rb, line 650 def primary_key_name #TODO don't know that the multiple column thing actually reflects datamapper realities @primary_key_name ||= model_class && model_class.key.collect{|c| c.name }.join('-') end
class DataMapper::Fixtures
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 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 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 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, test_helper.rb
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.
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 <%= 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
¶ ↑
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:
-
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.
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 (monkey_id: 1
).
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 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 a hold of the identifier for a given label. ERB to the rescue:
george_reginald: monkey_id: <%= DataMapper::Fixtures.identify(:reginald) %> pirate_id: <%= DataMapper::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
- MAX_ID
Attributes
Public Class Methods
# File lib/dm-fixtures/fixtures.rb, line 422 def self.cache_fixtures(connection, fixtures_map) cache_for_connection(connection).update(fixtures_map) end
# File lib/dm-fixtures/fixtures.rb, line 406 def self.cache_for_connection(connection) @@all_cached_fixtures[connection] end
# File lib/dm-fixtures/fixtures.rb, line 414 def self.cached_fixtures(connection, keys_to_fetch = nil) if keys_to_fetch cache_for_connection(connection).values_at(*keys_to_fetch) else cache_for_connection(connection).values end end
# File lib/dm-fixtures/fixtures.rb, line 466 def self.create_fixtures(fixtures_directory, table_names, class_names = {}) table_names = [table_names].flatten.map { |n| n.to_s } table_names.each { |n| class_names[n.tr('/', '_').to_sym] = n.classify if n.include?('/') } connection = block_given? ? yield : DataMapper.repository #ActiveRecord::Base.connection files_to_read = table_names.reject { |table_name| fixture_is_cached?(connection, table_name) } unless files_to_read.empty? connection.adapter.disable_referential_integrity do fixtures_map = {} fixture_files = files_to_read.map do |path| table_name = path.tr '/', '_' fixtures_map[path] = DataMapper::Fixtures.new( connection, table_name, !class_names.empty? ? class_names[table_name.to_sym] : table_name.classify, ::File.join(fixtures_directory, path) ) end all_loaded_fixtures.update(fixtures_map) # Implicitly already in transaction if necessary #connection.transaction do #(:requires_new => true) fixture_files.each do |ff| conn = ff.model_class.respond_to?(:current_connection) ? ff.model_class.current_connection : connection table_rows = ff.table_rows table_rows.keys.each do |table| # Delete all fixtures from table using their id #conn.delete "DELETE FROM #{conn.quote_table_name(table)}", 'Fixture Delete' success = ff.model_class.destroy! end table_rows.each do |table_name,rows| rows.each do |row| #conn.insert_fixture(row, table_name) #TODO ff.model_class.create!(row.symbolize_keys) end end end # 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.tr('/', '_')) end end #end cache_fixtures(connection, fixtures_map) end end cached_fixtures(connection, table_names) end
# File lib/dm-fixtures/fixtures.rb, line 410 def self.fixture_is_cached?(connection, table_name) cache_for_connection(connection)[table_name] end
Returns a consistent, platform-independent identifier for label
. Identifiers are positive integers less than 2^32.
# File lib/dm-fixtures/fixtures.rb, line 531 def self.identify(label) Zlib.crc32(label.to_s) % MAX_ID end
# File lib/dm-fixtures/fixtures.rb, line 457 def self.instantiate_all_loaded_fixtures(object, load_instances = true) all_loaded_fixtures.each_value do |fixture_set| DataMapper::Fixtures.instantiate_fixtures(object, fixture_set, load_instances) end end
The use with parameters (object, fixture_set_name, fixture_set, load_instances = true)
is deprecated, fixture_set_name
parameter is not used. Use as:
instantiate_fixtures(object, fixture_set, load_instances = true)
# File lib/dm-fixtures/fixtures.rb, line 446 def self.instantiate_fixtures(object, fixture_set, load_instances = true, rails_3_2_compatibility_argument = true) unless load_instances == true || load_instances == false ActiveSupport::Deprecation.warn( "ActiveRecord::Fixtures.instantiate_fixtures with parameters (object, fixture_set_name, fixture_set, load_instances = true) is deprecated and shall be removed from future releases. Use it with parameters (object, fixture_set, load_instances = true) instead (skip fixture_set_name).", caller) fixture_set = load_instances load_instances = rails_3_2_compatibility_argument end instantiate_fixtures__with_new_arity(object, fixture_set, load_instances) end
# File lib/dm-fixtures/fixtures.rb, line 537 def initialize(connection, table_name, class_name, fixture_path) @connection = connection # instance of DataMapper::Repository (usually DataMapper.repository) @table_name = table_name @fixture_path = fixture_path @name = table_name # preserve fixture base name @class_name = class_name @fixtures = ActiveSupport::OrderedHash.new @table_name = DataMapper.repository.adapter.resource_naming_convention.call(@table_name) # Should be a class that: `include DataMapper::Resource` if class_name.is_a?(Class) @table_name = class_name.table_name @connection = class_name.connection @model_class = class_name else @model_class = class_name.constantize rescue nil end read_fixture_files end
# File lib/dm-fixtures/fixtures.rb, line 402 def self.reset_cache @@all_cached_fixtures.clear end
Public Instance Methods
# File lib/dm-fixtures/fixtures.rb, line 559 def [](x) fixtures[x] end
# File lib/dm-fixtures/fixtures.rb, line 563 def []=(k,v) fixtures[k] = v end
# File lib/dm-fixtures/fixtures.rb, line 567 def each(&block) fixtures.each(&block) end
# File lib/dm-fixtures/fixtures.rb, line 571 def size fixtures.size end
Return a hash of rows to be inserted. The key is the table, the value is a list of rows to insert to that table.
# File lib/dm-fixtures/fixtures.rb, line 577 def table_rows now = Time.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 fixtures.delete('DEFAULTS') # track any join tables we need to insert later rows = Hash.new { |h,table| h[table] = [] } rows[table_name] = fixtures.map do |label, fixture| row = fixture.to_hash if model_class && DataMapper::Model.descendants.entries.include?(model_class) #model_class < ActiveRecord::Base # fill in timestamp columns if they aren't specified and the model has appropriately named columns if has_timestamp_columns? 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] = DataMapper::Fixtures.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 reflect_on_all_associations(reflection_class).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] && value.sub!(/\s*\(([^\)]*)\)\s*$/, "") # support polymorphic belongs_to as "label (Type)" row[association.foreign_type] = $1 end row[fk_name] = DataMapper::Fixtures.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*/) table_name = association.options[:join_table] rows[table_name].concat targets.map { |target| { association.foreign_key => row[primary_key_name], association.association_foreign_key => DataMapper::Fixtures.identify(target) } } end end end end row end rows end
Private Instance Methods
# File lib/dm-fixtures/fixtures.rb, line 674 def column_names @column_names ||= model_class.properties.collect{|prop| prop.name.to_s } #@connection.columns(@table_name).collect { |c| c.name } end
# File lib/dm-fixtures/fixtures.rb, line 655 def has_primary_key_column? @has_primary_key_column ||= primary_key_name() && model_class.properties.any? { |c| c.name.to_s == primary_key_name } end
# File lib/dm-fixtures/fixtures.rb, line 660 def has_timestamp_columns? !timestamp_column_names.empty? end
# File lib/dm-fixtures/fixtures.rb, line 670 def inheritance_column_name @inheritance_column_name ||= model_class && model_class.properties.select{|prop| prop.kind_of? DataMapper::Property::Discriminator }.collect{|c| c.name.to_s }.first end
Returns primary key name as string, can be composite key with multiple columns
# File lib/dm-fixtures/fixtures.rb, line 724 def read_fixture_files yaml_files = Dir["#{@fixture_path}/**/*.yml"].select { |f| ::File.file?(f) } + [yaml_file_path] yaml_files.each do |file| Fixtures::File.open(file) do |fh| fh.each do |name, row| fixtures[name] = DataMapper::Fixture.new(row, model_class) end end end end
pastie.org/pastes/233178 Semi-equivalent of ActiveRecord’s reflect_on_all_associations
method
# File lib/dm-fixtures/fixtures.rb, line 680 def reflect_on_all_associations klass klass.relationships.collect do |relationship| # All can be child/parent # ManyToMany # ManyToOne # OneToMany # OneToOne #TODO :has_and_belongs_to_many if relationship.kind_of?(::DataMapper::Associations::ManyToOne::Relationship) && relationship.child_model? #relationship.options[:min] == 1 && relationship.options[:max] == 1 macro = :belongs_to if relationship.options[:class_name] # In a belongs_to, the side with the class name uses # the parent model, but child key for the foreign key... class_name = relationship.parent_model.to_s primary_key_name = relationship.child_key.entries.first.name else class_name = relationship.child_model.to_s primary_key_name = relationship.parent_key.entries.first.name end else macro = :has_one if relationship.options[:class_name] # but on the has_one side, it's the *child* model that # uses the child key for the foreign key. Weirdness. class_name = relationship.child_model.to_s primary_key_name = relationship.child_key.entries.first.name else class_name = relationship.parent_model.to_s primary_key_name = relationship.parent_key.entries.first.name end end OpenStruct.new( :name => relationship.name, :options => { #:foreign_key => , # Ignore, let the calling code infer: {name}_id :polymorphic => false # Hard code for now }, :class_name => class_name, :primary_key_name => primary_key_name, :macro => macro ) end end
# File lib/dm-fixtures/fixtures.rb, line 664 def timestamp_column_names # comparison to strings here means all names are in strings @timestamp_column_names ||= %w(created_at created_on updated_at updated_on) & column_names end
# File lib/dm-fixtures/fixtures.rb, line 738 def yaml_file_path "#{@fixture_path}.yml" end