Support ordered YAML fixtures. #1896

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@2600 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

activerecord/CHANGELOG

@@ -1,5 +1,5 @@
 *SVN*                                                                                                                   
-=======
+* YAML fixtures support ordered hashes for fixtures with foreign key dependencies in the same table.  #1896 [purestorm@ggnore.net]
 
 * :dependent now accepts :nullify option. Sets the foreign key of the related objects to NULL instead of deleting them. #2015 [Robby Russell <robby@planetargon.com>] 
 

activerecord/lib/active_record/fixtures.rb

@@ -38,6 +38,20 @@ end
 # 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
+#
 # = CSV fixtures
 #
 # Fixtures can also be kept in the Comma Separated Value format. Akin to YAML fixtures, CSV fixtures are stored
@@ -293,8 +307,12 @@ class Fixtures < YAML::Omap
       if File.file?(yaml_file_path)
         # YAML fixtures
         begin
-          yaml = YAML::load(erb_render(IO.read(yaml_file_path)))
+          if yaml = YAML::load(erb_render(IO.read(yaml_file_path)))
-          yaml.each { |name, data| self[name] = Fixture.new(data, @class_name) } if yaml
+            yaml = yaml.value if yaml.kind_of?(YAML::Syck::PrivateType)
+            yaml.each do |name, data|
+              self[name] = Fixture.new(data, @class_name)
+            end
+          end
         rescue Exception=>boom
           raise Fixture::FormatError, "a YAML error occured 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  #{boom.class}: #{boom}"
         end
@@ -350,7 +368,15 @@ class Fixture #:nodoc:
   end
 
   def initialize(fixture, class_name)
-    @fixture = fixture.is_a?(Hash) ? fixture : read_fixture_file(fixture)
+    case fixture
+      when Hash, YAML::Omap
+        @fixture = fixture
+      when String
+        @fixture = read_fixture_file(fixture)
+      else
+        raise ArgumentError, "Bad fixture argument #{fixture.inspect}"
+    end
+
     @class_name = class_name
   end
 

activerecord/test/fixtures/categories_ordered.yml

@@ -0,0 +1,7 @@
+--- !omap
+<% 100.times do |i| %>
+- fixture_no_<%= i %>:
+    id: <%= i %>
+    name: <%= "Category #{i}" %>
+    type: Category
+<% end %>

activerecord/test/fixtures_test.rb

@@ -155,6 +155,19 @@ class FixturesTest < Test::Unit::TestCase
   def test_empty_csv_fixtures
     assert_not_nil Fixtures.new( Account.connection, "accounts", File.dirname(__FILE__) + "/fixtures/naked/csv/accounts")
   end
+
+  def test_omap_fixtures
+    assert_nothing_raised do
+      fixtures = Fixtures.new(Account.connection, 'categories', File.dirname(__FILE__) + '/fixtures/categories_ordered')
+
+      i = 0
+      fixtures.each do |name, fixture|
+        assert_equal "fixture_no_#{i}", name
+        assert_equal "Category #{i}", fixture['name']
+        i += 1
+      end
+    end
+  end
 end