Added cascading eager loading that allows for queries like Author.find(:all, :include=> { :posts=> :comments }), which will fetch all authors, their posts, and the comments belonging to those posts in a single query (using LEFT OUTER JOIN) #3913 [anna@wota.jp]

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@3769 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

1 files changed, 78 insertions, 0 deletions

diff --git a/activerecord/test/associations_cascaded_eager_loading_test.rb b/activerecord/test/associations_cascaded_eager_loading_test.rb
new file mode 100644
index 0000000000..797bc85bc3
--- /dev/null
+++ b/activerecord/test/associations_cascaded_eager_loading_test.rb
@@ -0,0 +1,78 @@
+require 'abstract_unit'
+require 'active_record/acts/list'
+require 'fixtures/post'
+require 'fixtures/comment'
+require 'fixtures/author'
+require 'fixtures/category'
+require 'fixtures/categorization'
+require 'fixtures/mixin'
+require 'fixtures/company'
+require 'fixtures/topic'
+require 'fixtures/reply'
+
+class CascadedEagerLoadingTest < Test::Unit::TestCase
+  fixtures :authors, :mixins, :companies, :posts, :categorizations, :topics
+
+  def test_eager_association_loading_with_cascaded_two_levels
+    authors = Author.find(:all, :include=>{:posts=>:comments}, :order=>"authors.id")
+    assert_equal 2, authors.size
+    assert_equal 5, authors[0].posts.size
+    assert_equal 1, authors[1].posts.size
+    assert_equal 9, authors[0].posts.collect{|post| post.comments.size }.inject(0){|sum,i| sum+i}
+  end
+
+  def test_eager_association_loading_with_cascaded_two_levels_and_one_level
+    authors = Author.find(:all, :include=>[{:posts=>:comments}, :categorizations], :order=>"authors.id")
+    assert_equal 2, authors.size
+    assert_equal 5, authors[0].posts.size
+    assert_equal 1, authors[1].posts.size
+    assert_equal 9, authors[0].posts.collect{|post| post.comments.size }.inject(0){|sum,i| sum+i}
+    assert_equal 1, authors[0].categorizations.size
+    assert_equal 1, authors[1].categorizations.size
+  end
+
+  def test_eager_association_loading_with_cascaded_two_levels_with_two_has_many_associations
+    authors = Author.find(:all, :include=>{:posts=>[:comments, :categorizations]}, :order=>"authors.id")
+    assert_equal 2, authors.size
+    assert_equal 5, authors[0].posts.size
+    assert_equal 1, authors[1].posts.size
+    assert_equal 9, authors[0].posts.collect{|post| post.comments.size }.inject(0){|sum,i| sum+i}
+  end
+
+  def test_eager_association_loading_with_cascaded_two_levels_and_self_table_reference
+    authors = Author.find(:all, :include=>{:posts=>[:comments, :author]}, :order=>"authors.id")
+    assert_equal 2, authors.size
+    assert_equal 5, authors[0].posts.size
+    assert_equal authors(:david).name, authors[0].name
+    assert_equal [authors(:david).name], authors[0].posts.collect{|post| post.author.name}.uniq
+  end
+
+  def test_eager_association_loading_with_cascaded_two_levels_with_condition
+    authors = Author.find(:all, :include=>{:posts=>:comments}, :conditions=>"authors.id=1", :order=>"authors.id")
+    assert_equal 1, authors.size
+    assert_equal 5, authors[0].posts.size
+  end
+
+  def test_eager_association_loading_with_acts_as_tree
+    roots = TreeMixin.find(:all, :include=>"children", :conditions=>"mixins.parent_id IS NULL", :order=>"mixins.id")
+    assert_equal [mixins(:tree_1), mixins(:tree2_1), mixins(:tree3_1)], roots
+    assert_equal 2, roots[0].children.size
+    assert_equal 0, roots[1].children.size
+    assert_equal 0, roots[2].children.size
+  end
+
+  def test_eager_association_loading_with_cascaded_three_levels_by_ping_pong
+    firms = Firm.find(:all, :include=>{:account=>{:firm=>:account}}, :order=>"companies.id")
+    assert_equal 2, firms.size
+    assert_equal firms.first.account, firms.first.account.firm.account
+    assert_equal companies(:first_firm).account, firms.first.account.firm.account
+    assert_equal companies(:first_firm).account.firm.account, firms.first.account.firm.account
+  end
+
+  def test_eager_association_loading_with_sti
+    topics = Topic.find(:all, :include => :replies, :order => 'topics.id')
+    assert_equal [topics(:first), topics(:second)], topics
+    assert_equal 1, topics[0].replies.size
+    assert_equal 0, topics[1].replies.size
+  end
+end