1 files changed, 94 insertions, 0 deletions
diff --git a/activerecord/test/cases/associations/extension_test.rb b/activerecord/test/cases/associations/extension_test.rb
new file mode 100644
index 0000000000..5eacb5a3d8
--- /dev/null
+++ b/activerecord/test/cases/associations/extension_test.rb
@@ -0,0 +1,94 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/post"
+require "models/comment"
+require "models/project"
+require "models/developer"
+require "models/computer"
+require "models/company_in_module"
+
+class AssociationsExtensionsTest < ActiveRecord::TestCase
+  fixtures :projects, :developers, :developers_projects, :comments, :posts
+
+  def test_extension_on_has_many
+    assert_equal comments(:more_greetings), posts(:welcome).comments.find_most_recent
+  end
+
+  def test_extension_on_habtm
+    assert_equal projects(:action_controller), developers(:david).projects.find_most_recent
+  end
+
+  def test_named_extension_on_habtm
+    assert_equal projects(:action_controller), developers(:david).projects_extended_by_name.find_most_recent
+  end
+
+  def test_named_two_extensions_on_habtm
+    assert_equal projects(:action_controller), developers(:david).projects_extended_by_name_twice.find_most_recent
+    assert_equal projects(:active_record), developers(:david).projects_extended_by_name_twice.find_least_recent
+  end
+
+  def test_named_extension_and_block_on_habtm
+    assert_equal projects(:action_controller), developers(:david).projects_extended_by_name_and_block.find_most_recent
+    assert_equal projects(:active_record), developers(:david).projects_extended_by_name_and_block.find_least_recent
+  end
+
+  def test_extension_with_scopes
+    assert_equal comments(:greetings), posts(:welcome).comments.offset(1).find_most_recent
+    assert_equal comments(:greetings), posts(:welcome).comments.not_again.find_most_recent
+  end
+
+  def test_extension_with_dirty_target
+    comment = posts(:welcome).comments.build(body: "New comment")
+    assert_equal comment, posts(:welcome).comments.with_content("New comment")
+  end
+
+  def test_marshalling_extensions
+    david = developers(:david)
+    assert_equal projects(:action_controller), david.projects.find_most_recent
+
+    marshalled = Marshal.dump(david)
+
+    # Marshaling an association shouldn't make it unusable by wiping its reflection.
+    assert_not_nil david.association(:projects).reflection
+
+    david_too = Marshal.load(marshalled)
+    assert_equal projects(:action_controller), david_too.projects.find_most_recent
+  end
+
+  def test_marshalling_named_extensions
+    david = developers(:david)
+    assert_equal projects(:action_controller), david.projects_extended_by_name.find_most_recent
+
+    marshalled = Marshal.dump(david)
+    david      = Marshal.load(marshalled)
+
+    assert_equal projects(:action_controller), david.projects_extended_by_name.find_most_recent
+  end
+
+  def test_extension_name
+    extend!(Developer)
+    extend!(MyApplication::Business::Developer)
+
+    assert Object.const_get "DeveloperAssociationNameAssociationExtension"
+    assert MyApplication::Business.const_get "DeveloperAssociationNameAssociationExtension"
+  end
+
+  def test_proxy_association_after_scoped
+    post = posts(:welcome)
+    assert_equal post.association(:comments), post.comments.the_association
+    assert_equal post.association(:comments), post.comments.where("1=1").the_association
+  end
+
+  def test_association_with_default_scope
+    assert_raises OopsError do
+      posts(:welcome).comments.destroy_all
+    end
+  end
+
+  private
+
+    def extend!(model)
+      ActiveRecord::Associations::Builder::HasMany.define_extensions(model, :association_name) {}
+    end
+end