[rails] has_many association; collection count, size and length

has_many_association_collection.rb

# in user model:
# has_many :pins_relationship, class_name: 'Action', conditions: {kind: 'pin'}
# has_many :pins, through: :pins_relationship, source: :stuff, uniq: true

it "pin place (duplicate check)" do
	@alice.pins << Stuff.find_or_create_by_kind_and_name!(kind: 'landmark', name: "お気に入り喫茶店")
	@alice.pins << Stuff.find_or_create_by_kind_and_name!(kind: 'landmark', name: "お気に入り喫茶店")
	@alice.pins.where(kind: 'landmark', name: "お気に入り喫茶店").count.should == 2		
	@alice.pins.where(kind: 'landmark', name: "お気に入り喫茶店").size.should == 2
	@alice.pins.where(kind: 'landmark', name: "お気に入り喫茶店").length.should == 1
end