因此，我正在为一种方法编写测试，该方法出于性能原因应该在不使用 SQL 查询的情况下实现它需要实现的目标。我在想我需要知道的就是存根：
describe SomeModel do
describe 'a_getter_method' do
it 'should not touch the database' do
thing = SomeModel.create
something_inside_rails.should_not_receive(:a_method_querying_the_database)
thing.a_getter_method
end
end
end
编辑：提供一个更具体的例子：
class Publication << ActiveRecord::Base
end
class Book << Publication
end
class Magazine << Publication
end
class Student << ActiveRecord::Base
has_many :publications
def publications_of_type(type)
#this is the method I am trying to test.
#The test should show that when I do the following, the database is queried.
self.publications.find_all_by_type(type)
end
end
describe Student do
describe "publications_of_type" do
it 'should not touch the database' do
Student.create()
student = Student.first(:include => :publications)
#the publications relationship is already loaded, so no need to touch the DB
lambda {
student.publications_of_type(:magazine)
}.should_not touch_the_database
end
end
end
所以在这个例子中测试应该失败，因为 rails 'find_all_by' 方法依赖于 SQL。