ruby on rails - Testing if an instance of a class receives a message when a class method that sends the message to all instances is called -

though correct, title needs explanation :)

i have class:

class character   include datamapper::resource    def self.tick_all     all.collect &:tick   end    def tick     # stuff   end  end 

as can see when character.tick_all called instances should receive tick invocation. works exptected: when fire console stuff in tick gets done. can't tests pass:

describe ".tick_all"   let(:instance) { factorygirl.create(:character) }   "invokes #tick every instance"     character.tick_all     instance.should_receive(:tick)   end end 

failed example:

failure/error: instance.should_receive(:tick)   (#<character:0x00000002fa4e28>).tick(any args)       expected: 1 time       received: 0 times 

the expectation should set before method call:

describe ".tick_all"   let(:instance) { factorygirl.create(:character) }   "invokes #tick every instance"     instance.should_receive(:tick)     character.tick_all   end end 

upd: code above doesn't work. variant?

describe ".tick_all"   "invokes #tick every instance"     character.any_instance.should_receive(:tick)     character.tick_all   end end 

upd2: aaand 1 more version:

describe ".tick_all"   "invokes #tick every instance"     tick_count = 0     character.any_instance.stub(:tick) { tick_count += 1 }     character.tick_all      tick_count.should == character.count     # or     # expect{ character.tick_all }.to change{tick_count}.by(character.count)   end end