If you stub a method or set expectations with should_receive these stubbed methods may also yield blocks. This is handy if the returning object is receiving a block call.
Consider this, where you cannot say and_return [] because of the block:
def crawl_messages
Message.find_in_batches do |messages|
messages.each(&:crawl)
end
end
It works similar to and_return -- just use
and_yield
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:
describe '#crawl_messages' do
it 'should process messages in batches so the server stays alive' do
message = stub
message.should_receive(:crawl)
Message.should_receive(:find_in_batches).and_yield([message])
subject.crawl_messages
end
end
You can also combine and_yield with and_return. Mind the order:
item = stub('a block')
subject.should_receive(:something).and_yield(item).and_return 'result'
Yielding multiple times
You can even chain multiple and_yield statements to yield the block multiple times with different arguments:
subject.should_receive(:something).and_yield(item1).and_yield(item2)
Posted by Arne Hartherz to makandra dev (2011-07-04 13:50)