and_iterates/and_yields should handle enumerator chains

[npepinpe]

With version 2.3.5, using the following:

flexmock(collection).should_receive(:each_batch).and_iterates(%w[a b c], %[d e f])
collection.each_batch.each_with_index do |batch, index|
   ...
end

Produces the following exception:

FlexMock::MockError: No Block given to mock with 'and_yield' expectation

Intuitively, I would have expected the above code to simply work. I'm not entirely sure how feasible it would be, and there are work-arounds, but it would be a nice to have.

[doudou]

Let's forget about the implementation (which is probably somehow feasible), and discuss the feature first.

I see the point, especially given that I'm also prone to providing all my #each methods with the "return an enumerator if no block is given" pattern.

However, this is not a feature of the language... The 'yield-to-enumerator' conversion relies on code within the method, and I would assume that existing users of and_yields/and_iterates actually rely on this check. I would prefer a syntax that allows for both usage patterns. I'll need to think about it ... Suggestions ?