rspec/rspec-expectations — pull request #675 by myronmarston (2014-11-05 23:47:09+00:00)
Title: Make `yield_control` default to `at_least(:once)`.

Previously, it raised a confusing error when multiple
yields occurred:

> The yield_control matcher is not designed to be used with a
> method that yields multiple times. Use the yield_successive_args
> matcher for that case.

This was confusing because yield_control has supported multiple
yields for awhile. This also simplifies the implementation!