Mock with multiple frameworks based on metadata. In reply to https://twitter.com/_solnic_/status/334682956771778560

spec_helper.rb

# This is totally untested, but something like this should work...
module MultipleMockFrameworksAdapters
  extend Forwardable
  def_delegators :mock_framework_for_current_example,
                 # these are the 3 methods your adapter needs
                 :setup_mocks_for_rspec,
                 :verify_mocks_for_rspec,
                 :teardown_mocks_for_rspec

  def mock_framework_for_current_example
    case $current_rspec_example.metadata[:mock_with]
      when :mocha
        # Unfortunately, in https://github.com/rspec/rspec-core/tree/master/lib/rspec/core/mocking
        # Each adapter is defined as the same module, so you can't just delegate to the existing
        # ones here.  That should be fixed, though; I'd happily accept a PR addressing that!
        # So, you'll need to define these based on the ones in the directory linked to above.
        MochaAdapter
      else
        RSpecMocksAdapter
    end
  end
end

RSpec.configure do |rspec|
  # Tell rspec to use your adapter
  rspec.mock_with MultipleMockFrameworksAdapters

  # Finally, make the current example globally available so you can branch on its
  # metadata in your adapter above.
  rspec.before(:each) do
    $current_rspec_example = example
  end
end