Test helper method to perform multiple assert_difference calls easily.

assert_differences

# Example
assert_differences 'Initiative.count' => 1, 'Role.count' => -1, 'Phase.count' => 0 do
  @initiative.to_template!
end

def assert_differences(collection = {}, &block)    
  yield and return if collection.empty? 

  collection.shift.tap do |diff|
    assert_differences(collection){ assert_difference(diff.first, diff.last, &block) }
  end
end