collect_deprecations

# File activesupport/lib/active_support/testing/deprecation.rb, line 22
      def collect_deprecations
        old_behavior = ActiveSupport::Deprecation.behavior
        deprecations = []
        ActiveSupport::Deprecation.behavior = Proc.new do |message, callstack|
          deprecations << message
        end
        result = yield
        [result, deprecations]
      ensure
        ActiveSupport::Deprecation.behavior = old_behavior
      end