collect_deprecations

# File activesupport/lib/active_support/testing/deprecation.rb, line 23
        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