module ActiveSupport::Testing::Deprecation

def assert_deprecated(match = nil, deprecator = nil, &block)
  result, warnings = collect_deprecations(deprecator, &block)
  assert !warnings.empty?, "Expected a deprecation warning within the block but received none"
  if match
    match = Regexp.new(Regexp.escape(match)) unless match.is_a?(Regexp)
    assert warnings.any? { |w| match.match?(w) }, "No deprecation warning matched #{match}: #{warnings.join(', ')}"
  end
  result
end

def assert_not_deprecated(deprecator = nil, &block)
  result, deprecations = collect_deprecations(deprecator, &block)
  assert deprecations.empty?, "Expected no deprecation warning within the block but received #{deprecations.size}: \n  #{deprecations * "\n  "}"
  result
end

def collect_deprecations(deprecator = nil)
  deprecator ||= ActiveSupport::Deprecation
  old_behavior = deprecator.behavior
  deprecations = []
  deprecator.behavior = Proc.new do |message, callstack|
    deprecations << message
  end
  result = yield
  [result, deprecations]
ensure
  deprecator.behavior = old_behavior
end