# File actionpack/lib/action_dispatch/testing/assertions/response.rb, line 55
def assert_redirected_to(options = {}, message=nil)
  assert_response(:redirect, message)
  return true if options === @response.location

  redirect_is       = normalize_argument_to_redirection(@response.location)
  redirect_expected = normalize_argument_to_redirection(options)

  message ||= "Expected response to be a redirect to <#{redirect_expected}> but was a redirect to <#{redirect_is}>"
  assert_operator redirect_expected, :===, redirect_is, message
end

Assert that the redirection options passed in match those of the redirect called in the latest action. This match can be partial, such that assert_redirected_to(controller: "weblog") will also match the redirection of redirect_to(controller: "weblog", action: "show") and so on.

# assert that the redirection was to the "index" action on the WeblogController
assert_redirected_to controller: "weblog", action: "index"

# assert that the redirection was to the named route login_url
assert_redirected_to login_url

# assert that the redirection was to the url for @customer
assert_redirected_to @customer

# asserts that the redirection matches the regular expression
assert_redirected_to %r(\Ahttp://example.org)

# File actionpack/lib/action_dispatch/testing/assertions/response.rb, line 22
def assert_response(type, message = nil)
  message ||= "Expected response to be a <#{type}>, but was <#{@response.response_code}>"

  if Symbol === type
    if [:success, :missing, :redirect, :error].include?(type)
      assert @response.send("#{type}?"), message
    else
      code = Rack::Utils::SYMBOL_TO_STATUS_CODE[type]
      if code.nil?
        raise ArgumentError, "Invalid response type :#{type}"
      end
      assert_equal code, @response.response_code, message
    end
  else
    assert_equal type, @response.response_code, message
  end
end

Asserts that the response is one of the following types:

• :success - Status code was in the 200-299 range

• :redirect - Status code was in the 300-399 range

• :missing - Status code was 404

• :error - Status code was in the 500-599 range

You can also pass an explicit status number like assert_response(501) or its symbolic equivalent assert_response(:not_implemented). See Rack::Utils::SYMBOL_TO_STATUS_CODE for a full list.

# assert that the response was a redirection
assert_response :redirect

# assert that the response code was status code 401 (unauthorized)
assert_response 401