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Rack::Test is a small, simple testing API for Rack apps.


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Gem Version



Rack::Test is a small, simple testing API for Rack apps. It can be used on its own or as a reusable starting point for Web frameworks and testing libraries to build on.


  • Allows for submitting requests and testing responses
  • Maintains a cookie jar across requests
  • Supports request headers used for subsequent requests
  • Follow redirects when requested


These examples use test/unit but it's equally possible to use rack-test with other testing frameworks such as minitest or rspec.

require "test/unit"
require "rack/test"
require "json"

class HomepageTest < Test::Unit::TestCase
  include Rack::Test::Methods

  def app
    lambda { |env| [200, {'content-type' => 'text/plain'}, ['All responses are OK']] }

  def test_response_is_ok
    # Optionally set headers used for all requests in this spec:
    #header 'accept-charset', 'utf-8'

    # First argument is treated as the path
    get '/'

    assert last_response.ok?
    assert_equal 'All responses are OK', last_response.body

  def delete_with_url_params_and_body
    # First argument can have a query string
    # Second argument is used as the parameters for the request, which will be
    # included in the request body for non-GET requests.
    delete '/?foo=bar', JSON.generate('baz' => 'zot')

  def post_with_json
    # Third argument is the rack environment to use for the request.  The following
    # entries in the submitted rack environment are treated specially (in addition
    # to options supported by `Rack::MockRequest#env_for`:
    # :cookie : Set a cookie for the current session before submitting the request.
    # :query_params : Set parameters for the query string (as opposed to the body).
    #                 Value should be a hash of parameters.
    # :xhr : Set HTTP_X_REQUESTED_WITH env key to XMLHttpRequest.
    post(uri, JSON.generate('baz' => 'zot'), 'CONTENT_TYPE' => 'application/json')

rack-test will test the app returned by the app method. If you are loading middleware in a file, and want to test that, you should load the Rack app created from the file:

OUTER_APP = Rack::Builder.parse_file("").first

class TestApp < Test::Unit::TestCase
  include Rack::Test::Methods

  def app

  def test_root
    get "/"
    assert last_response.ok?


To install the latest release as a gem:

gem install rack-test

Or add to your Gemfile:

gem 'rack-test'


Contributions are welcome. Please make sure to:

  • Use a regular forking workflow
  • Write tests for the new or changed behaviour
  • Provide an explanation/motivation in your commit message / PR message
  • Ensure is updated


  • Contributions from Bryan Helmkamp, Jeremy Evans, Simon Rozet, and others
  • Much of the original code was extracted from Merb 1.0's request helper


rack-test is released under the MIT License.

Supported platforms

  • Ruby 2.0+
  • JRuby 9.1+


  • Bump VERSION in lib/rack/test/version.rb
  • Ensure is up-to-date, including correct version and date
  • git commit . -m 'Release $VERSION'
  • git push
  • git tag -a -m 'Tag the $VERSION release' $VERSION
  • git push --tags
  • gem build rack-test.gemspec
  • gem push rack-test-$VERSION.gem
  • Add a discussion post for the release