VCR

Record your test suite's HTTP interactions and replay them during future test runs for fast, deterministic, accurate tests.

Synopsis

require 'rubygems'
require 'test/unit'
require 'vcr'

VCR.configure do |c|
  c.cassette_library_dir = 'fixtures/vcr_cassettes'
  c.hook_into :webmock # or :fakeweb
end

class VCRTest < Test::Unit::TestCase
  def test_example_dot_com
    VCR.use_cassette('synopsis') do
      response = Net::HTTP.get_response(URI('http://www.iana.org/domains/example/'))
      assert_match /Example Domains/, response.body
    end
  end
end

Run this test once, and VCR will record the http request to fixtures/vcr_cassettes/synopsis.yml. Run it again, and VCR will replay the response from iana.org when the http request is made. This test is now fast (no real HTTP requests are made anymore), deterministic (the test will continue to pass, even if you are offline, or iana.org goes down for maintenance) and accurate (the response will contain the same headers and body you get from a real request).

Features

Automatically records and replays your HTTP interactions with minimal setup/configuration code.
Supports and works with the HTTP stubbing facilities of multiple libraries. Currently, the following are supported:
- FakeWeb
- WebMock
- Typhoeus
- Faraday
- Excon
Supports multiple HTTP libraries:
- Patron (when using WebMock)
- Curb (when using WebMock -- only supports Curl::Easy at the moment)
- HTTPClient (when using WebMock)
- em-http-request (when using WebMock)
- Net::HTTP (when using FakeWeb and WebMock)
- Typhoeus (Typhoeus::Hydra, but not Typhoeus::Easy or Typhoeus::Multi)
- Excon
- Faraday
- And of course any library built on Net::HTTP, such as Mechanize, HTTParty or Rest Client.
Request matching is configurable based on HTTP method, URI, host, path, body and headers, or you can easily implement a custom request matcher to handle any need.
The same request can receive different responses in different tests--just use different cassettes.
The recorded requests and responses are stored on disk in a serialization format of your choice (currently YAML and JSON are built in, and you can easily implement your own custom serializer) and can easily be inspected and edited.
Dynamic responses are supported using ERB.
Automatically re-records cassettes on a configurable regular interval to keep them fresh and current.
Disables all HTTP requests that you don't explicitly allow.
Simple cucumber integration is provided using tags.
Includes convenient RSpec macro and integration with RSpec 2 metadata.
Known to work well with many popular ruby libraries including RSpec 1 & 2, Cucumber, Test::Unit, Capybara, Mechanize, Rest-Client and HTTParty.
Includes Rack and Faraday middleware.

Usage

Browse the documentation for usage info.

The VCR talk given at Philly.rb also contains good usage info.

Release Policy

VCR follows the principles of semantic versioning. The cucumber features define VCR's public API. Patch level releases contain only bug fixes. Minor releases contain backward-compatible new features. Major new releases contain backwards-incompatible changes to the public API.

Ruby Interpreter Compatibility

VCR has been tested on the following ruby interpreters:

MRI 1.8.7
MRI 1.9.2
REE 1.8.7
JRuby
Rubinius

Development

Source hosted on GitHub.
Direct questions and discussions to the mailing list.
Report issues on GitHub Issues.
Pull requests are very welcome! Please include spec and/or feature coverage for every patch, and create a topic branch for every separate change you make.
See the Contributing guide for instructions on running the specs and features.
Documentation is generated with YARD (cheat sheet). To generate while developing:

yard server --reload

If you find VCR useful, please recommend me on working with rails.

Thanks

Aslak Hellesøy for Cucumber.
Bartosz Blimke for WebMock.
Chris Kampmeier for FakeWeb.
Chris Young for NetRecorder, the inspiration for VCR.
David Balatero for help with Typhoeus support.
Wesley Beary for help with Excon support.

Thanks also to the following people who have contributed patches or helpful suggestions:

Similar Libraries

Betamax (Groovy)
Ephemeral Response (Ruby)
Mimic (PHP/Kohana)
Net::HTTP Spy (Ruby)
NetRecorder (Ruby)
Stale Fish (Ruby)
WebFixtures (Ruby)

mrmargolis/vcr

VCR