Playback Repeats

By default, each response in a cassette can only be matched and played back once while the cassette is in use (it can, of course, be re-used in multiple tests, each of which should use the cassette separately). Note that this is a change from the behavior in VCR 1.x. The old behavior occurred because of how WebMock behave internally and was not intended. Repeats create less accurate tests since the real HTTP server may not necessarily return the same response when identical requests are made in sequence.

If you want to allow playback repeats, VCR has a cassette option for this:

  :allow_playback_repeats => true

Responses do not repeat by default

Given a previously recorded cassette file "cassettes/example.yml" with:

--- 
http_interactions: 
- request: 
    method: get
    uri: http://example.com/foo
    body: 
      encoding: UTF-8
      string: ""
    headers: {}
  response: 
    status: 
      code: 200
      message: OK
    headers: 
      Content-Length: 
      - "10"
    body: 
      encoding: UTF-8
      string: Response 1
    http_version: "1.1"
  recorded_at: Tue, 01 Nov 2011 04:58:44 GMT
- request: 
    method: get
    uri: http://example.com/foo
    body: 
      encoding: UTF-8
      string: ""
    headers: {}
  response: 
    status: 
      code: 200
      message: OK
    headers: 
      Content-Length: 
      - "10"
    body: 
      encoding: UTF-8
      string: Response 2
    http_version: "1.1"
  recorded_at: Tue, 01 Nov 2011 04:58:44 GMT
recorded_with: VCR 2.0.0

And a file named "playback_repeats.rb" with:

include_http_adapter_for("net/http")

require 'vcr'

VCR.configure do |c|
  c.hook_into :webmock
  c.cassette_library_dir = 'cassettes'
end

puts "== With :allow_playback_repeats =="
VCR.use_cassette('example', :allow_playback_repeats => true) do
  puts response_body_for(:get, 'http://example.com/foo')
  puts response_body_for(:get, 'http://example.com/foo')
  puts response_body_for(:get, 'http://example.com/foo')
end

puts "\n== Without :allow_playback_repeats =="
VCR.use_cassette('example') do
  puts response_body_for(:get, 'http://example.com/foo')
  puts response_body_for(:get, 'http://example.com/foo')
  puts response_body_for(:get, 'http://example.com/foo')
end

When I run ruby playback_repeats.rb

Then it should fail with "An HTTP request has been made that VCR does not know how to handle"

And the output should contain:

== With :allow_playback_repeats ==
Response 1
Response 2
Response 2

== Without :allow_playback_repeats ==
Response 1
Response 2