Allow Unused HTTP Interactions

If set to false, this cassette option will cause VCR to raise an error when a cassette is ejected and there are unused HTTP interactions remaining, unless there is already an exception unwinding the callstack.

It verifies that all requests included in the cassette were made, and allows VCR to function a bit like a mock object at the HTTP layer.

The option defaults to true (mostly for backwards compatibility).

Background

Given a file named "vcr_config.rb" with:

require 'vcr'

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

And 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: 
      - "5"
    body: 
      encoding: UTF-8
      string: Hello
    http_version: "1.1"
  recorded_at: Tue, 01 Nov 2011 04:58:44 GMT
recorded_with: VCR 2.0.0

Unused HTTP interactions are allowed by default

Given a file named "allowed_by_default.rb" with:

require 'vcr_config'

VCR.use_cassette("example") do
  # no requests
end

When I run ruby allowed_by_default.rb

Then it should pass.

Error raised if option is false and there are unused interactions

Given a file named "disallowed_with_no_requests.rb" with:

require 'vcr_config'

VCR.use_cassette("example", :allow_unused_http_interactions => false) do
  # no requests
end

When I run ruby disallowed_with_no_requests.rb

Then it should fail with an error like:

There are unused HTTP interactions left in the cassette:
  - [get http://example.com/foo] => [200 "Hello"]

No error raised if option is false and all interactions are used

Given a file named "disallowed_with_all_requests.rb" with:

require 'vcr_config'

VCR.use_cassette("example", :allow_unused_http_interactions => false) do
  Net::HTTP.get_response(URI("http://example.com/foo"))
end

When I run ruby disallowed_with_all_requests.rb

Then it should pass.

Does not silence other errors raised in use_cassette block

Given a file named "does_not_silence_other_errors.rb" with:

require 'vcr_config'

VCR.use_cassette("example", :allow_unused_http_interactions => false) do
  raise "boom"
end

When I run ruby does_not_silence_other_errors.rb

Then it should fail with "boom"

And the output should not contain "There are unused HTTP interactions".