Webmock: EOF 오류

Test/Unit 및 em-http-request와 함께 WebMock을 사용하면 다음 오류가 발생합니다.

EOFError: end of file reached
/Users/harry/.rvm/gems/ruby-1.9.1-p378/gems/webmock-1.3.4/lib/webmock/response.rb:117:in `read_raw_response'
/Users/harry/.rvm/gems/ruby-1.9.1-p378/gems/webmock-1.3.4/lib/webmock/response.rb:21:in `initialize'
/Users/harry/.rvm/gems/ruby-1.9.1-p378/gems/webmock-1.3.4/lib/webmock/response.rb:13:in `new'
/Users/harry/.rvm/gems/ruby-1.9.1-p378/gems/webmock-1.3.4/lib/webmock/response.rb:13:in `response_for'
/Users/harry/.rvm/gems/ruby-1.9.1-p378/gems/webmock-1.3.4/lib/webmock/request_stub.rb:21:in `block in to_return'
/Users/harry/.rvm/gems/ruby-1.9.1-p378/gems/webmock-1.3.4/lib/webmock/request_stub.rb:21:in `map'
/Users/harry/.rvm/gems/ruby-1.9.1-p378/gems/webmock-1.3.4/lib/webmock/request_stub.rb:21:in `to_return'
test/test_changes.rb:97:in `block (2 levels) in <class:TestCouchChanges>'
/Users/harry/.rvm/gems/ruby-1.9.1-p378/gems/eventmachine-0.12.11/lib/eventmachine.rb:195:in `call'
/Users/harry/.rvm/gems/ruby-1.9.1-p378/gems/eventmachine-0.12.11/lib/eventmachine.rb:195:in `run_machine'
/Users/harry/.rvm/gems/ruby-1.9.1-p378/gems/eventmachine-0.12.11/lib/eventmachine.rb:195:in `run'
test/test_changes.rb:93:in `block in <class:TestCouchChanges>'