This document introduces Betamax, an HTTP mocking library for Java and Groovy. Betamax records HTTP interactions during tests and replays them on subsequent runs, making tests repeatable and reliable without requiring real HTTP calls. It works by intercepting requests and responses and matching them to pre-recorded "tapes", allowing tests to remain fast and isolated. The document provides examples of using Betamax with JUnit and Spock test frameworks and explains options for matching requests to tapes and controlling tape read/write modes.

1. βetamax
Rob Fletcher
Freeside Software / Energized Work

2. The impetus

3. HTTP connections in tests

4. Solution 1: Fake HTTP Server

5. Solution 2: Mock HTTP layer

6. Tests need to be…

7. Tests need to be…
Repeatable
Reliable
Realistic

8. Meanwhile in Ruby…
https://www.relishapp.com/myronmarston/vcr

9. Porting to JVM / Groovy

10. The Betamax Proxy

11. Using Betamax: JUnit
class TwitterServiceTest {
@Rule public Recorder recorder = new Recorder()
def twitterService = new TwitterService()
@Betamax(tape = "twitter ok")
@Test void searchesTweets() {
def tweets = twitterService.search("#cocktailclub")
assert tweets.size() == 20
assert tweets.text.every { it =~ /#cocktailclub/ }
}
}

12. Using Betamax: Spock
class TwitterServiceSpec extends Specification {
@Rule Recorder recorder = new Recorder()
def twitterService = new TwitterService()
@Betamax(tape = "twitter ok")
def "searches tweets"() {
when:
def tweets = twitterService.search("#cocktailclub")
then:
tweets.size() == 20
tweets.text.every { it =~ /#cocktailclub/ }
}
}

13. Matching Requests to Tapes
import static betamax.MatchRule.*
@Betamax()
@Betamax(match = host)
@Betamax(match = [method, uri, body])
@Betamax(match = [method, uri, headers])
@Betamax(match = [method, host, path])

14. Tape modes
import static betamax.TapeMode.*
@Betamax(mode = READ_WRITE)
@Betamax(mode = READ_ONLY)
@Betamax(mode = WRITE_ONLY)

15. Tape Files

16. Testing Practices

17. An example would be nice
right now…

18. The future of Betamax
github.com/robfletcher/betamax/issues

19. http://freeside.co/betamax
@betamaxtest
http://freeside.co
@rfletcherEW