TestBaton

testBaton.scala

import scala.collection.mutable.Buffer

/**
 * An object into a process under to test to, at test time, purposefully cause it to fail.
 *
 * A typical usage might be:
 * 
 * class SomeProcess(..., testBaton = NoopBaton() {
 *   def run() {
 *     val items = findSomeWorkItems()
 *     for (item <- items) {
 *       try {
 *         // real work
 *         testBaton.failIfTestingRecovery(item.getId)
 *       } catch {
 *         case e: Exception =>
 *           testBaton.recordRecoveredFailure(e)
 *       }
 *     }
 *   }
 * }
 */
trait TestBaton {
  def failIfTestingRecovery(o: Object): Unit

  def recordRecoveredFailure(e: Exception): Unit
}

/** The baton for production. */
class NoopBaton extends TestBaton {
  override def failIfTestingRecovery(o: Object) {}

  override def recordRecoveredFailure(e: Exception) {}
}

/** The baton for testing. */
class StubTestBaton extends TestBaton {

  var failOn: Option[Object] = None
  var numberOfIterations = 0
  val recoveredFailures = Buffer[Exception]()

  def assertNoErrors() {
    require(recoveredFailures == 0)
  }

  override def failIfTestingRecovery(o: Object) {
    if (failOn == Some(o)) {
      sys.error("Dummy failure")
    }
  }

  override def recordRecoveredFailure(e: Exception): Unit = {
    recoveredFailures += e
  }
}