Question

import org.scalatest.{ FlatSpec, Matchers, ParallelTestExecution }
import org.scalatest.concurrent.ScalaFutures
import org.apache.thrift.TApplicationException

class Test extends FlatSpec with Matchers with ScalaFutures with ParallelTestExecution {
  it should "throw org.apache.thrift.TApplicationException for invalid Ids" in {
    val future: Future[Response] = ThriftClient.thriftRequest
    whenReady(future) {
      res => {
       intercept[TApplicationException] {
       }
      }
    }
  }
}

问题：如何在没有阻止的情况下断言期货中的预期失败？以上操作不起作用，在intercept块之前抛出异常。

Answer 1

我知道这可能有点迟了，但ScalaTest通过混合ScalaFutures特性或直接在测试函数中使用它，提供了开箱即用的这个功能（我相信自版本2）。看哪！

test("some test") {
  val f: Future[Something] = someObject.giveMeAFuture
  ScalaFutures.whenReady(f.failed) { e =>
    e shouldBe a [SomeExceptionType]
  }
}

或者您可以在那里执行其他一些断言。基本上，如果你的未来没有像你期望的那样失败，那么测试就会失败。如果失败，但抛出不同的异常，则测试将失败。好，易于！ =]

厚脸皮编辑：

您还可以使用此方法测试任何返回未来的内容：

test("some test") {
  val f: Future[Something] = someObject.giveMeAFuture
  ScalaFutures.whenReady(f) { s =>
    // run assertions against the object returned in the future
  }
}

Answer 2

这也被隐藏在评论中，但是Scalatest的FutureValues mixin让你满意。

只需使用f.failed.futureValue shouldBe an[TApplicationException]

即可

Answer 3

注意：留下这个答案是因为OP发现它有用，但是对于Scala Futures，请看其他答案。

这有点花洒，但来自Waiter的{{1}}：

AsyncAssertions

给定的

import org.scalatest.{ FlatSpec, Matchers, ParallelTestExecution }
import org.scalatest.concurrent.{ ScalaFutures, AsyncAssertions, PatienceConfiguration }
import concurrent.Future
import concurrent.ExecutionContext.Implicits._
import util._ 

class Test extends FlatSpec with Matchers with ScalaFutures with ParallelTestExecution with AsyncAssertions {
  it should "throw for invalid Ids" in {
    val f: Future[Int] = new Goof().goof
    val w = new Waiter
    f onComplete {
      case Failure(e) => w(throw e); w.dismiss()
      case Success(_) => w.dismiss()
    }
    intercept[UnsupportedOperationException] {
      w.await
    }
  }
}

换句话说，

import concurrent.Future
import concurrent.ExecutionContext.Implicits._

class Goof {
  def goof(delay: Int = 1): Future[Int] = Future {
    Thread sleep delay * 1000L
    throw new UnsupportedOperationException
  } 
  def goofy(delay: Int = 1): Future[Int] = Future {
    Thread sleep delay * 1000L
    throw new NullPointerException
  } 
  def foog(delay: Int = 1): Future[Int] = Future {
    Thread sleep delay * 1000L
    7
  }
}

或者，如果您有多个期货，并且您希望第一个不合格的未来未通过测试：

class Test extends FlatSpec with Matchers with ScalaFutures with ParallelTestExecution with AsyncAssertions {
  it should "throw for invalid Ids" in {
    val f: Future[Int] = new Goof().goof
    import Helper._
    f.failing[UnsupportedOperationException] 
  }
}

object Helper {
  implicit class Failing[A](val f: Future[A]) extends Assertions with AsyncAssertions {
    def failing[T <: Throwable](implicit m: Manifest[T]) = {
      val w = new Waiter
      f onComplete {
        case Failure(e) => w(throw e); w.dismiss()
        case Success(_) => w.dismiss()
      }
      intercept[T] {
        w.await
      }
    } 
  } 
}

使用

trait FailHelper extends Assertions with AsyncAssertions with PatienceConfiguration {
  def failingWith[T <: Throwable : Manifest](fs: Future[_]*)(implicit p: PatienceConfig) {
    val count = new java.util.concurrent.atomic.AtomicInteger(fs.size)
    val w = new Waiter
    for (f <- fs) f onComplete {
      case Success(i) =>
        w(intercept[T](i))
        println(s"Bad success $i")
        w.dismiss()
      case Failure(e: T) =>
        println(s"Failed $e OK, count ${count.get}")
        w(intercept[T](throw e))
        if (count.decrementAndGet == 0) w.dismiss()
      case Failure(e) =>
        println(s"Failed $e Bad")
        w(intercept[T](throw e))
        w.dismiss()
    }
    w.await()(p)
  }
}

受this unloved answer的启发。

Answer 4

ScalaTest 3.0添加async versions of the spec traits，如AsyncFreeSpec：

import org.scalatest.{AsyncFlatSpec, Matchers}
import scala.concurrent.Future

class ScratchSpec extends AsyncFlatSpec with Matchers  {

    def thriftRequest = Future { throw new Exception() }

    it should "throw exception" in {
        recoverToSucceededIf[Exception] {
            thriftRequest
        }
    }
}

Answer 5

您还可以尝试一些简单而简短的

test("some test throwing SQL Exception") {
      val f: Future[Something] = someObject.giveMeAFuture
      recoverToSucceededIf[SQLException](f)
    }

Answer 6

除了 Brian Low的答案，我为recoverToSucceededIf找到了一个很好的解释。所有 Async样式（从 ScalaTest 3 起）均可用：

可以通过两种方式测试失败的期货：使用recoverToSucceededIf或recoverToExceptionIf

recoverToSucceededIf用于声明将来终止于的异常类型：

"return UserNotFoundException" when {
       "the user does not exist" in {
         recoverToSucceededIf[UserNotFoundException](userService.findUser("1"))
       }
     }

recoverToExceptionIf很有用：

"return UserAlreadyExistsException" when {
     "adding a user with existing username" in {
       recoverToExceptionIf[UserAlreadyExistsException] {
         userService.addUser(user)
       }.map { ex =>
         ex.message shouldBe s"User with username: $username already exists!"
       }
     }
   }

查看Tudor Zgureanu — What's new in ScalaTest 3上的整个博客

ScalaTest：在失败的期货中断言异常（非阻塞）

6 个答案:

注意：留下这个答案是因为OP发现它有用，但是对于Scala Futures，请看其他答案。