org.scalatest.RecoverMethods.scala Maven / Gradle / Ivy
/*
* Copyright 2001-2013 Artima, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.scalatest
import scala.concurrent.Future
import scala.concurrent.ExecutionContext
import scala.reflect.ClassTag
import org.scalactic.source
import org.scalatest.exceptions.StackDepthException._
import org.scalactic.source
/**
* Offers two methods for transforming futures when exceptions are expected.
*
*
* This trait offers two methods for testing for expected exceptions in the context of
* futures: recoverToSucceededIf and recoverToExceptionIf.
* Because this trait is mixed into trait AsyncTestSuite, both of its methods are
* available by default in any async-style suite.
*
*
*
* If you just want to ensure that a future fails with a particular exception type, and do
* not need to inspect the exception further, use recoverToSucceededIf:
*
*
*
* recoverToSucceededIf[IllegalStateException] { // Result type: Future[Assertion]
* emptyStackActor ? Peek
* }
*
*
*
* The recoverToSucceededIf method performs a job similar to
* assertThrows, except
* in the context of a future. It transforms a Future of any type into a
* Future[Assertion] that succeeds only if the original future fails with the specified
* exception. Here's an example in the REPL:
*
*
*
* scala> import org.scalatest.RecoverMethods._
* import org.scalatest.RecoverMethods._
*
* scala> import scala.concurrent.Future
* import scala.concurrent.Future
*
* scala> import scala.concurrent.ExecutionContext.Implicits.global
* import scala.concurrent.ExecutionContext.Implicits.global
*
* scala> recoverToSucceededIf[IllegalStateException] {
* | Future { throw new IllegalStateException }
* | }
* res0: scala.concurrent.Future[org.scalatest.Assertion] = ...
*
* scala> res0.value
* res1: Option[scala.util.Try[org.scalatest.Assertion]] = Some(Success(Succeeded))
*
*
*
* Otherwise it fails with an error message similar to those given by assertThrows:
*
*
*
* scala> recoverToSucceededIf[IllegalStateException] {
* | Future { throw new RuntimeException }
* | }
* res2: scala.concurrent.Future[org.scalatest.Assertion] = ...
*
* scala> res2.value
* res3: Option[scala.util.Try[org.scalatest.Assertion]] =
* Some(Failure(org.scalatest.exceptions.TestFailedException: Expected exception
* java.lang.IllegalStateException to be thrown, but java.lang.RuntimeException
* was thrown))
*
* scala> recoverToSucceededIf[IllegalStateException] {
* | Future { 42 }
* | }
* res4: scala.concurrent.Future[org.scalatest.Assertion] = ...
*
* scala> res4.value
* res5: Option[scala.util.Try[org.scalatest.Assertion]] =
* Some(Failure(org.scalatest.exceptions.TestFailedException: Expected exception
* java.lang.IllegalStateException to be thrown, but no exception was thrown))
*
*
*
* The recoverToExceptionIf method differs from the recoverToSucceededIf in
* its behavior when the assertion succeeds: recoverToSucceededIf yields a Future[Assertion],
* whereas recoverToExceptionIf yields a Future[T], where T is the
* expected exception type.
*
*
*
* recoverToExceptionIf[IllegalStateException] { // Result type: Future[IllegalStateException]
* emptyStackActor ? Peek
* }
*
*
*
* In other words, recoverToExpectionIf is to
* intercept as
* recovertToSucceededIf is to assertThrows. The first one allows you to perform further
* assertions on the expected exception. The second one gives you a result type that will satisfy the type checker
* at the end of the test body. Here's an example showing recoverToExceptionIf in the REPL:
*
*
*
* scala> val futureEx =
* | recoverToExceptionIf[IllegalStateException] {
* | Future { throw new IllegalStateException("hello") }
* | }
* futureEx: scala.concurrent.Future[IllegalStateException] = ...
*
* scala> futureEx.value
* res6: Option[scala.util.Try[IllegalStateException]] =
* Some(Success(java.lang.IllegalStateException: hello))
*
* scala> futureEx map { ex => assert(ex.getMessage == "world") }
* res7: scala.concurrent.Future[org.scalatest.Assertion] = ...
*
* scala> res7.value
* res8: Option[scala.util.Try[org.scalatest.Assertion]] =
* Some(Failure(org.scalatest.exceptions.TestFailedException: "[hello]" did not equal "[world]"))
*
*
* @author Bill Venners
*/
trait RecoverMethods {
/**
* Transforms a future of any type into a Future[T], where T is a given
* expected exception type, which succeeds if the given future
* completes with a Failure containing the specified exception type.
*
*
* See the main documentation for this trait for more detail and examples.
*
*
* @param future A future of any type, which you expect to fail with an exception of the specified type T
* @return a Future[T] containing on success the expected exception, or containing on failure
* a TestFailedException
*/
def recoverToExceptionIf[T <: AnyRef](future: Future[Any])(implicit classTag: ClassTag[T], exCtx: ExecutionContext, pos: source.Position): Future[T] = {
val clazz = classTag.runtimeClass
future.failed.transform(
ex =>
if (!clazz.isAssignableFrom(ex.getClass)) {
val message = Resources.wrongException(clazz.getName, ex.getClass.getName)
throw newAssertionFailedExceptionForRecover(Some(message), Some(ex), pos)
}
else ex.asInstanceOf[T]
,
ex => {
val message = Resources.exceptionExpected(clazz.getName)
throw newAssertionFailedExceptionForRecover(Some(message), None, pos)
}
)
}
/**
* Transforms a future of any type into a Future[Assertion] that succeeds if the future
* completes with a Failure containing the specified exception type.
*
*
* See the main documentation for this trait for more detail and examples.
*
*
* @param future A future of any type, which you expect to fail with an exception of the specified type T
* @return a Future[Assertion] containing on success the Succeeded singleton, or containing on failure
* a TestFailedException
*/
def recoverToSucceededIf[T <: AnyRef](future: Future[Any])(implicit classTag: ClassTag[T], exCtx: ExecutionContext, pos: source.Position): Future[Assertion] = {
val clazz = classTag.runtimeClass
future.failed.transform(
rawEx => {
val ex =
rawEx match {
case execEx: java.util.concurrent.ExecutionException => execEx.getCause
case other => other
}
if (!clazz.isAssignableFrom(ex.getClass)) {
val message = Resources.wrongException(clazz.getName, ex.getClass.getName)
throw newAssertionFailedExceptionForRecover(Some(message), Some(ex), pos)
}
else Succeeded
},
ex => {
val message = Resources.exceptionExpected(clazz.getName)
throw newAssertionFailedExceptionForRecover(Some(message), None, pos)
}
)
}
private[scalatest] def newAssertionFailedExceptionForRecover(optionalMessage: Option[String], optionalCause: Option[Throwable], pos: source.Position): Throwable =
new exceptions.TestFailedException(toExceptionFunction(optionalMessage), optionalCause, pos)
}
/**
* Companion object that facilitates the importing of RecoverMethods's method as
* an alternative to mixing it in. One use case is to import RecoverMethods's method so you can use
* it in the Scala interpreter.
*
* @author Bill Venners
*/
object RecoverMethods extends RecoverMethods