scala - 如何显示 ScalaCheck 测试中抛出的异常的整个堆栈跟踪？

Question

我在运行 ScalaCheck sbt 中的测试，如果我的测试由于被测代码抛出异常而失败，则测试报告会显示失败的测试、抛出的异常和消息，但不会显示整个堆栈跟踪(注意下面仅是 Exception: java.lang.NullPointerException: exception 异常消息)。

[info] Loading global plugins from /Users/jacek/.sbt/0.13/plugins
[info] Set current project to scalacheck (in build file:/Users/jacek/sandbox/scalacheck/)
[info] Updating {file:/Users/jacek/sandbox/scalacheck/}scalacheck...
[info] Resolving jline#jline;2.11 ...
[info] Done updating.
[info] Compiling 1 Scala source to /Users/jacek/sandbox/scalacheck/target/scala-2.11/test-classes...
[info] ! String.throw exception: Exception raised on property evaluation.
[info] > ARG_0: ""
[info] > Exception: java.lang.NullPointerException: exception
[error] Error: Total 1, Failed 0, Errors 1, Passed 0
[error] Error during tests:
[error]     StringSpecification
[error] (test:test) sbt.TestsFailedException: Tests unsuccessful
[error] Total time: 5 s, completed Jun 25, 2014 3:25:47 AM

我找到了 https://groups.google.com/forum/#!msg/scalacheck/AGBgE_JlqpI/B2eSG84_QzYJ从 2008 年开始，它似乎报告了同样的问题，并表示应该在下一个版本中修复它。我目前使用的是最新版本 1.11.4。

我还找到了 http://www.scala-sbt.org/release/docs/Testing.html表示 sbt有一个 testOptions我认为使用起来似乎合理的键，而且我知道 ScalaTest 有一个完整堆栈跟踪设置， "-F" ，但这不适用于 ScalaCheck。即使是上页的例子， testOptions in Test += Tests.Argument(TestFrameworks.ScalaCheck, "-d", "-g")给我一个错误:

[error] Could not run test org.example.myproject.MyTestClass: java.lang.Exception: [1.1] failure: option name expected
[error] 
[error] -d -g
[error] ^

我如何使用这些测试参数，是否在任何地方都有这些参数的列表，最后，是否有可能从中获得堆栈跟踪，或者我是否在追逐红鲱鱼？

Answer 1

tl;博士 不支持 verbosity在 sbt 下使用已发布的 ScalaCheck 版本。您必须自己从源代码构建一个版本才能拥有该功能。

ScalaCheck 的可用选项在 Test Execution 中描述。 :

Available options:
  -workers, -w: Number of threads to execute in parallel for testing
  -minSize, -n: Minimum data generation size
  -verbosity, -v: Verbosity level
  -minSuccessfulTests, -s: Number of tests that must succeed in order to pass a property
  -maxDiscardRatio, -r: The maximum ratio between discarded and succeeded tests allowed before ScalaCheck stops testing a property. At least minSuccessfulTests will always be tested, though.
  -maxSize, -x: Maximum data generation size

org.scalacheck.util.Pretty的源代码告诉我们更多关于不同程度的vebosity:

implicit def prettyThrowable(e: Throwable) = Pretty { prms =>
  val strs = e.getStackTrace.map { st =>
    import st._
    getClassName+"."+getMethodName + "("+getFileName+":"+getLineNumber+")"
  }

  val strs2 =
    if(prms.verbosity <= 0) Array[String]()
    else if(prms.verbosity <= 1) strs.take(5)
    else strs

  e.getClass.getName + ": " + e.getMessage / strs2.mkString("\n")
}

所以， 0什么都不给， 1从堆栈跟踪中取出 5 行，而数字大于 1为您提供整个堆栈跟踪，如下所示:

➜  scalacheck  scala -cp .:/Users/jacek/.ivy2/cache/org.scalacheck/scalacheck_2.11/jars/scalacheck_2.11-1.11.4.jar StringSpecification -verbosity 3
+ String.startsWith: OK, passed 100 tests.
Elapsed time: 0.242 sec
! String.concatenate: Falsified after 0 passed tests.
> ARG_0: ""
> ARG_1: ""
Elapsed time: 0.003 sec
+ String.substring: OK, passed 100 tests.
Elapsed time: 0.126 sec
! String.throw exception: Exception raised on property evaluation.
> ARG_0: ""
> Exception: java.lang.NullPointerException: exception
StringSpecification$$anonfun$14.apply(StringSpecification.scala:19)
StringSpecification$$anonfun$14.apply(StringSpecification.scala:18)
scala.Function1$$anonfun$andThen$1.apply(Function1.scala:55)
org.scalacheck.Prop$$anonfun$forAllShrink$1$$anonfun$3.apply(Prop.scala:622
  )
org.scalacheck.Prop$$anonfun$forAllShrink$1$$anonfun$3.apply(Prop.scala:622
  )
org.scalacheck.Prop$.secure(Prop.scala:473)
org.scalacheck.Prop$$anonfun$forAllShrink$1.org$scalacheck$Prop$$anonfun$$r
  esult$1(Prop.scala:622)
org.scalacheck.Prop$$anonfun$forAllShrink$1.apply(Prop.scala:659)
org.scalacheck.Prop$$anonfun$forAllShrink$1.apply(Prop.scala:616)
org.scalacheck.Prop$$anon$1.apply(Prop.scala:309)
org.scalacheck.Test$.org$scalacheck$Test$$workerFun$1(Test.scala:335)
org.scalacheck.Test$$anonfun$org$scalacheck$Test$$worker$1$1.apply(Test.sca
  la:316)
org.scalacheck.Test$$anonfun$org$scalacheck$Test$$worker$1$1.apply(Test.sca
  la:316)
org.scalacheck.Test$.check(Test.scala:385)
org.scalacheck.Test$$anonfun$checkProperties$1.apply(Test.scala:402)
org.scalacheck.Test$$anonfun$checkProperties$1.apply(Test.scala:395)
scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala
  :245)
scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala
  :245)
scala.collection.immutable.List.foreach(List.scala:383)
scala.collection.generic.TraversableForwarder$class.foreach(TraversableForw
  arder.scala:35)
scala.collection.mutable.ListBuffer.foreach(ListBuffer.scala:45)
scala.collection.TraversableLike$class.map(TraversableLike.scala:245)
scala.collection.AbstractTraversable.map(Traversable.scala:104)
org.scalacheck.Test$.checkProperties(Test.scala:395)
org.scalacheck.Properties.mainRunner(Properties.scala:62)
org.scalacheck.Prop$class.main(Prop.scala:106)
org.scalacheck.Properties.main(Properties.scala:27)
StringSpecification.main(StringSpecification.scala:-1)
sun.reflect.NativeMethodAccessorImpl.invoke0(NativeMethodAccessorImpl.java:
  -2)
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:5
  7)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImp
  l.java:43)
java.lang.reflect.Method.invoke(Method.java:606)
scala.reflect.internal.util.ScalaClassLoader$$anonfun$run$1.apply(ScalaClas
  sLoader.scala:68)
scala.reflect.internal.util.ScalaClassLoader$class.asContext(ScalaClassLoad
  er.scala:31)
scala.reflect.internal.util.ScalaClassLoader$URLClassLoader.asContext(Scala
  ClassLoader.scala:99)
scala.reflect.internal.util.ScalaClassLoader$class.run(ScalaClassLoader.sca
  la:68)
scala.reflect.internal.util.ScalaClassLoader$URLClassLoader.run(ScalaClassL
  oader.scala:99)
scala.tools.nsc.CommonRunner$class.run(ObjectRunner.scala:22)
scala.tools.nsc.ObjectRunner$.run(ObjectRunner.scala:39)
scala.tools.nsc.CommonRunner$class.runAndCatch(ObjectRunner.scala:29)
scala.tools.nsc.ObjectRunner$.runAndCatch(ObjectRunner.scala:39)
scala.tools.nsc.MainGenericRunner.runTarget$1(MainGenericRunner.scala:72)
scala.tools.nsc.MainGenericRunner.process(MainGenericRunner.scala:94)
scala.tools.nsc.MainGenericRunner$.main(MainGenericRunner.scala:103)
scala.tools.nsc.MainGenericRunner.main(MainGenericRunner.scala:-1)
Elapsed time: 0.000 sec

sbt 的文档不正确是对的。没有 "-d", "-g"选项，我相信它们只是文档中的复制和粘贴错误。 It was already fixed in a pull request that's soon to be accepted.
verbosity在最新版本的 ScalaCheck 1.11.4 中，sbt 不支持该选项。以下是示例项目的整个构建定义。

build.sbt

scalaVersion := "2.11.1"

libraryDependencies += "org.scalacheck" %% "scalacheck" % "1.11.4" % "test"

testOptions in Test += Tests.Argument(TestFrameworks.ScalaCheck, "-verbosity", "3")

即使当 verbosity参数在 build.sbt 中正确指定，测试执行不会打印多于一行。

➜  scalacheck  xsbt test
[info] Loading global plugins from /Users/jacek/.sbt/0.13/plugins
[info] Set current project to scalacheck (in build file:/Users/jacek/sandbox/scalacheck/)
[info] + String.startsWith: OK, passed 100 tests.
[info] ! String.concatenate: Falsified after 0 passed tests.
[info] > ARG_0: ""
[info] > ARG_1: ""
[info] + String.substring: OK, passed 100 tests.
[info] ! String.throw exception: Exception raised on property evaluation.
[info] > ARG_0: ""
[info] > Exception: java.lang.NullPointerException: exception
[error] Error: Total 4, Failed 1, Errors 1, Passed 2
[error] Error during tests:
[error]     StringSpecification
[error] (test:test) sbt.TestsFailedException: Tests unsuccessful
[error] Total time: 1 s, completed Jun 25, 2014 2:57:08 AM

原因是 org.scalacheck.ScalaCheckFramework具有以下实现并假设 verbosity永远是 0 :

override def onTestResult(n: String, r: Test.Result) = {
  for (l <- loggers) {
    import Pretty._
    l.info(
      (if (r.passed) "+ " else "! ") + n + ": " + pretty(r, Params(0))
    )
  }
  handler.handle(asEvent((n,r)))
}

修复它的拉取请求已被 Support verbosity under sbt for TestFrameworks.ScalaCheck 下的 repo 接受。 .您必须使用 sbt publishLocal 自己构建 ScalaCheck在您克隆 repo 的目录中。不要忘记在 build.sbt 中使用 1.12.0-SNAPSHOT 版本拿起变化。