zio assert 代数数据类型的子类型

编程问答 2022-05-14

问题描述

给定的代数数据类型

sealed trait Result
case object Success extends Result
case class MyFailure(details: String) extends Result

如何在 zio-test 中断言特定值是 Failure 并且其详细信息包含特定子字符串？

例如，如何断言 r 下面是一个失败且带有 "mana" 子字符串？

val r: Result = MyFailure("not enough mana")

解决方法

假设结果是由一个 effect 产生的（换句话说，它被 ZIO 包裹了），你可以使用 mapError 来在失败的情况下使用 details，然后使用 {{1 有效地断言}} 和 assertM：

fails(containsString)
,

可以通过 java.io.EOFException at java.base/java.io.ObjectInputStream$PeekInputStream.readFully(ObjectInputStream.java:2932) at java.base/java.io.ObjectInputStream$BlockDataInputStream.readShort(ObjectInputStream.java:3427) at java.base/java.io.ObjectInputStream.readStreamHeader(ObjectInputStream.java:962) at java.base/java.io.ObjectInputStream.<init>(ObjectInputStream.java:405) at model.LevelSaver.getHistory(LevelSaver.java:41) at view.PlayingMenu$1.handle(PlayingMenu.java:150) at view.PlayingMenu$1.handle(PlayingMenu.java:87) at javafx.base/com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:86) at javafx.base/com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:234) at javafx.base/com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191) at javafx.base/com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59) at javafx.base/com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58) at javafx.base/com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114) at javafx.base/com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56) at javafx.base/com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114) at javafx.base/com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56) at javafx.base/com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114) at javafx.base/com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74) at javafx.base/com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:54) at javafx.base/javafx.event.Event.fireEvent(Event.java:198) at javafx.graphics/javafx.scene.Scene$KeyHandler.process(Scene.java:4064) at javafx.graphics/javafx.scene.Scene.processKeyEvent(Scene.java:2123) at javafx.graphics/javafx.scene.Scene$ScenePeerListener.keyEvent(Scene.java:2591) at javafx.graphics/com.sun.javafx.tk.quantum.GlassViewEventHandler$KeyEventNotification.run(GlassViewEventHandler.java:217) at javafx.graphics/com.sun.javafx.tk.quantum.GlassViewEventHandler$KeyEventNotification.run(GlassViewEventHandler.java:149) at java.base/java.security.AccessController.doPrivileged(AccessController.java:391) at javafx.graphics/com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleKeyEvent$1(GlassViewEventHandler.java:248) at javafx.graphics/com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:412) at javafx.graphics/com.sun.javafx.tk.quantum.GlassViewEventHandler.handleKeyEvent(GlassViewEventHandler.java:247) at javafx.graphics/com.sun.glass.ui.View.handleKeyEvent(View.java:547) at javafx.graphics/com.sun.glass.ui.View.notifyKey(View.java:971) at javafx.graphics/com.sun.glass.ui.win.WinApplication._runLoop(Native Method) at javafx.graphics/com.sun.glass.ui.win.WinApplication.lambda$runLoop$3(WinApplication.java:174) at java.base/java.lang.Thread.run(Thread.java:832)

截图：

isCase

还有我的（可能不理想）解决方案：


  /**
   * Makes a new assertion that requires the sum type be a specified term.
   *
   * {{{
   * isCase("Some",Some.unapply,anything)
   * }}}
   */
  def isCase[Sum,Proj](
    termName: String,term: Sum => Option[Proj],assertion: Assertion[Proj]
  )

或者，可以创建一个辅助函数并将其用于此类情况：

sealed trait Result
case object Success extends Result
case class MyFailure(details: String) extends Result

val r: Result = MyFailure("not enought mana")

test("mana") {
  assert(r)(
    isCase[Result,String](
      "details",{ 
        case MyFailure(details) => Some(details) 
        case _                  => None
      },containsString("mana"))
  )
}

现在测试可能看起来像：

  def matches[A](mf: PartialFunction[A,Boolean]): Assertion[A] =
    Assertion.assertion("matches")() {
      a => mf.orElse[A,Boolean]({ case _ => false })(a)
    }
scalascalaunit-testingziozio-test