问

scalac在ScalaTest测试中找到了错误的所有方法

手机用户2502898521 发布于 2023-02-12 19:28

scala

我有延伸的ScalaTest 2类GeneratorDrivenPropertyChecks,也间接地延伸FeatureSpec和Matchers(经由性状我写延伸这两个类).它有这样的代码:

forAll(mySequence) { myItem =>
  myItem.applicationID should be (foo.applicationID)
}

这无法编译,因为scalac说:

[error] APISpec.scala:253: value applicationID is not a member of Seq[com.company.Item]
[error]          myItem.applicationID should be (foo.applicationID)
[error]                 ^

事实证明,至少根据Eclipse Scala IDE,编译器正在解析"forAll",意思是这个方法,在GeneratorDrivenpropertyChecks:

  /**
   * Performs a property check by applying the specified property check function to arguments
   * supplied by the specified generators.
   *
   * 
   * Here's an example:
   * 
   *
   *    * import org.scalacheck.Gen
   *
   * // Define your own string generator:
   * val famousLastWords = for {
   *   s <- Gen.oneOf("the", "program", "compiles", "therefore", "it", "should", "work")
   * } yield s
   * 
   * forAll (famousLastWords) { (a: String) =>
   *   a.length should equal ((a).length)
   * }
   * 
   *
   * @param fun the property check function to apply to the generated arguments
   */
  def forAll[A](genA: Gen[A], configParams: PropertyCheckConfigParam*)(fun: (A) => Unit)
    (implicit
      config: PropertyCheckConfig,
      shrA: Shrink[A]
    ) {
      // body omitted
  }

这不是forAll我想在这里使用的方法!

这是ScalaTest中的错误(即两个方法都不应该被命名forAll)？

我应该如何调用正确的方法？

1 个回答

这是ScalaTest中的错误吗？

它演示了方法重载的局限性.

在一篇关于无私特质的文章中,Bill Venners将这种模式描述为这些命名冲突的解决方法.

~~在您的情况下,首选一个重载,因为它在"派生类"中定义.~~

(我认为;我不是这些测试框架的用户,其中一个源是生成的,所以测试这不是一个简单的问题,即启动sbt并查看代码.)

(编辑:scaladoc说你应该这样做import Inspectors._.也许你希望继承它.Matchers因为它也建议导入它的伴侣,虽然这对我来说不合适.如果你这样做import Inspectors._,你实际上不能通过导入名称.)

(编辑:解释命名位:请参阅规范的第2章的开头,其中它表示名称的绑定具有优先级,并且您继承的名称优先于您导入的名称.)

无论如何,一种解决方案是重新混入Inspectors,如下所示.

另一种解决方案是使用重命名导入方法:

import Inspectors.{ forAll => iforAll }

尝试选项"-Xprint:typer"," - Xlog-implicit-conversions"来查看正在发生的事情是很有用的.在您的情况下,您的集合通过Gen.valueScalaCheck 1.10中的隐式视图提升为"常量gen" .

import org.scalatest._
import org.scalatest.prop._

//class MySpec extends FeatureSpec with Matchers with GeneratorDrivenPropertyChecks

class MySpec extends FeatureSpec with Matchers with GeneratorDrivenPropertyChecks with Inspectors {
  case class Foo(id: Int)
  val items = 1 to 10 map (Foo.apply(_))
  forAll(items) { x => Console println x.id } 
}

object Test extends App {
  case class Foo(id: Int)
  val items = 1 to 10 map (Foo.apply(_))
  val sut = new MySpec
  sut.forAll(items) { x => Console println x.id }
  //sut.forAll[Foo](items) { x => Console println x.i }
}

一些调试输出:

/*

[info] /home/apm/projects/skala-unit-tests/src/test/scala/maqi/MySpec.scala:15: inferred view from scala.collection.immutable.IndexedSeq[maqi.Test.Foo] to org.scalacheck.Gen[?] = scalacheck.this.Gen.value[scala.collection.immutable.IndexedSeq[maqi.Test.Foo]]:(x: scala.collection.immutable.IndexedSeq[maqi.Test.Foo])org.scalacheck.Gen[scala.collection.immutable.IndexedSeq[maqi.Test.Foo]]


> test
[info] Compiling 3 Scala sources to /home/apm/projects/skala-unit-tests/target/scala-2.10/test-classes...
[error] /home/apm/projects/skala-unit-tests/src/test/scala/maqi/MySpec.scala:16: overloaded method value forAll with alternatives:
[error]   (genAndNameA: (org.scalacheck.Gen[maqi.Test.Foo], String),configParams: maqi.Test.sut.PropertyCheckConfigParam*)(fun: maqi.Test.Foo => Unit)(implicit config: maqi.Test.sut.PropertyCheckConfig, implicit shrA: org.scalacheck.Shrink[maqi.Test.Foo])Unit <and>
[error]   (genA: org.scalacheck.Gen[maqi.Test.Foo],configParams: maqi.Test.sut.PropertyCheckConfigParam*)(fun: maqi.Test.Foo => Unit)(implicit config: maqi.Test.sut.PropertyCheckConfig, implicit shrA: org.scalacheck.Shrink[maqi.Test.Foo])Unit <and>
[error]   (nameA: String,configParams: maqi.Test.sut.PropertyCheckConfigParam*)(fun: maqi.Test.Foo => Unit)(implicit config: maqi.Test.sut.PropertyCheckConfig, implicit arbA: org.scalacheck.Arbitrary[maqi.Test.Foo], implicit shrA: org.scalacheck.Shrink[maqi.Test.Foo])Unit <and>
[error]   (fun: maqi.Test.Foo => Unit)(implicit config: maqi.Test.sut.PropertyCheckConfig, implicit arbA: org.scalacheck.Arbitrary[maqi.Test.Foo], implicit shrA: org.scalacheck.Shrink[maqi.Test.Foo])Unit
[error]  cannot be applied to (scala.collection.immutable.IndexedSeq[maqi.Test.Foo])
[error]   sut.forAll[Foo](items) { x => Console println x.i }
[error]             ^
*/

2023-02-12 19:31 回答

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