用ScalaCheck测试java类

Question

我正在尝试用scalacheck测试一个java类。例如，我在...\src\main\java\中有一个类队列

public class Queue<Item> {

private Node first;
private Node last;
private int N;

private class Node {
    Item item;
    Node next;
}

public boolean isEmpty () { return first == null; }
public int size() { return N;}

public void enqueue(Item item) {
    Node oldLast = last;
    last = new Node();
    last.item = item;
    last.next = null;
    if(isEmpty()) 
        first = last;
    else 
        oldLast = last;
    N++;
}

public Item dequeue() {
    Item item = first.item;
    first = first.next;
    if(isEmpty()) 
        last = null;
    N--;
    return item;
}

}

然后，我在...\src\test\scala\中有一个scala测试类...\src\test\scala\。

import org.scalacheck.Gen.{choose, oneOf}
import org.scalacheck.Prop.forAll
import org.scalacheck.Gen.choose
import org.scalacheck._
import org.scalacheck.Prop._

class QueueTest extends Properties("Queue") {

    Queue<Int> q;

    property("enque") = Prop.forAll { (n: Int) =>
        (q.enque(n) == n)
    }
}

我只需要一个关于如何扩展java泛型队列类的先导？我所要做的就是测试enqueue和dequeue方法。

我看过Rick的github的StringUtils.scala示例，但它仍然不清楚。

如有任何建议，将不胜感激

Answer 1

对enque的唯一可能测试是调用它并确保不引发异常。

如果这是我的分配，我将为所有List[Int]定义一个属性，并测试该任意列表中的项的排队和退出队列，这样队列返回的项与列表的顺序完全相同。

根据要求，以下是一些例子：

import org.scalacheck.Properties
import org.scalacheck.Prop.forAll

object QueueSpec extends Properties("Queue") {

  property("enqueue never throws an exception") = forAll {(xs: List[Int]) =>
    val q = new Queue[Int]
    xs.foreach(q.enqueue)
    true
  }

  property("dequeue always presents elements in FIFO order") = forAll {(xs: List[Int]) =>
    val q = new Queue[Int]
    xs.foreach(q.enqueue)
    xs.forall{_ == q.dequeue}
  }

  property("isEmpty always true after complete dequeue") = forAll {(xs: List[Int]) =>
    val q = new Queue[Int]
    xs.foreach(q.enqueue)
    xs.foreach(_ => q.dequeue)
    q.isEmpty
  }
}

build.sbt：

scalaVersion := "2.11.2"

libraryDependencies ++= Seq(
  "org.scalacheck" %% "scalacheck" % "1.11.5" % "test"
)

结果：

$ sbt test
[info] + Queue.enqueue never throws an exception: OK, passed 100 tests.
[info] + Queue.dequeue always presents elements in FIFO order: OK, passed 100 tests.
[info] + Queue.isEmpty always true after complete dequeue: OK, passed 100 tests.
[info] Passed: Total 3, Failed 0, Errors 0, Passed 3
[success] Total time: 2 s, completed 24/09/2014 9:28:10 PM