scala 比较集合内容与 ScalaTest
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Comparing collection contents with ScalaTest
提问by Michael Koval
I'm trying to unit-test some Scala that is very collection-heavy. These collections are returned as Iterable[T], so I am interested in the contentsof the collection, even if the underlying types differ. This is actually two related problems:
我正在尝试对一些非常需要大量收集的 Scala 进行单元测试。这些集合作为 返回Iterable[T]，因此我对集合的内容感兴趣，即使基础类型不同。这实际上是两个相关的问题：
- How do I assert that two orderedcollections contain the same sequence of elements?
- How do I assert that two unorderedcollections contain the same set of elements?
- 如何断言两个有序集合包含相同的元素序列？
- 如何断言两个无序集合包含相同的元素集？
In summary, I'm looking the Scala-equivalent of NUnit's CollectionAssert.AreEqual(ordered) and CollectionAssert.AreEquivalent(unordered) in ScalaTest:
总之，我正在ScalaTest 中寻找 NUnit 的CollectionAssert.AreEqual（有序）和CollectionAssert.AreEquivalent（无序）的 Scala 等价物：
Set(1, 2) should equal (List(1, 2)) // ordered, pass
Iterable(2, 1) should equal (Iterable(1, 2)) // unordered, pass
采纳答案by Luigi Plinge
You could try .toSeqfor ordered collections and .toSetfor unordered, which captures what you want as far as I understand it.
您可以尝试.toSeq有序集合和.toSet无序集合，据我所知，它们可以捕获您想要的内容。
The following passes:
以下通过：
class Temp extends FunSuite with ShouldMatchers {
test("1") { Array(1, 2).toSeq should equal (List(1, 2).toSeq) }
test("2") { Array(2, 1).toSeq should not equal (List(1, 2).toSeq) }
test("2b") { Array(2, 1) should not equal (List(1, 2)) }
test("3") { Iterable(2, 1).toSet should equal (Iterable(1, 2).toSet) }
test("4") { Iterable(2, 1) should not equal (Iterable(1, 2)) }
}
BTW a Setis not ordered.
顺便说一句Set，没有订购。
edit:To avoid removing duplicate elements, try toSeq.sorted. The following pass:
编辑：为避免删除重复元素，请尝试toSeq.sorted. 以下通过：
test("5") { Iterable(2, 1).toSeq.sorted should equal (Iterable(1, 2).toSeq.sorted) }
test("6") { Iterable(2, 1).toSeq should not equal (Iterable(1, 2).toSeq) }
edit 2:For unordered collections where elements cannot be sorted, you can use this method:
编辑2：对于元素无法排序的无序集合，您可以使用此方法：
def sameAs[A](c: Traversable[A], d: Traversable[A]): Boolean =
if (c.isEmpty) d.isEmpty
else {
val (e, f) = d span (c.head !=)
if (f.isEmpty) false else sameAs(c.tail, e ++ f.tail)
}
e.g. (note use of symbols 'a 'b 'cwhich have no defined ordering)
例如（注意使用'a 'b 'c没有定义顺序的符号）
test("7") { assert( sameAs(Iterable(2, 1), Iterable(1, 2) )) }
test("8") { assert( sameAs(Array('a, 'c, 'b), List('c, 'a, 'b) )) }
test("9") { assert( sameAs("cba", Set('a', 'b', 'c') )) }
Alternative sameAsimplementation:
替代sameAs实现：
def sameAs[A](c: Traversable[A], d: Traversable[A]) = {
def counts(e: Traversable[A]) = e groupBy identity mapValues (_.size)
counts(c) == counts(d)
}
回答by Christoph Dittberner
Meanwhile you can use
同时你可以使用
Iterable(2, 1) should contain theSameElementsAs Iterable(1, 2)
To test the ordered set you have to convert it to a sequence.
要测试有序集，您必须将其转换为序列。
Set(1, 2).toSeq should contain theSameElementsInOrderAs List(1, 2)
