Test: implement SeqOps with a value class

Author: julienrf

test/junit/scala/collection/ValueClassSeqOpsTest.scala

@@ -0,0 +1,27 @@
+package scala.collection
+
+import org.junit.Test
+
+class ValueClassSeqOpsImpl(private val array: Array[Int]) extends AnyVal with IterableOnce[Int] with SeqOps[Int, Seq, ValueClassSeqOpsImpl] {
+  def apply(i: Int): Int = array(i)
+  def length: Int = array.length
+  def iterator: Iterator[Int] = array.iterator
+  def toIterable: Iterable[Int] = array.toIndexedSeq
+  protected def coll: ValueClassSeqOpsImpl = this
+  protected def fromSpecific(coll: IterableOnce[Int]): ValueClassSeqOpsImpl =
+    new ValueClassSeqOpsImpl(coll.iterator.toArray)
+  def iterableFactory: IterableFactory[Seq] = Seq
+  protected def newSpecificBuilder: mutable.Builder[Int, ValueClassSeqOpsImpl] =
+    Array.newBuilder[Int].mapResult(new ValueClassSeqOpsImpl(_))
+  override def toString = mkString("ValueClassSeqOpsImpl(", ", ", ")")
+}
+
+class ValueClassSeqOpsTest {
+  @Test
+  def testPermutation(): Unit = {
+    val array = Array(1, 2, 3)
+    val wrapper = new ValueClassSeqOpsImpl(array)
+    val permutations = wrapper.permutations.toSeq.map(_.toSeq)
+    assert(permutations == List(1, 2, 3).permutations.toSeq)
+  }
+}