Added test that tests that correct classes are being created when removing elements

1 files changed, 32 insertions, 0 deletions

diff --git a/test/files/run/t6261.scala b/test/files/run/t6261.scala
new file mode 100644
index 0000000000..873875285d
--- /dev/null
+++ b/test/files/run/t6261.scala
@@ -0,0 +1,32 @@
+import scala.collection.immutable._
+
+object Test extends App {
+
+  def test1() {
+    // test that a HashTrieMap with one leaf element is not created!
+    val x = HashMap.empty + (1->1) + (2->2)
+    if(x.getClass.getSimpleName != "HashTrieMap")
+      println("A hash map containing two non-colliding values should be a HashTrieMap")
+
+    val y = x - 1
+    if(y.getClass.getSimpleName != "HashMap1")
+      println("A hash map containing one element should always use HashMap1")
+  }
+
+  def test2() {
+    // class that always causes hash collisions
+    case class Collision(value:Int) { override def hashCode = 0 }
+
+    // create a set that should have a collison
+    val x = HashMap.empty + (Collision(0)->0) + (Collision(1) ->0)
+    if(x.getClass.getSimpleName != "HashMapCollision1")
+      println("HashMap of size >1 with collisions should use HashMapCollision")
+
+    // remove the collision again by removing all but one element
+    val y = x - Collision(0)
+    if(y.getClass.getSimpleName != "HashMap1")
+      println("HashMap of size 1 should use HashMap1" + y.getClass)
+  }
+  test1()
+  test2()
+}