Split tests for MutableList.shuffle and Iterable.shuffled

libraries/stdlib/test/collections/CollectionTest.kt

@@ -1123,6 +1123,32 @@ class CollectionTest {
         }
     }
 
+    @Test fun shuffled() {
+        val data = List(100) { it }
+        val list = data.toMutableList()
+        val shuffled = list.shuffled()
+
+        assertEquals(data, list)
+        assertNotEquals(list, shuffled)
+        assertEquals(list.toSet(), shuffled.toSet())
+        assertEquals(list.size, shuffled.distinct().size)
+    }
+
+    @Test fun shuffledPredictably() {
+        val data = List(10) { it }
+        val list = data.toMutableList()
+        val shuffled1 = list.shuffled(Random(1))
+        val shuffled11 = list.shuffled(Random(1))
+
+        assertEquals(data, list)
+
+        assertEquals(shuffled1, shuffled11)
+        assertEquals("[1, 4, 0, 6, 2, 8, 9, 7, 3, 5]", shuffled1.toString())
+
+        val shuffled2 = list.shuffled(Random(42))
+        assertEquals("[5, 0, 4, 9, 2, 8, 1, 7, 6, 3]", shuffled2.toString())
+    }
+
     @Test fun decomposeFirst() {
         val (first) = listOf(1, 2)
         assertEquals(first, 1)

libraries/stdlib/test/collections/MutableCollectionsTest.kt

@@ -161,25 +161,29 @@ class MutableCollectionTest {
         }
     }
 
-    @Test fun shuffled() {
+    @Test fun shuffle() {
-        val list = MutableList(100) { it }
+        val list = List(100) { it }
-        val shuffled = list.shuffled()
+        forAllStandardMutableLists(list) { shuffled ->
-
+            shuffled.shuffle()
-        assertNotEquals(list, shuffled)
+            assertNotEquals(list, shuffled)
-        assertEquals(list.toSet(), shuffled.toSet())
+            assertEquals(list.toSet(), shuffled.toSet())
-        assertEquals(list.size, shuffled.distinct().size)
+            assertEquals(list.size, shuffled.distinct().size)
+        }
     }
 
-    @Test fun shuffledPredictably() {
+    @Test fun shufflePredictably() {
         val list = List(10) { it }
-        val shuffled1 = list.shuffled(Random(1))
+        repeat(2) {
-        val shuffled11 = list.shuffled(Random(1))
+            forAllStandardMutableLists(list) { shuffled1 ->
+                shuffled1.shuffle(Random(1))
+                assertEquals("[1, 4, 0, 6, 2, 8, 9, 7, 3, 5]", shuffled1.toString())
+            }
+        }
 
-        assertEquals(shuffled1, shuffled11)
+        forAllStandardMutableLists(list) { shuffled2 ->
-        assertEquals("[1, 4, 0, 6, 2, 8, 9, 7, 3, 5]", shuffled1.toString())
+            shuffled2.shuffle(Random(42))
-
+            assertEquals("[5, 0, 4, 9, 2, 8, 1, 7, 6, 3]", shuffled2.toString())
-        val shuffled2 = list.shuffled(Random(42))
+        }
-        assertEquals("[5, 0, 4, 9, 2, 8, 1, 7, 6, 3]", shuffled2.toString())
     }
 
 }