Assert array keys replaced by shuffle()

tests/TestCase/Collection/CollectionTest.php

@@ -934,6 +934,7 @@ class CollectionTest extends TestCase
         $collection = (new Collection(['a' => 1]))->append(['a' => 2])->shuffle();
         $result = $collection->toArray();
         $this->assertCount(2, $result);
+        $this->assertEquals([0, 1], array_keys($result));
         $this->assertContainsEquals(1, $result);
         $this->assertContainsEquals(2, $result);
     }