diff --git a/core/modules/menu_link/lib/Drupal/menu_link/MenuTree.php b/core/modules/menu_link/lib/Drupal/menu_link/MenuTree.php
index a4d5d7e..3362b42 100644
--- a/core/modules/menu_link/lib/Drupal/menu_link/MenuTree.php
+++ b/core/modules/menu_link/lib/Drupal/menu_link/MenuTree.php
@@ -596,6 +596,9 @@ public function buildTreeData(array $links, array $parents = array(), $depth = 1
     return $data['tree'];
   }
 
+  /**
+   * Prepares the data for calling $this->treeDataRecursive().
+   */
   protected function doBuildTreeData(array $links, array $parents = array(), $depth = 1) {
     // Reverse the array so we can use the more efficient array_pop() function.
     $links = array_reverse($links);
diff --git a/core/modules/menu_link/tests/Drupal/menu_link/Tests/MenuTreeTest.php b/core/modules/menu_link/tests/Drupal/menu_link/Tests/MenuTreeTest.php
index 162dead..5d69c20 100644
--- a/core/modules/menu_link/tests/Drupal/menu_link/Tests/MenuTreeTest.php
+++ b/core/modules/menu_link/tests/Drupal/menu_link/Tests/MenuTreeTest.php
@@ -155,19 +155,27 @@ public function testBuildTreeDataWithSingleLevel() {
     $items[] = array(
       'mlid' => 1,
       'depth' => 1,
+      'weight' => 0,
+      'title' => '',
       'route_name' => 'example1',
+      'access' => TRUE,
     );
     $items[] = array(
       'mlid' => 2,
       'depth' => 1,
+      'weight' => 0,
+      'title' => '',
       'route_name' => 'example2',
+      'access' => TRUE,
     );
 
     $result = $this->menuTree->buildTreeData($items, array(), 1);
 
     $this->assertCount(2, $result);
-    $this->assertEquals(array('mlid' => 1, 'depth' => 1, 'route_name' => 'example1', 'in_active_trail' => FALSE), $result[1]['link']);
-    $this->assertEquals(array('mlid' => 2, 'depth' => 1, 'route_name' => 'example2', 'in_active_trail' => FALSE), $result[2]['link']);
+    $result1 = array_shift($result);
+    $this->assertEquals($items[0] + array('in_active_trail' => FALSE), $result1['link']);
+    $result2 = array_shift($result);
+    $this->assertEquals($items[1] + array('in_active_trail' => FALSE), $result2['link']);
   }
 
   /**
@@ -181,19 +189,27 @@ public function testBuildTreeDataWithSingleLevelAndActiveItem() {
     $items[] = array(
       'mlid' => 1,
       'depth' => 1,
+      'weight' => 0,
+      'title' => '',
       'route_name' => 'example1',
+      'access' => TRUE,
     );
     $items[] = array(
       'mlid' => 2,
       'depth' => 1,
+      'weight' => 0,
+      'title' => '',
       'route_name' => 'example2',
+      'access' => TRUE,
     );
 
     $result = $this->menuTree->buildTreeData($items, array(1), 1);
 
     $this->assertCount(2, $result);
-    $this->assertEquals(array('mlid' => 1, 'depth' => 1, 'route_name' => 'example1', 'in_active_trail' => TRUE), $result[1]['link']);
-    $this->assertEquals(array('mlid' => 2, 'depth' => 1, 'route_name' => 'example2', 'in_active_trail' => FALSE), $result[2]['link']);
+    $result1 = array_shift($result);
+    $this->assertEquals($items[0] + array('in_active_trail' => TRUE), $result1['link']);
+    $result2 = array_shift($result);
+    $this->assertEquals($items[1] + array('in_active_trail' => FALSE), $result2['link']);
   }
 
   /**
@@ -207,45 +223,27 @@ public function testBuildTreeDataWithSingleLevelAndNoActiveItem() {
     $items[] = array(
       'mlid' => 1,
       'depth' => 1,
+      'weight' => 0,
+      'title' => '',
       'route_name' => 'example1',
+      'access' => TRUE,
     );
     $items[] = array(
       'mlid' => 2,
       'depth' => 1,
+      'weight' => 0,
+      'title' => '',
       'route_name' => 'example2',
+      'access' => TRUE,
     );
 
     $result = $this->menuTree->buildTreeData($items, array(3), 1);
 
     $this->assertCount(2, $result);
-    $this->assertEquals(array('mlid' => 1, 'depth' => 1, 'route_name' => 'example1', 'in_active_trail' => FALSE), $result[1]['link']);
-    $this->assertEquals(array('mlid' => 2, 'depth' => 1, 'route_name' => 'example2', 'in_active_trail' => FALSE), $result[2]['link']);
-  }
-
-  /**
-   * Tests buildTreeData with multiple levels.
-   *
-   * @covers ::buildTreeData
-   * @covers ::doBuildTreeData
-   */
-  public function testBuildTreeDataWithMultipleLevels() {
-    $items = array();
-    $items[] = array(
-      'mlid' => 1,
-      'depth' => 1,
-      'route_name' => 'example1',
-    );
-    $items[] = array(
-      'mlid' => 2,
-      'depth' => 1,
-      'route_name' => 'example2',
-    );
-
-    $result = $this->menuTree->buildTreeData($items, array(3), 1);
-
-    $this->assertCount(2, $result);
-    $this->assertEquals(array('mlid' => 1, 'depth' => 1, 'route_name' => 'example1', 'in_active_trail' => FALSE), $result[1]['link']);
-    $this->assertEquals(array('mlid' => 2, 'depth' => 1, 'route_name' => 'example2', 'in_active_trail' => FALSE), $result[2]['link']);
+    $result1 = array_shift($result);
+    $this->assertEquals($items[0] + array('in_active_trail' => FALSE), $result1['link']);
+    $result2 = array_shift($result);
+    $this->assertEquals($items[1] + array('in_active_trail' => FALSE), $result2['link']);
   }
 
   /**
@@ -256,22 +254,22 @@ public function testBuildTreeDataWithMultipleLevels() {
    */
   public function testBuildTreeWithComplexData() {
     $items = array(
-      1 => array('mlid' => 1, 'depth' => 1),
-      2 => array('mlid' => 2, 'depth' => 1),
-      3 => array('mlid' => 3, 'depth' => 2),
-      4 => array('mlid' => 4, 'depth' => 3),
-      5 => array('mlid' => 5, 'depth' => 1),
+      1 => array('mlid' => 1, 'depth' => 1, 'route_name' => 'example1', 'access' => TRUE, 'weight' => 0, 'title' => ''),
+      2 => array('mlid' => 2, 'depth' => 1, 'route_name' => 'example2', 'access' => TRUE, 'weight' => 0, 'title' => ''),
+      3 => array('mlid' => 3, 'depth' => 2, 'route_name' => 'example3', 'access' => TRUE, 'weight' => 0, 'title' => ''),
+      4 => array('mlid' => 4, 'depth' => 3, 'route_name' => 'example4', 'access' => TRUE, 'weight' => 0, 'title' => ''),
+      5 => array('mlid' => 5, 'depth' => 1, 'route_name' => 'example5', 'access' => TRUE, 'weight' => 0, 'title' => ''),
     );
 
     $tree = $this->menuTree->buildTreeData($items);
 
     // Validate that parent items #1, #2, and #5 exist on the root level.
-    $this->assertEquals($items[1]['mlid'], $tree[1]['link']['mlid']);
-    $this->assertEquals($items[2]['mlid'], $tree[2]['link']['mlid']);
-    $this->assertEquals($items[5]['mlid'], $tree[5]['link']['mlid']);
+    $this->assertEquals($items[1]['mlid'], $tree['50000  1']['link']['mlid']);
+    $this->assertEquals($items[2]['mlid'], $tree['50000  2']['link']['mlid']);
+    $this->assertEquals($items[5]['mlid'], $tree['50000  5']['link']['mlid']);
 
     // Validate that child item #4 exists at the correct location in the hierarchy.
-    $this->assertEquals($items[4]['mlid'], $tree[2]['below'][3]['below'][4]['link']['mlid']);
+    $this->assertEquals($items[4]['mlid'], $tree['50000  2']['below']['50000  3']['below']['50000  4']['link']['mlid']);
   }
 
   /**
@@ -354,7 +352,6 @@ public function testCheckAccessWithSingleLevel() {
 
     // Build the menu tree and check access for all of the items.
     $tree = $this->menuTree->buildTreeData($items);
-    $this->menuTree->checkAccess($tree);
 
     $this->assertCount(1, $tree);
     $item = reset($tree);