diff --git a/core/modules/file/lib/Drupal/file/Tests/FileListingTest.php b/core/modules/file/lib/Drupal/file/Tests/FileListingTest.php
index 2b2bc55..1848edf 100644
--- a/core/modules/file/lib/Drupal/file/Tests/FileListingTest.php
+++ b/core/modules/file/lib/Drupal/file/Tests/FileListingTest.php
@@ -75,14 +75,14 @@ function testFileListingPages() {
     }
 
     foreach ($nodes as &$node) {
-      $this->drupalGet('node/' . $node->nid . '/edit');
+      $this->drupalGet('node/' . $node->id() . '/edit');
       $file = $this->getTestFile('image');
 
       $edit = array(
         'files[file_' . Language::LANGCODE_NOT_SPECIFIED . '_' . 0 . ']' => drupal_realpath($file->getFileUri()),
       );
       $this->drupalPost(NULL, $edit, t('Save'));
-      $node = entity_load('node', $node->nid)->getNGEntity();
+      $node = entity_load('node', $node->id());
     }
 
     $this->drupalGet('admin/content/files');
diff --git a/core/modules/node/lib/Drupal/node/Tests/NodeAccessLanguageTest.php b/core/modules/node/lib/Drupal/node/Tests/NodeAccessLanguageTest.php
index 21ece4c..6facbdb 100644
--- a/core/modules/node/lib/Drupal/node/Tests/NodeAccessLanguageTest.php
+++ b/core/modules/node/lib/Drupal/node/Tests/NodeAccessLanguageTest.php
@@ -65,7 +65,7 @@ function testNodeAccess() {
     // Creating a public node with langcode Hungarian, will be saved as the
     // fallback in node access table.
     $node_public = $this->drupalCreateNode(array('body' => array(array()), 'langcode' => 'hu', 'private' => FALSE));
-    $this->assertTrue($node_public->langcode == 'hu', 'Node created as Hungarian.');
+    $this->assertTrue($node_public->language()->id == 'hu', 'Node created as Hungarian.');
 
     // Tests the default access is provided for the public Hungarian node.
     $this->assertNodeAccess($expected_node_access, $node_public, $web_user);
@@ -82,7 +82,7 @@ function testNodeAccess() {
     // Creating a public node with no special langcode, like when no language
     // module enabled.
     $node_public_no_language = $this->drupalCreateNode(array('private' => FALSE));
-    $this->assertTrue($node_public_no_language->langcode == Language::LANGCODE_NOT_SPECIFIED, 'Node created with not specified language.');
+    $this->assertTrue($node_public_no_language->language()->id == Language::LANGCODE_NOT_SPECIFIED, 'Node created with not specified language.');
 
     // Tests that access is granted if requested with no language.
     $this->assertNodeAccess($expected_node_access, $node_public_no_language, $web_user);
@@ -124,7 +124,7 @@ function testNodeAccessPrivate() {
     // Creating a private node with langcode Hungarian, will be saved as the
     // fallback in node access table.
     $node_public = $this->drupalCreateNode(array('body' => array(array()), 'langcode' => 'hu', 'private' => TRUE));
-    $this->assertTrue($node_public->langcode == 'hu', 'Node created as Hungarian.');
+    $this->assertTrue($node_public->language()->id == 'hu', 'Node created as Hungarian.');
 
     // Tests the default access is not provided for the private Hungarian node.
     $this->assertNodeAccess($expected_node_access_no_access, $node_public, $web_user);
@@ -141,7 +141,7 @@ function testNodeAccessPrivate() {
     // Creating a private node with no special langcode, like when no language
     // module enabled.
     $node_private_no_language = $this->drupalCreateNode(array('private' => TRUE));
-    $this->assertTrue($node_private_no_language->langcode == Language::LANGCODE_NOT_SPECIFIED, 'Node created with not specified language.');
+    $this->assertTrue($node_private_no_language->language()->id == Language::LANGCODE_NOT_SPECIFIED, 'Node created with not specified language.');
 
     // Tests that access is not granted if requested with no language.
     $this->assertNodeAccess($expected_node_access_no_access, $node_private_no_language, $web_user);
@@ -183,17 +183,17 @@ function testNodeAccessQueryTag() {
     // Creating a private node with langcode Hungarian, will be saved as
     // the fallback in node access table.
     $node_private = $this->drupalCreateNode(array('body' => array(array()), 'langcode' => 'hu', 'private' => TRUE));
-    $this->assertTrue($node_private->langcode == 'hu', 'Node created as Hungarian.');
+    $this->assertTrue($node_private->language()->id == 'hu', 'Node created as Hungarian.');
 
     // Creating a public node with langcode Hungarian, will be saved as
     // the fallback in node access table.
     $node_public = $this->drupalCreateNode(array('body' => array(array()), 'langcode' => 'hu', 'private' => FALSE));
-    $this->assertTrue($node_public->langcode == 'hu', 'Node created as Hungarian.');
+    $this->assertTrue($node_public->language()->id == 'hu', 'Node created as Hungarian.');
 
     // Creating a public node with no special langcode, like when no language
     // module enabled.
     $node_no_language = $this->drupalCreateNode(array('private' => FALSE));
-    $this->assertTrue($node_no_language->langcode == Language::LANGCODE_NOT_SPECIFIED, 'Node created with not specified language.');
+    $this->assertTrue($node_no_language->language()->id == Language::LANGCODE_NOT_SPECIFIED, 'Node created with not specified language.');
 
     // Query the nodes table as the web user with the node access tag and no
     // specific langcode.
diff --git a/core/modules/system/lib/Drupal/system/Tests/ParamConverter/UpcastingTest.php b/core/modules/system/lib/Drupal/system/Tests/ParamConverter/UpcastingTest.php
index fb7aae7..f9556a9 100644
--- a/core/modules/system/lib/Drupal/system/Tests/ParamConverter/UpcastingTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/ParamConverter/UpcastingTest.php
@@ -51,12 +51,12 @@ public function testUpcasting() {
 
     // paramconverter_test/test_node_user_user/{node}/{foo}/{user}
     // options.parameters.foo.type = entity:user
-    $this->drupalGet("paramconverter_test/test_node_user_user/{$node->nid}/" . $user->id() . "/" . $user->id());
+    $this->drupalGet("paramconverter_test/test_node_user_user/" . $node->id() . "/" . $user->id() . "/" . $user->id());
     $this->assertRaw("user: {$user->label()}, node: {$node->label()}, foo: {$user->label()}", 'foo converted to user as well');
 
     // paramconverter_test/test_node_node_foo/{user}/{node}/{foo}
     // options.parameters.user.type = entity:node
-    $this->drupalGet("paramconverter_test/test_node_node_foo/{$node->nid}/{$node->nid}/$foo");
+    $this->drupalGet("paramconverter_test/test_node_node_foo/" . $node->id() . "/" . $node->id() . "/$foo");
     $this->assertRaw("user: {$node->label()}, node: {$node->label()}, foo: $foo", 'user is upcast to node (rather than to user)');
   }