diff --git a/core/tests/Drupal/Tests/Core/Ajax/AjaxCommandsTest.php b/core/tests/Drupal/Tests/Core/Ajax/AjaxCommandsTest.php
index 1872406..1dd66b8 100644
--- a/core/tests/Drupal/Tests/Core/Ajax/AjaxCommandsTest.php
+++ b/core/tests/Drupal/Tests/Core/Ajax/AjaxCommandsTest.php
@@ -294,27 +294,16 @@ public function testSettingsCommand() {
    * @covers \Drupal\Core\Ajax\OpenDialogCommand
    */
   public function testOpenDialogCommand() {
-    $command = $this->getMockBuilder('Drupal\Core\Ajax\OpenDialogCommand')
-      ->setConstructorArgs([
-        '#some-dialog', 'Title', '<p>Text!</p>', [
-          'url' => FALSE,
-          'width' => 500,
-        ],
-      ])
-      ->setMethods(['getRenderedContent'])
-      ->getMock();
-
-    // This method calls the render service, which isn't available. We want it
-    // to do nothing so we mock it to return a known value.
-    $command->expects($this->once())
-      ->method('getRenderedContent')
-      ->willReturn('rendered content');
+    $command = new OpenDialogCommand('#some-dialog', 'Title', '<p>Text!</p>', [
+      'url' => FALSE,
+      'width' => 500,
+    ]);
 
     $expected = [
       'command' => 'openDialog',
       'selector' => '#some-dialog',
       'settings' => NULL,
-      'data' => 'rendered content',
+      'data' => '<p>Text!</p>',
       'dialogOptions' => [
         'url' => FALSE,
         'width' => 500,
@@ -323,47 +312,10 @@ public function testOpenDialogCommand() {
       ],
     ];
     $this->assertEquals($expected, $command->render());
-  }
-
-  /**
-   * Tests that OpenDialogCommand objects title can be changed.
-   */
-  public function testOpenDialogCommandSetTitle() {
-    $command = $this
-      ->getMockBuilder(OpenDialogCommand::class)
-      ->setConstructorArgs([
-        '#some-dialog',
-        'Dialog title',
-        '<p>Text!</p>',
-        [
-          'url' => FALSE,
-          'width' => 500,
-        ],
-      ])
-      ->setMethods(['getRenderedContent'])
-      ->getMock();
-
-    $command
-      ->expects(static::once())
-      ->method('getRenderedContent')
-      ->willReturn('<p>Text!</p>');
-
-    $expected = [
-      'command' => 'openDialog',
-      'selector' => '#some-dialog',
-      'settings' => NULL,
-      'data' => '<p>Text!</p>',
-      'dialogOptions' => [
-        'url' => FALSE,
-        'width' => 500,
-        'title' => 'New title',
-        'modal' => FALSE,
-      ],
-    ];
 
     $command->setDialogTitle('New title');
-
-    $this->assertEquals($command->render(), $expected, "OpenDialogCommand::render() didn't return the expected array.");
+    $expected['dialogOptions']['title'] = 'New title';
+    $this->assertEquals($expected, $command->render());
   }
 
   /**