diff --git a/panelizer.post_update.php b/panelizer.post_update.php
index 4149ff0..fcb8e18 100644
--- a/panelizer.post_update.php
+++ b/panelizer.post_update.php
@@ -27,7 +27,7 @@ function panelizer_post_update_rename_layout_machine_names(&$sandbox) {
   $results = [];
   // Update overridden panelizer entities.
   foreach ($panelizer_manager->getDefinitions() as $entity_type => $definition) {
-    if (db_table_exists($entity_type . '__panelizer')) {
+    if (\Drupal::database()->schema()->tableExists($entity_type . '__panelizer')) {
       $storage = \Drupal::entityTypeManager()->getStorage($entity_type);
       $ids = $storage->getQuery()
         ->condition('panelizer', serialize([]), '<>')
diff --git a/panelizer_quickedit/tests/src/FunctionalJavascript/PanelizerQuickEditTest.php b/panelizer_quickedit/tests/src/FunctionalJavascript/PanelizerQuickEditTest.php
index 005668a..8bddec5 100644
--- a/panelizer_quickedit/tests/src/FunctionalJavascript/PanelizerQuickEditTest.php
+++ b/panelizer_quickedit/tests/src/FunctionalJavascript/PanelizerQuickEditTest.php
@@ -4,14 +4,14 @@ namespace Drupal\Tests\panelizer_quickedit\FunctionalJavascript;
 
 use Drupal\field\Entity\FieldConfig;
 use Drupal\field\Entity\FieldStorageConfig;
-use Drupal\FunctionalJavascriptTests\JavascriptTestBase;
+use Drupal\FunctionalJavascriptTests\WebDriverTestBase;
 
 /**
  * Tests that a Panelized Node can be Quick-Edited.
  *
  * @group panelizer
  */
-class PanelizerQuickEditTest extends JavascriptTestBase {
+class PanelizerQuickEditTest extends WebDriverTestBase {
 
   /**
    * {@inheritdoc}
@@ -69,12 +69,12 @@ class PanelizerQuickEditTest extends JavascriptTestBase {
 
     // Enable Panelizer for Articles.
     $this->drupalGet('admin/structure/types/manage/page/display');
-    $this->assertResponse(200);
+    $this->assertSession()->statusCodeEquals(200);
     $edit = [
       'panelizer[enable]' => TRUE,
     ];
     $this->drupalPostForm(NULL, $edit, t('Save'));
-    $this->assertResponse(200);
+    $this->assertSession()->statusCodeEquals(200);
   }
 
   /**
@@ -107,7 +107,7 @@ class PanelizerQuickEditTest extends JavascriptTestBase {
 
     // Visit the new node.
     $this->drupalGet('node/' . $node->id());
-    $this->assertResponse(200);
+    $this->assertSession()->statusCodeEquals(200);
 
     // This is the unique ID we append to normal Quick Edit field IDs.
     $panelizer_id = 'panelizer-full-block-id-' . $block_id;
@@ -138,7 +138,7 @@ class PanelizerQuickEditTest extends JavascriptTestBase {
 
     // Re-visit the node to make sure the edit worked.
     $this->drupalGet('node/' . $node->id());
-    $this->assertResponse(200);
+    $this->assertSession()->statusCodeEquals(200);
     $this->assertSession()->pageTextContains('Hello world');
   }
 
diff --git a/src/Form/PanelizerWizardContextDeleteForm.php b/src/Form/PanelizerWizardContextDeleteForm.php
index e4175e0..29e9bf3 100644
--- a/src/Form/PanelizerWizardContextDeleteForm.php
+++ b/src/Form/PanelizerWizardContextDeleteForm.php
@@ -5,12 +5,40 @@ namespace Drupal\panelizer\Form;
 use Drupal\Core\Form\FormStateInterface;
 use Drupal\Core\Url;
 use Drupal\ctools\Form\ContextDelete;
+use Drupal\Core\Messenger\MessengerInterface;
+use Symfony\Component\DependencyInjection\ContainerInterface;
 
 /**
  * Provides a form for deleting a context.
  */
 class PanelizerWizardContextDeleteForm extends ContextDelete {
 
+  /**
+   * The messenger service.
+   *
+   * @var \Drupal\Core\Messenger\MessengerInterface
+   */
+  protected $messenger;
+
+  /**
+   * Constructs a new PanelizerWizardContextDeleteForm object.
+   *
+   * @param \Drupal\Core\Messenger\MessengerInterface $messenger
+   *   The messenger service.
+   */
+  public function __construct(MessengerInterface $messenger) {
+    $this->messenger = $messenger;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function create(ContainerInterface $container) {
+    return new static(
+      $container->get('messenger')
+    );
+  }
+
   /**
    * {@inheritdoc}
    */
@@ -45,7 +73,7 @@ class PanelizerWizardContextDeleteForm extends ContextDelete {
   public function submitForm(array &$form, FormStateInterface $form_state) {
     $cached_values = $this->getTempstore();
     $context = $cached_values['contexts'][$this->context_id];
-    drupal_set_message($this->t('The static context %label has been removed.', ['%label' => $context['label']]));
+    $this->messenger->addMessage($this->t('The static context %label has been removed.', ['%label' => $context['label']]));
     unset($cached_values['contexts'][$this->context_id]);
     $this->setTempstore($cached_values);
     parent::submitForm($form, $form_state);
diff --git a/src/Form/PanelizerWizardContextForm.php b/src/Form/PanelizerWizardContextForm.php
index 44b6da7..8fe2846 100644
--- a/src/Form/PanelizerWizardContextForm.php
+++ b/src/Form/PanelizerWizardContextForm.php
@@ -8,7 +8,7 @@ use Drupal\Core\Form\FormBuilderInterface;
 use Drupal\Core\Form\FormStateInterface;
 use Drupal\Core\TypedData\TypedDataManagerInterface;
 use Drupal\ctools\Form\ManageContext;
-use Drupal\user\SharedTempStoreFactory;
+use Drupal\Core\TempStore\SharedTempStoreFactory;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 
 /**
@@ -35,7 +35,7 @@ class PanelizerWizardContextForm extends ManageContext {
     return new static(
       $container->get('typed_data_manager'),
       $container->get('form_builder'),
-      $container->get('user.shared_tempstore')
+      $container->get('tempstore.shared')
     );
   }
 
@@ -141,7 +141,7 @@ class PanelizerWizardContextForm extends ManageContext {
     $content = $this->formBuilder->getForm($this->getContextClass($cached_values), $context, $this->getTempstoreId(), $this->machine_name);
     $content['#attached']['library'][] = 'core/drupal.dialog.ajax';
     list(, $route_parameters) = $this->getContextOperationsRouteInfo($cached_values, $this->machine_name, $context);
-    $content['submit']['#attached']['drupalSettings']['ajax'][$content['submit']['#id']]['url'] = $this->url($this->getContextAddRoute($cached_values), $route_parameters, ['query' => [FormBuilderInterface::AJAX_FORM_REQUEST => TRUE]]);
+    $content['submit']['#attached']['drupalSettings']['ajax'][$content['submit']['#id']]['url'] = $this->getUrlGenerator()->generateFromRoute($this->getContextAddRoute($cached_values), $route_parameters, ['query' => [FormBuilderInterface::AJAX_FORM_REQUEST => TRUE]]);
     $response = new AjaxResponse();
     $response->addCommand(new OpenModalDialogCommand($this->t('Add new context'), $content, ['width' => '700']));
     return $response;
diff --git a/src/Panelizer.php b/src/Panelizer.php
index 5169bb1..b33eeb9 100644
--- a/src/Panelizer.php
+++ b/src/Panelizer.php
@@ -318,7 +318,7 @@ class Panelizer implements PanelizerInterface {
       }
 
       // Updates the changed time of the entity, if necessary.
-      if ($entity->getEntityType()->isSubclassOf(EntityChangedInterface::class)) {
+      if ($entity->getEntityType()->entityClassImplements(EntityChangedInterface::class)) {
         $entity->setChangedTime(REQUEST_TIME);
       }
 
diff --git a/src/Tests/Update/PanelizerLayoutIDUpdateTest.php b/src/Tests/Update/PanelizerLayoutIDUpdateTest.php
index f08af8e..0863401 100644
--- a/src/Tests/Update/PanelizerLayoutIDUpdateTest.php
+++ b/src/Tests/Update/PanelizerLayoutIDUpdateTest.php
@@ -2,7 +2,7 @@
 
 namespace Drupal\panelizer\Tests\Update;
 
-use Drupal\system\Tests\Update\UpdatePathTestBase;
+use Drupal\FunctionalTests\Update\UpdatePathTestBase;
 
 /**
  * Tests the updating of Layout IDs.
diff --git a/tests/src/Functional/PanelizerAddDefaultLinkTest.php b/tests/src/Functional/PanelizerAddDefaultLinkTest.php
index b8fb425..2055acd 100644
--- a/tests/src/Functional/PanelizerAddDefaultLinkTest.php
+++ b/tests/src/Functional/PanelizerAddDefaultLinkTest.php
@@ -55,13 +55,13 @@ class PanelizerAddDefaultLinkTest extends BrowserTestBase {
     $this->panelize($content_type);
 
     // Confirm that the content type is now panelized.
-    $this->assertLink('Add a new Panelizer default display');
+    $this->assertSession()->linkExists('Add a new Panelizer default display');
 
     // Un-panelize the content type.
     $this->unpanelize($content_type);
 
     // Confirm that the content type is no longer panelized.
-    $this->assertNoLink('Add a new Panelizer default display');
+    $this->assertSession()->linkNotExists('Add a new Panelizer default display');
   }
 
 }
diff --git a/tests/src/Functional/PanelizerDefaultsTest.php b/tests/src/Functional/PanelizerDefaultsTest.php
index a147f37..b537ace 100644
--- a/tests/src/Functional/PanelizerDefaultsTest.php
+++ b/tests/src/Functional/PanelizerDefaultsTest.php
@@ -73,18 +73,18 @@ class PanelizerDefaultsTest extends BrowserTestBase {
       // to (the panelizer[allow] checkbox in the view display configuration). By
       // default, they aren't.
       $this->drupalGet('node/add/page');
-      $this->assertResponse(200);
-      $this->assertNoFieldByName("panelizer['{$i}][default]");
+      $this->assertSession()->statusCodeEquals(200);
+      $this->assertSession()->fieldNotExists("panelizer['{$i}][default]");
       // Allow user to select panelized modes in UI.
       $this->panelize('page', $view_mode_name, [
         'panelizer[custom]' => TRUE,
         'panelizer[allow]' => TRUE,
       ]);
       $this->drupalGet('node/add/page');
-      $this->assertResponse(200);
-      $this->assertFieldByName("panelizer[{$i}][default]");
-      $this->assertOption("edit-panelizer-{$i}-default", 'default');
-      $this->assertOption("edit-panelizer-{$i}-default", $panelizer_id);
+      $this->assertSession()->statusCodeEquals(200);
+      $this->assertSession()->fieldNotExists("panelizer[{$i}][default]");
+      $this->assertSession()->optionExists("edit-panelizer-{$i}-default", 'default');
+      $this->assertSession()->optionExists("edit-panelizer-{$i}-default", $panelizer_id);
       // Clean up.
       $this->deletePanelizerDefault('page', $view_mode_name, $panelizer_id);
       $this->assertDefaultNotExists('page', $view_mode_name, $panelizer_id);
diff --git a/tests/src/Functional/PanelizerIpeTest.php b/tests/src/Functional/PanelizerIpeTest.php
index 9b04138..c500e3a 100644
--- a/tests/src/Functional/PanelizerIpeTest.php
+++ b/tests/src/Functional/PanelizerIpeTest.php
@@ -99,7 +99,7 @@ class PanelizerIpeTest extends BrowserTestBase {
 
     // Load the test node.
     $this->drupalGet('node/' . $node->id());
-    $this->assertResponse(200);
+    $this->assertSession()->statusCodeEquals(200);
 
     // Confirm the JSON Drupal settings are appropriate.
     $drupalSettings = NULL;
@@ -119,9 +119,9 @@ class PanelizerIpeTest extends BrowserTestBase {
       $this->assertTrue(isset($drupalSettings['panelizer']));
       $this->assertTrue(isset($drupalSettings['panelizer']['entity']));
       $this->assertTrue(isset($drupalSettings['panelizer']['entity']['entity_type_id']));
-      $this->assertEqual($drupalSettings['panelizer']['entity']['entity_type_id'], 'node');
+      $this->assertEquals($drupalSettings['panelizer']['entity']['entity_type_id'], 'node');
       $this->assertTrue(isset($drupalSettings['panelizer']['entity']['entity_id']));
-      $this->assertEqual($drupalSettings['panelizer']['entity']['entity_id'], $node->id());
+      $this->assertEquals($drupalSettings['panelizer']['entity']['entity_id'], $node->id());
       $this->assertTrue(isset($drupalSettings['panelizer']['user_permission']));
       $this->assertTrue(isset($drupalSettings['panelizer']['user_permission']['revert']));
       $this->assertTrue(isset($drupalSettings['panelizer']['user_permission']['save_default']));
@@ -146,7 +146,7 @@ class PanelizerIpeTest extends BrowserTestBase {
 
     // Load the test node.
     $this->drupalGet('node/' . $node->id());
-    $this->assertResponse(200);
+    $this->assertSession()->statusCodeEquals(200);
 
     // Confirm the appropriate DOM structures are present for the IPE.
     $drupalSettings = NULL;
@@ -166,9 +166,9 @@ class PanelizerIpeTest extends BrowserTestBase {
       $this->assertTrue(isset($drupalSettings['panelizer']));
       $this->assertTrue(isset($drupalSettings['panelizer']['entity']));
       $this->assertTrue(isset($drupalSettings['panelizer']['entity']['entity_type_id']));
-      $this->assertEqual($drupalSettings['panelizer']['entity']['entity_type_id'], 'node');
+      $this->assertEquals($drupalSettings['panelizer']['entity']['entity_type_id'], 'node');
       $this->assertTrue(isset($drupalSettings['panelizer']['entity']['entity_id']));
-      $this->assertEqual($drupalSettings['panelizer']['entity']['entity_id'], $node->id());
+      $this->assertEquals($drupalSettings['panelizer']['entity']['entity_id'], $node->id());
       $this->assertTrue(isset($drupalSettings['panelizer']['user_permission']));
       $this->assertTrue(isset($drupalSettings['panelizer']['user_permission']['revert']));
       $this->assertTrue(isset($drupalSettings['panelizer']['user_permission']['save_default']));
@@ -218,9 +218,9 @@ class PanelizerIpeTest extends BrowserTestBase {
       $this->assertTrue(isset($drupalSettings['panelizer']));
       $this->assertTrue(isset($drupalSettings['panelizer']['entity']));
       $this->assertTrue(isset($drupalSettings['panelizer']['entity']['entity_type_id']));
-      $this->assertEqual($drupalSettings['panelizer']['entity']['entity_type_id'], 'node');
+      $this->assertEquals($drupalSettings['panelizer']['entity']['entity_type_id'], 'node');
       $this->assertTrue(isset($drupalSettings['panelizer']['entity']['entity_id']));
-      $this->assertEqual($drupalSettings['panelizer']['entity']['entity_id'], $node->id());
+      $this->assertEquals($drupalSettings['panelizer']['entity']['entity_id'], $node->id());
       $this->assertTrue(isset($drupalSettings['panelizer']['user_permission']));
       $this->assertTrue(isset($drupalSettings['panelizer']['user_permission']['revert']));
       $this->assertTrue(isset($drupalSettings['panelizer']['user_permission']['save_default']));
@@ -273,9 +273,9 @@ class PanelizerIpeTest extends BrowserTestBase {
       $this->assertTrue(isset($drupalSettings['panelizer']));
       $this->assertTrue(isset($drupalSettings['panelizer']['entity']));
       $this->assertTrue(isset($drupalSettings['panelizer']['entity']['entity_type_id']));
-      $this->assertEqual($drupalSettings['panelizer']['entity']['entity_type_id'], 'node');
+      $this->assertEquals($drupalSettings['panelizer']['entity']['entity_type_id'], 'node');
       $this->assertTrue(isset($drupalSettings['panelizer']['entity']['entity_id']));
-      $this->assertEqual($drupalSettings['panelizer']['entity']['entity_id'], $node->id());
+      $this->assertEquals($drupalSettings['panelizer']['entity']['entity_id'], $node->id());
       $this->assertTrue(isset($drupalSettings['panelizer']['user_permission']));
       $this->assertTrue(isset($drupalSettings['panelizer']['user_permission']['revert']));
       $this->assertTrue(isset($drupalSettings['panelizer']['user_permission']['save_default']));
@@ -329,9 +329,9 @@ class PanelizerIpeTest extends BrowserTestBase {
       $this->assertTrue(isset($drupalSettings['panelizer']));
       $this->assertTrue(isset($drupalSettings['panelizer']['entity']));
       $this->assertTrue(isset($drupalSettings['panelizer']['entity']['entity_type_id']));
-      $this->assertEqual($drupalSettings['panelizer']['entity']['entity_type_id'], 'node');
+      $this->assertEquals($drupalSettings['panelizer']['entity']['entity_type_id'], 'node');
       $this->assertTrue(isset($drupalSettings['panelizer']['entity']['entity_id']));
-      $this->assertEqual($drupalSettings['panelizer']['entity']['entity_id'], $node->id());
+      $this->assertEquals($drupalSettings['panelizer']['entity']['entity_id'], $node->id());
       $this->assertTrue(isset($drupalSettings['panelizer']['user_permission']));
       $this->assertTrue(isset($drupalSettings['panelizer']['user_permission']['revert']));
       $this->assertTrue(isset($drupalSettings['panelizer']['user_permission']['save_default']));
@@ -363,12 +363,12 @@ class PanelizerIpeTest extends BrowserTestBase {
 
     // Load the test node.
     $this->drupalGet('node/' . $node->id());
-    $this->assertResponse(200);
+    $this->assertSession()->statusCodeEquals(200);
 
     // Extract the drupalSettings structure and return it.
     $drupalSettings = NULL;
     $matches = [];
-    if (preg_match('@<script type="application/json" data-drupal-selector="drupal-settings-json">([^<]*)</script>@', $this->getRawContent(), $matches)) {
+    if (preg_match('@<script type="application/json" data-drupal-selector="drupal-settings-json">([^<]*)</script>@', $this->getSession()->getPage()->getContent(), $matches)) {
       $drupalSettings = Json::decode($matches[1]);
       $this->verbose('<pre>' . print_r($drupalSettings, TRUE) . '</pre>');
     }
diff --git a/tests/src/Functional/PanelizerNodeFunctionalTest.php b/tests/src/Functional/PanelizerNodeFunctionalTest.php
index fe57812..5182a8e 100644
--- a/tests/src/Functional/PanelizerNodeFunctionalTest.php
+++ b/tests/src/Functional/PanelizerNodeFunctionalTest.php
@@ -53,13 +53,13 @@ class PanelizerNodeFunctionalTest extends BrowserTestBase {
   public function testWizardUI() {
     // Enter the wizard.
     $this->drupalGet('admin/structure/panelizer/edit/node__page__default__default');
-    $this->assertResponse(200);
-    $this->assertText('Wizard Information');
-    $this->assertField('edit-label');
+    $this->assertSession()->statusCodeEquals(200);
+    $this->assertSession()->pageTextContains('Wizard Information');
+    $this->assertSession()->fieldExists('edit-label');
 
     // Contexts step.
     $this->clickLink('Contexts');
-    $this->assertText('@panelizer.entity_context:entity', 'The current entity context is present.');
+    $this->assertSession()->pageTextContains('@panelizer.entity_context:entity', 'The current entity context is present.');
 
     // Layout selection step.
     $this->clickLink('Layout');
@@ -73,57 +73,57 @@ class PanelizerNodeFunctionalTest extends BrowserTestBase {
       'region' => 'content',
     ];
     $this->drupalPostForm(NULL, $edit, t('Add block'));
-    $this->assertResponse(200);
+    $this->assertSession()->statusCodeEquals(200);
 
     // Finish the wizard.
     $this->drupalPostForm(NULL, [], t('Update and save'));
-    $this->assertResponse(200);
+    $this->assertSession()->statusCodeEquals(200);
     // Confirm this returned to the main wizard page.
-    $this->assertText('Wizard Information');
-    $this->assertField('edit-label');
+    $this->assertSession()->pageTextContains('Wizard Information');
+    $this->assertSession()->fieldExists('edit-label');
 
     // Return to the Manage Display page, which is where the Cancel button
     // currently sends you. That's a UX WTF and should be fixed...
     $this->drupalPostForm(NULL, [], t('Cancel'));
-    $this->assertResponse(200);
+    $this->assertSession()->statusCodeEquals(200);
 
     // Confirm the page is back to the content type settings page.
-    $this->assertFieldChecked('edit-panelizer-custom');
+    $this->assertSession()->checkboxChecked('edit-panelizer-custom');
 
     // Now change and save the general setting.
     $edit = [
       'panelizer[custom]' => FALSE,
     ];
     $this->drupalPostForm(NULL, $edit, t('Save'));
-    $this->assertResponse(200);
-    $this->assertNoFieldChecked('edit-panelizer-custom');
+    $this->assertSession()->statusCodeEquals(200);
+    $this->assertSession()->checkboxNotChecked('edit-panelizer-custom');
 
     // Add another block at the Content step and then save changes.
     $this->drupalGet('admin/structure/panelizer/edit/node__page__default__default/content');
-    $this->assertResponse(200);
+    $this->assertSession()->statusCodeEquals(200);
     $this->clickLink('Add new block');
     $this->clickLink('Body');
     $edit = [
       'region' => 'content',
     ];
     $this->drupalPostForm(NULL, $edit, t('Add block'));
-    $this->assertResponse(200);
-    $this->assertText('entity_field:node:body', 'The body block was added successfully.');
+    $this->assertSession()->statusCodeEquals(200);
+    $this->assertSession()->pageTextContains('entity_field:node:body', 'The body block was added successfully.');
     $this->drupalPostForm(NULL, [], t('Save'));
-    $this->assertResponse(200);
+    $this->assertSession()->statusCodeEquals(200);
     $this->clickLink('Content');
-    $this->assertText('entity_field:node:body', 'The body block was saved successfully.');
+    $this->assertSession()->pageTextContains('entity_field:node:body', 'The body block was saved successfully.');
 
     // Check that the Manage Display tab changed now that Panelizer is set up.
     // Also, the field display table should be hidden.
-    $this->assertNoRaw('<div id="field-display-overview-wrapper">');
+    $this->assertSession()->responseNotContains('<div id="field-display-overview-wrapper">');
 
     // Disable Panelizer for the default display mode. This should bring back
     // the field overview table at Manage Display and not display the link to
     // edit the default Panelizer layout.
     $this->unpanelize('page');
-    $this->assertNoLinkByHref('admin/structure/panelizer/edit/node__page__default');
-    $this->assertRaw('<div id="field-display-overview-wrapper">');
+    $this->assertSession()->linkByHrefNotExists('admin/structure/panelizer/edit/node__page__default');
+    $this->assertSession()->responseContains('<div id="field-display-overview-wrapper">');
   }
 
   /**
@@ -145,19 +145,19 @@ class PanelizerNodeFunctionalTest extends BrowserTestBase {
     // Create a node, and check that the IPE is visible on it.
     $node = $this->drupalCreateNode(['type' => 'page']);
     $out = $this->drupalGet('node/' . $node->id());
-    $this->assertResponse(200);
+    $this->assertSession()->statusCodeEquals(200);
     $this->verbose($out);
     $elements = $this->xpath('//*[@id="panels-ipe-content"]');
     if (is_array($elements)) {
-      $this->assertIdentical(count($elements), 1);
+      $this->assertSame(count($elements), 1);
     }
     else {
       $this->fail('Could not parse page content.');
     }
 
     // Check that the block we added is visible.
-    $this->assertText('Panelizer test');
-    $this->assertText('Abracadabra');
+    $this->assertSession()->pageTextContains('Panelizer test');
+    $this->assertSession()->pageTextContains('Abracadabra');
   }
 
 }
diff --git a/tests/src/Functional/PanelizerNodeTranslationsTest.php b/tests/src/Functional/PanelizerNodeTranslationsTest.php
index 714f92e..a4fc23d 100644
--- a/tests/src/Functional/PanelizerNodeTranslationsTest.php
+++ b/tests/src/Functional/PanelizerNodeTranslationsTest.php
@@ -72,13 +72,13 @@ class PanelizerNodeTranslationsTest extends ContentTranslationTestBase {
 
     // Enter the wizard.
     $this->drupalGet("admin/structure/panelizer/edit/{$this->entityTypeId}__{$this->bundle}__default__default");
-    $this->assertResponse(200);
-    $this->assertText('Wizard Information');
-    $this->assertField('edit-label');
+    $this->assertSession()->statusCodeEquals(200);
+    $this->assertSession()->pageTextContains('Wizard Information');
+    $this->assertSession()->buttonExists('edit-label');
 
     // Contexts step.
     $this->clickLink('Contexts');
-    $this->assertText('@panelizer.entity_context:entity', 'The current entity context is present.');
+    $this->assertSession()->pageTextContains('@panelizer.entity_context:entity', 'The current entity context is present.');
 
     // Layout selection step.
     $this->clickLink('Layout');
@@ -93,57 +93,57 @@ class PanelizerNodeTranslationsTest extends ContentTranslationTestBase {
       'region' => 'content',
     ];
     $this->drupalPostForm(NULL, $edit, t('Add block'));
-    $this->assertResponse(200);
+    $this->assertSession()->statusCodeEquals(200);
 
     // Finish the wizard.
     $this->drupalPostForm(NULL, [], t('Update and save'));
-    $this->assertResponse(200);
+    $this->assertSession()->statusCodeEquals(200);
     // Confirm this returned to the main wizard page.
-    $this->assertText('Wizard Information');
-    $this->assertField('edit-label');
+    $this->assertSession()->pageTextContains('Wizard Information');
+    $this->assertSession()->buttonExists('edit-label');
 
     // Return to the Manage Display page, which is where the Cancel button
     // currently sends you. That's a UX WTF and should be fixed...
     $this->drupalPostForm(NULL, [], t('Cancel'));
-    $this->assertResponse(200);
+    $this->assertSession()->statusCodeEquals(200);
 
     // Confirm the page is back to the content type settings page.
-    $this->assertFieldChecked('edit-panelizer-custom');
+    $this->assertSession()->checkboxChecked('edit-panelizer-custom');
 
     // Now change and save the general setting.
     $edit = [
       'panelizer[custom]' => FALSE,
     ];
     $this->drupalPostForm(NULL, $edit, t('Save'));
-    $this->assertResponse(200);
-    $this->assertNoFieldChecked('edit-panelizer-custom');
+    $this->assertSession()->statusCodeEquals(200);
+    $this->assertSession()->checkboxNotChecked('edit-panelizer-custom');
 
     // Add another block at the Content step and then save changes.
     $this->drupalGet("admin/structure/panelizer/edit/{$this->entityTypeId}__{$this->bundle}__default__default/content");
-    $this->assertResponse(200);
+    $this->assertSession()->statusCodeEquals(200);
     $this->clickLink('Add new block');
     $this->clickLink('Body');
     $edit = [
       'region' => 'content',
     ];
     $this->drupalPostForm(NULL, $edit, t('Add block'));
-    $this->assertResponse(200);
-    $this->assertText("entity_field:{$this->entityTypeId}:body", 'The body block was added successfully.');
+    $this->assertSession()->statusCodeEquals(200);
+    $this->assertSession()->pageTextContains("entity_field:{$this->entityTypeId}:body", 'The body block was added successfully.');
     $this->drupalPostForm(NULL, [], t('Save'));
-    $this->assertResponse(200);
+    $this->assertSession()->statusCodeEquals(200);
     $this->clickLink('Content', 1);
-    $this->assertText("entity_field:{$this->entityTypeId}:body", 'The body block was saved successfully.');
+    $this->assertSession()->pageTextContains("entity_field:{$this->entityTypeId}:body", 'The body block was saved successfully.');
 
     // Check that the Manage Display tab changed now that Panelizer is set up.
     // Also, the field display table should be hidden.
-    $this->assertNoRaw('<div id="field-display-overview-wrapper">');
+    $this->assertSession()->responseNotContains('<div id="field-display-overview-wrapper">');
 
     // Disable Panelizer for the default display mode. This should bring back
     // the field overview table at Manage Display and not display the link to
     // edit the default Panelizer layout.
     $this->unpanelize($this->bundle);
-    $this->assertNoLinkByHref("admin/structure/panelizer/edit/{$this->entityTypeId}__{$this->bundle}__default");
-    $this->assertRaw('<div id="field-display-overview-wrapper">');
+    $this->assertSession()->linkByHrefNotExists("admin/structure/panelizer/edit/{$this->entityTypeId}__{$this->bundle}__default");
+    $this->assertSession()->responseContains('<div id="field-display-overview-wrapper">');
   }
 
   /**
@@ -173,25 +173,25 @@ class PanelizerNodeTranslationsTest extends ContentTranslationTestBase {
       ],
     ]);
     $out = $this->drupalGet('node/' . $node->id());
-    $this->assertResponse(200);
+    $this->assertSession()->statusCodeEquals(200);
     $this->verbose($out);
     $elements = $this->xpath('//*[@id="panels-ipe-content"]');
     if (is_array($elements)) {
-      $this->assertIdentical(count($elements), 1);
+      $this->assertSame(count($elements), 1);
     }
     else {
       $this->fail('Could not parse page content.');
     }
 
     // Check that the block we added is visible.
-    $this->assertText('Panelizer test');
-    $this->assertText('Abracadabra');
+    $this->assertSession()->pageTextContains('Panelizer test');
+    $this->assertSession()->pageTextContains('Abracadabra');
 
     // Load the translation page.
     $this->clickLink('Translate');
-    $this->assertText('English (Original language)');
-    $this->assertText('Published');
-    $this->assertText('Not translated');
+    $this->assertSession()->pageTextContains('English (Original language)');
+    $this->assertSession()->pageTextContains('Published');
+    $this->assertSession()->pageTextContains('Not translated');
   }
 
   // @todo Confirm that the different languages of a translated node are loaded properly when using a default display.
diff --git a/tests/src/Functional/PanelizerTermFunctionalTest.php b/tests/src/Functional/PanelizerTermFunctionalTest.php
index 3467f7a..7623b01 100644
--- a/tests/src/Functional/PanelizerTermFunctionalTest.php
+++ b/tests/src/Functional/PanelizerTermFunctionalTest.php
@@ -63,7 +63,7 @@ class PanelizerTermFunctionalTest extends BrowserTestBase {
       'panelizer[custom]' => TRUE,
     ];
     $this->drupalPostForm(NULL, $edit, t('Save'));
-    $this->assertResponse(200);
+    $this->assertSession()->statusCodeEquals(200);
     $this->rebuildAll();
   }
 
@@ -87,19 +87,19 @@ class PanelizerTermFunctionalTest extends BrowserTestBase {
     $term = $this->createTerm();
 
     $out = $this->drupalGet('taxonomy/term/' . $term->id());
-    $this->assertResponse(200);
+    $this->assertSession()->statusCodeEquals(200);
     $this->verbose($out);
     $elements = $this->xpath('//*[@id="panels-ipe-content"]');
     if (is_array($elements)) {
-      $this->assertIdentical(count($elements), 1);
+      $this->assertSame(count($elements), 1);
     }
     else {
       $this->fail('Could not parse page content.');
     }
 
     // Check that the block we added is visible.
-    $this->assertText('Panelizer test');
-    $this->assertText('Abracadabra');
+    $this->assertSession()->pageTextContains('Panelizer test');
+    $this->assertSession()->pageTextContains('Abracadabra');
   }
 
   /**
diff --git a/tests/src/Functional/PanelizerTestTrait.php b/tests/src/Functional/PanelizerTestTrait.php
index 951c0a9..5d5eb33 100644
--- a/tests/src/Functional/PanelizerTestTrait.php
+++ b/tests/src/Functional/PanelizerTestTrait.php
@@ -3,6 +3,7 @@
 namespace Drupal\Tests\panelizer\Functional;
 
 use Drupal\user\Entity\User;
+use Drupal\Core\Entity\Entity\EntityFormDisplay;
 
 /**
  * Contains helper methods for writing functional tests of Panelizer.
@@ -75,25 +76,25 @@ trait PanelizerTestTrait {
    */
   protected function panelize($content_type = 'page', $display = NULL, array $values = []) {
     $this->drupalGet("admin/structure/types");
-    $this->assertResponse(200);
+    $this->assertSession()->statusCodeEquals(200);
 
     $this->drupalGet("admin/structure/types/manage/{$content_type}");
-    $this->assertResponse(200);
+    $this->assertSession()->statusCodeEquals(200);
 
     $path = "admin/structure/types/manage/{$content_type}/display";
     if (!empty($display)) {
       $path .= '/' . $display;
     }
     $this->drupalGet($path);
-    $this->assertResponse(200);
+    $this->assertSession()->statusCodeEquals(200);
 
     $edit = [
       'panelizer[enable]' => TRUE,
     ] + $values;
     $this->drupalPostForm(NULL, $edit, t('Save'));
-    $this->assertResponse(200);
+    $this->assertSession()->statusCodeEquals(200);
 
-    entity_get_form_display('node', $content_type, 'default')
+    EntityFormDisplay::load('node.' . $content_type . '.default')
       ->setComponent('panelizer', [
         'type' => 'panelizer',
       ])
@@ -115,15 +116,15 @@ trait PanelizerTestTrait {
    */
   protected function unpanelize($content_type = 'page', $display = NULL, array $values = []) {
     $this->drupalGet("admin/structure/types/manage/{$content_type}/display/{$display}");
-    $this->assertResponse(200);
+    $this->assertSession()->statusCodeEquals(200);
 
     $edit = [
       'panelizer[enable]' => FALSE,
     ] + $values;
     $this->drupalPostForm(NULL, $edit, t('Save'));
-    $this->assertResponse(200);
+    $this->assertSession()->statusCodeEquals(200);
 
-    entity_get_form_display('node', $content_type, 'default')
+    EntityFormDisplay::load('node.' . $content_type . '.default')
       ->removeComponent('panelizer')
       ->save();
   }
@@ -149,7 +150,7 @@ trait PanelizerTestTrait {
       $path .= '/' . $display;
     }
     $this->drupalGet($path);
-    $this->assertResponse(200);
+    $this->assertSession()->statusCodeEquals(200);
     $this->clickLink('Add a new Panelizer default display');
 
     // Step 1: Enter the default's label and ID.
@@ -158,22 +159,22 @@ trait PanelizerTestTrait {
       'label' => $label,
     ];
     $this->drupalPostForm(NULL, $edit, t('Next'));
-    $this->assertResponse(200);
+    $this->assertSession()->statusCodeEquals(200);
 
     // Step 2: Define contexts.
-    $this->assertUrl("admin/structure/panelizer/add/{$default_id}/contexts", $options);
+    $this->assertSession()->addressEquals("admin/structure/panelizer/add/{$default_id}/contexts", $options);
     $this->drupalPostForm(NULL, [], t('Next'));
-    $this->assertResponse(200);
+    $this->assertSession()->statusCodeEquals(200);
 
     // Step 3: Select layout.
-    $this->assertUrl("admin/structure/panelizer/add/{$default_id}/layout", $options);
+    $this->assertSession()->addressEquals("admin/structure/panelizer/add/{$default_id}/layout", $options);
     $this->drupalPostForm(NULL, [], t('Next'));
-    $this->assertResponse(200);
+    $this->assertSession()->statusCodeEquals(200);
 
     // Step 4: Select content.
-    $this->assertUrl("admin/structure/panelizer/add/{$default_id}/content", $options);
+    $this->assertSession()->addressEquals("admin/structure/panelizer/add/{$default_id}/content", $options);
     $this->drupalPostForm(NULL, [], t('Finish'));
-    $this->assertResponse(200);
+    $this->assertSession()->statusCodeEquals(200);
 
     return $id;
   }
@@ -191,9 +192,9 @@ trait PanelizerTestTrait {
    */
   protected function deletePanelizerDefault($content_type = 'page', $display = 'default', $id = 'default') {
     $this->drupalGet("admin/structure/panelizer/delete/node__{$content_type}__{$display}__{$id}");
-    $this->assertResponse(200);
+    $this->assertSession()->statusCodeEquals(200);
     $this->drupalPostForm(NULL, [], t('Confirm'));
-    $this->assertResponse(200);
+    $this->assertSession()->statusCodeEquals(200);
   }
 
   /**
@@ -208,7 +209,7 @@ trait PanelizerTestTrait {
    *   (optional) The default ID.
    */
   protected function assertDefaultExists($content_type = 'page', $display = 'default', $id = 'default') {
-    $settings = entity_get_display('node', $content_type, $display)
+    $settings = \Drupal::service('entity_display.repository')->getViewDisplay('node', $content_type, $display)
       ->getThirdPartySettings('panelizer');
 
     $display_exists = isset($settings['displays'][$id]);
@@ -227,7 +228,7 @@ trait PanelizerTestTrait {
    *   The default ID.
    */
   protected function assertDefaultNotExists($content_type = 'page', $display = 'default', $id = 'default') {
-    $settings = entity_get_display('node', $content_type, $display)
+    $settings = \Drupal::service('entity_display.repository')->getViewDisplay('node', $content_type, $display)
       ->getThirdPartySettings('panelizer');
 
     $display_exists = isset($settings['displays'][$id]);
diff --git a/tests/src/Functional/PanelizerUserFunctionalTest.php b/tests/src/Functional/PanelizerUserFunctionalTest.php
index 73aa092..02c6d22 100644
--- a/tests/src/Functional/PanelizerUserFunctionalTest.php
+++ b/tests/src/Functional/PanelizerUserFunctionalTest.php
@@ -58,13 +58,13 @@ class PanelizerUserFunctionalTest extends BrowserTestBase {
 
     // Enable Panelizer for this entity.
     $this->drupalGet('admin/config/people/accounts/display');
-    $this->assertResponse(200);
+    $this->assertSession()->statusCodeEquals(200);
     $edit = [
       'panelizer[enable]' => TRUE,
       'panelizer[custom]' => TRUE,
     ];
     $this->drupalPostForm(NULL, $edit, t('Save'));
-    $this->assertResponse(200);
+    $this->assertSession()->statusCodeEquals(200);
 
     // Reload all caches.
     $this->rebuildAll();
@@ -91,21 +91,21 @@ class PanelizerUserFunctionalTest extends BrowserTestBase {
 
     // Check the user entity page.
     $out = $this->drupalGet('user/' . $account->id());
-    $this->assertResponse(200);
+    $this->assertSession()->statusCodeEquals(200);
     $this->verbose($out);
 
     // Verify that 
     $elements = $this->xpath('//*[@id="panels-ipe-content"]');
     if (is_array($elements)) {
-      $this->assertIdentical(count($elements), 1);
+      $this->assertSame(count($elements), 1);
     }
     else {
       $this->fail('Could not parse page content.');
     }
 
     // Check that the block we added is visible.
-    $this->assertText('Panelizer test');
-    $this->assertText('Abracadabra');
+    $this->assertSession()->pageTextContains('Panelizer test');
+    $this->assertSession()->pageTextContains('Abracadabra');
   }
 
 }
diff --git a/tests/src/FunctionalJavascript/PanelizerIntegrationTest.php b/tests/src/FunctionalJavascript/PanelizerIntegrationTest.php
index d9af169..0c70f2d 100644
--- a/tests/src/FunctionalJavascript/PanelizerIntegrationTest.php
+++ b/tests/src/FunctionalJavascript/PanelizerIntegrationTest.php
@@ -2,7 +2,7 @@
 
 namespace Drupal\Tests\panelizer\FunctionalJavascript;
 
-use Drupal\simpletest\ContentTypeCreationTrait;
+use Drupal\Tests\node\Traits\ContentTypeCreationTrait;
 use Drupal\Tests\panels_ipe\FunctionalJavascript\PanelsIPETestBase;
 
 /**