diff --git a/core/drupalci.yml b/core/drupalci.yml
index 2085b9737b..b539aab57e 100644
--- a/core/drupalci.yml
+++ b/core/drupalci.yml
@@ -3,48 +3,11 @@
 # https://www.drupal.org/drupalorg/docs/drupal-ci/customizing-drupalci-testing
 build:
   assessment:
-    validate_codebase:
-      phplint:
-      csslint:
-        halt-on-fail: false
-      eslint:
-        # A test must pass eslinting standards check in order to continue processing.
-        halt-on-fail: false
-      phpcs:
-        # phpcs will use core's specified version of Coder.
-        sniff-all-files: false
-        halt-on-fail: false
     testing:
-      # run_tests task is executed several times in order of performance speeds.
-      # halt-on-fail can be set on the run_tests tasks in order to fail fast.
-      # suppress-deprecations is false in order to be alerted to usages of
-      # deprecated code.
-      run_tests.phpunit:
-        types: 'PHPUnit-Unit'
-        testgroups: '--all'
-        suppress-deprecations: false
-        halt-on-fail: false
-      run_tests.kernel:
-        types: 'PHPUnit-Kernel'
-        testgroups: '--all'
-        suppress-deprecations: false
-        halt-on-fail: false
-      run_tests.simpletest:
-         types: 'Simpletest'
-         testgroups: '--all'
-         suppress-deprecations: false
-         halt-on-fail: false
-      run_tests.functional:
-        types: 'PHPUnit-Functional'
-        testgroups: '--all'
-        suppress-deprecations: false
-        halt-on-fail: false
       run_tests.javascript:
         concurrency: 15
         types: 'PHPUnit-FunctionalJavascript'
-        testgroups: '--all'
+        testgroups: '--class "Drupal\Tests\media_library\FunctionalJavascript\MediaLibraryTest"'
         suppress-deprecations: false
         halt-on-fail: false
-      # Run nightwatch testing.
-      # @see https://www.drupal.org/project/drupal/issues/2869825
-      nightwatchjs:
+        repeat: 30
diff --git a/core/lib/Drupal/Core/Validation/Plugin/Validation/Constraint/PrimitiveTypeConstraint.php b/core/lib/Drupal/Core/Validation/Plugin/Validation/Constraint/PrimitiveTypeConstraint.php
index a18700a04d..a119160037 100644
--- a/core/lib/Drupal/Core/Validation/Plugin/Validation/Constraint/PrimitiveTypeConstraint.php
+++ b/core/lib/Drupal/Core/Validation/Plugin/Validation/Constraint/PrimitiveTypeConstraint.php
@@ -14,6 +14,6 @@
  */
 class PrimitiveTypeConstraint extends Constraint {
 
-  public $message = 'This value should be of the correct primitive type.';
+  public $message = 'This value should be of the correct primitive type. Value: %value, Typed Data: %typed_data, Implements: %implements';
 
 }
diff --git a/core/lib/Drupal/Core/Validation/Plugin/Validation/Constraint/PrimitiveTypeConstraintValidator.php b/core/lib/Drupal/Core/Validation/Plugin/Validation/Constraint/PrimitiveTypeConstraintValidator.php
index be11f80049..cae02f3dfa 100644
--- a/core/lib/Drupal/Core/Validation/Plugin/Validation/Constraint/PrimitiveTypeConstraintValidator.php
+++ b/core/lib/Drupal/Core/Validation/Plugin/Validation/Constraint/PrimitiveTypeConstraintValidator.php
@@ -74,6 +74,8 @@ public function validate($value, Constraint $constraint) {
       // @todo: Provide a good violation message for each problem.
       $this->context->addViolation($constraint->message, [
         '%value' => is_object($value) ? get_class($value) : (is_array($value) ? 'Array' : (string) $value),
+        '%typed_data' => get_class($typed_data),
+        '%implements' => implode(",", class_implements($typed_data)),
       ]);
     }
   }
diff --git a/core/modules/media_library/tests/modules/media_library_show_file_upload_button/css/media_library_show_file_upload_button.css b/core/modules/media_library/tests/modules/media_library_show_file_upload_button/css/media_library_show_file_upload_button.css
new file mode 100644
index 0000000000..090b40dc20
--- /dev/null
+++ b/core/modules/media_library/tests/modules/media_library_show_file_upload_button/css/media_library_show_file_upload_button.css
@@ -0,0 +1,3 @@
+.js .js-hide[name="upload_upload_button"] {
+  display: inline-block;
+}
diff --git a/core/modules/media_library/tests/modules/media_library_show_file_upload_button/media_library_show_file_upload_button.info.yml b/core/modules/media_library/tests/modules/media_library_show_file_upload_button/media_library_show_file_upload_button.info.yml
new file mode 100644
index 0000000000..7bc8c743e1
--- /dev/null
+++ b/core/modules/media_library/tests/modules/media_library_show_file_upload_button/media_library_show_file_upload_button.info.yml
@@ -0,0 +1,5 @@
+name: 'Media Library show upload button'
+type: module
+description: 'CSS to show upload button'
+package: Testing
+core: 8.x
diff --git a/core/modules/media_library/tests/modules/media_library_show_file_upload_button/media_library_show_file_upload_button.libraries.yml b/core/modules/media_library/tests/modules/media_library_show_file_upload_button/media_library_show_file_upload_button.libraries.yml
new file mode 100644
index 0000000000..55b22551cd
--- /dev/null
+++ b/core/modules/media_library/tests/modules/media_library_show_file_upload_button/media_library_show_file_upload_button.libraries.yml
@@ -0,0 +1,5 @@
+drupal.media_library_show_file_upload_button:
+  version: VERSION
+  css:
+    theme:
+      css/media_library_show_file_upload_button.css: {}
diff --git a/core/modules/media_library/tests/modules/media_library_show_file_upload_button/media_library_show_file_upload_button.module b/core/modules/media_library/tests/modules/media_library_show_file_upload_button/media_library_show_file_upload_button.module
new file mode 100644
index 0000000000..5b9957311b
--- /dev/null
+++ b/core/modules/media_library/tests/modules/media_library_show_file_upload_button/media_library_show_file_upload_button.module
@@ -0,0 +1,17 @@
+<?php
+
+function media_library_show_file_upload_button_preprocess_page(&$variables) {
+  $variables['#attached']['library'][] = 'media_library_show_file_upload_button/drupal.media_library_show_file_upload_button';
+}
+
+/**
+ * @param $variables
+ */
+function media_library_show_file_upload_button_preprocess_image_widget(&$variables) {
+  if(empty($variables['data']['width']['#value'])) {
+    $variables['data']['width']['#value'] = 333;
+  }
+  if(empty($variables['data']['height']['#value'])) {
+    $variables['data']['height']['#value'] = 333;
+  }
+}
diff --git a/core/modules/media_library/tests/src/FunctionalJavascript/MediaLibraryTest.php b/core/modules/media_library/tests/src/FunctionalJavascript/MediaLibraryTest.php
index b8c5ba751e..614f3e1ee9 100644
--- a/core/modules/media_library/tests/src/FunctionalJavascript/MediaLibraryTest.php
+++ b/core/modules/media_library/tests/src/FunctionalJavascript/MediaLibraryTest.php
@@ -2,6 +2,8 @@
 
 namespace Drupal\Tests\media_library\FunctionalJavascript;
 
+use Behat\Mink\Exception\ElementNotFoundException;
+use Drupal\Core\File\Exception\FileNotExistsException;
 use Drupal\Core\Url;
 use Drupal\field_ui\FieldUI;
 use Drupal\FunctionalJavascriptTests\WebDriverTestBase;
@@ -34,6 +36,7 @@ class MediaLibraryTest extends WebDriverTestBase {
     'views',
     'views_ui',
     'media_test_oembed',
+    'media_library_show_file_upload_button',
   ];
 
   /**
@@ -91,7 +94,7 @@ protected function setUp() {
   /**
    * Tests that the Media Library's administration page works as expected.
    */
-  public function testAdministrationPage() {
+  public function ztestAdministrationPage() {
     $session = $this->getSession();
     $page = $session->getPage();
     $assert_session = $this->assertSession();
@@ -103,33 +106,32 @@ public function testAdministrationPage() {
     $assert_session->linkExists('Add media');
 
     // Verify that media from two separate types is present.
-    $assert_session->pageTextContains('Dog');
-    $assert_session->pageTextContains('Turtle');
+    $this->waitForText('Dog');
+    $this->waitForText('Turtle');
 
     // Test that users can filter by type.
     $page->selectFieldOption('Media type', 'Type One');
     $page->pressButton('Apply filters');
-    $assert_session->assertWaitOnAjaxRequest();
-    $assert_session->pageTextContains('Dog');
-    $assert_session->pageTextNotContains('Turtle');
+    $this->waitForNoText('Turtle');
+    $this->waitForText('Dog');
     $page->selectFieldOption('Media type', 'Type Two');
     $page->pressButton('Apply filters');
-    $assert_session->assertWaitOnAjaxRequest();
-    $assert_session->pageTextNotContains('Dog');
-    $assert_session->pageTextContains('Turtle');
+    $this->waitForNoText('Dog');
+    $this->waitForText('Turtle');
 
     // Test that selecting elements as a part of bulk operations works.
     $page->selectFieldOption('Media type', '- Any -');
     $page->pressButton('Apply filters');
-    $assert_session->assertWaitOnAjaxRequest();
+    $this->waitForText('Dog');
+
     // This tests that anchor tags clicked inside the preview are suppressed.
     $this->getSession()->executeScript('jQuery(".js-click-to-select-trigger a")[4].click()');
     $this->submitForm([], 'Apply to selected items');
-    $assert_session->pageTextContains('Dog');
-    $assert_session->pageTextNotContains('Cat');
+    $this->waitForNoText('Cat');
+    $this->waitForText('Dog');
     $this->submitForm([], 'Delete');
-    $assert_session->pageTextNotContains('Dog');
-    $assert_session->pageTextContains('Cat');
+    $this->waitForNoText('Dog');
+    $this->waitForText('Cat');
 
     // Test 'Select all media'.
     $this->getSession()->getPage()->checkField('Select all media');
@@ -137,12 +139,12 @@ public function testAdministrationPage() {
     $this->submitForm([], 'Apply to selected items');
     $this->getSession()->getPage()->pressButton('Delete');
 
-    $assert_session->pageTextNotContains('Cat');
-    $assert_session->pageTextNotContains('Turtle');
-    $assert_session->pageTextNotContains('Snake');
+    $this->waitForNoText('Cat');
+    $this->waitForNoText('Turtle');
+    $this->waitForNoText('Snake');
 
     // Test empty text.
-    $assert_session->pageTextContains('No media available.');
+    $this->waitForText('No media available.');
 
     // Verify that the "Table" link is present, click it and check address.
     $assert_session->linkExists('Table');
@@ -155,7 +157,7 @@ public function testAdministrationPage() {
   /**
    * Tests that the widget works as expected when media types are deleted.
    */
-  public function testWidgetWithoutMediaTypes() {
+  public function ztestWidgetWithoutMediaTypes() {
     $assert_session = $this->assertSession();
 
     $user = $this->drupalCreateUser([
@@ -230,8 +232,8 @@ public function testWidgetWithoutMediaTypes() {
     $field_empty_types_message = 'There are no allowed media types configured for this field. <a href="' . $field_empty_types_url->toString() . '">Edit the field settings</a> to select the allowed media types.';
 
     $field_null_types_url = new Url('entity.field_config.node_field_edit_form', [
-        'field_config' => 'node.basic_page.field_null_types_media',
-      ] + $route_bundle_params);
+      'field_config' => 'node.basic_page.field_null_types_media',
+    ] + $route_bundle_params);
     $field_null_types_message = 'There are no allowed media types configured for this field. <a href="' . $field_null_types_url->toString() . '">Edit the field settings</a> to select the allowed media types.';
 
     // Visit a node create page.
@@ -284,31 +286,27 @@ public function testWidgetWithoutMediaTypes() {
   /**
    * Tests that the integration with Views works correctly.
    */
-  public function testViewsAdmin() {
+  public function ztestViewsAdmin() {
     $assert_session = $this->assertSession();
     $page = $this->getSession()->getPage();
 
     // Assert that the widget can be seen and that there are 8 items.
     $this->drupalGet('/admin/structure/views/view/media_library/edit/widget');
-    $assert_session->assertWaitOnAjaxRequest();
-    $assert_session->elementsCount('css', '.media-library-item', 8);
+    $this->waitForElementsCount('css', '.media-library-item', 8);
 
     // Assert that filtering works in live preview.
     $page->find('css', '.media-library-view .view-filters')->fillField('name', 'snake');
     $page->find('css', '.media-library-view .view-filters')->pressButton('Apply filters');
-    $assert_session->assertWaitOnAjaxRequest();
-    $assert_session->elementsCount('css', '.media-library-item', 1);
+    $this->waitForElementsCount('css', '.media-library-item', 1);
 
     // Test the same routine but in the view for the table wiget.
     $this->drupalGet('/admin/structure/views/view/media_library/edit/widget_table');
-    $assert_session->assertWaitOnAjaxRequest();
-    $assert_session->elementsCount('css', '.media-library-item', 8);
+    $this->waitForElementsCount('css', '.media-library-item', 8);
 
     // Assert that filtering works in live preview.
     $page->find('css', '.media-library-view .view-filters')->fillField('name', 'snake');
     $page->find('css', '.media-library-view .view-filters')->pressButton('Apply filters');
-    $assert_session->assertWaitOnAjaxRequest();
-    $assert_session->elementsCount('css', '.media-library-item', 1);
+    $this->waitForElementsCount('css', '.media-library-item', 1);
 
     // We cannot test clicking the 'Insert selected' button in either view
     // because we expect an AJAX error, which would always throw an exception
@@ -321,7 +319,7 @@ public function testViewsAdmin() {
   /**
    * Tests that the widget access works as expected.
    */
-  public function testWidgetAccess() {
+  public function ztestWidgetAccess() {
     $assert_session = $this->assertSession();
 
     $this->drupalLogout();
@@ -403,7 +401,7 @@ public function testWidgetAccess() {
   /**
    * Tests that the Media library's widget works as expected.
    */
-  public function testWidget() {
+  public function ztestWidget() {
     $assert_session = $this->assertSession();
     $page = $this->getSession()->getPage();
 
@@ -411,36 +409,33 @@ public function testWidget() {
     $this->drupalGet('node/add/basic_page');
 
     // Assert that media widget instances are present.
-    $assert_session->pageTextContains('Unlimited media');
-    $assert_session->pageTextContains('Twin media');
-    $assert_session->pageTextContains('Single media type');
-    $assert_session->pageTextContains('Empty types media');
+    $this->waitForText('Unlimited media');
+    $this->waitForText('Twin media');
+    $this->waitForText('Single media type');
+    $this->waitForText('Empty types media');
 
     // Assert generic media library elements.
     $assert_session->elementExists('css', '.media-library-open-button[name^="field_unlimited_media"]')->click();
-    $assert_session->assertWaitOnAjaxRequest();
-    $assert_session->pageTextContains('Add or select media');
+    $this->waitForText('Add or select media');
     $this->assertFalse($assert_session->elementExists('css', '.media-library-select-all')->isVisible());
     $page->find('css', '.ui-dialog-titlebar-close')->click();
 
     // Assert that the media type menu is available when more than 1 type is
     // configured for the field.
     $assert_session->elementExists('css', '.media-library-open-button[name^="field_unlimited_media"]')->click();
-    $assert_session->assertWaitOnAjaxRequest();
-    $menu = $assert_session->elementExists('css', '.media-library-menu');
+    $menu = $this->assertElementExistsAfterWait('css', '.media-library-menu');
     $this->assertTrue($menu->hasLink('Type One'));
     $this->assertFalse($menu->hasLink('Type Two'));
     $this->assertTrue($menu->hasLink('Type Three'));
     $this->assertFalse($menu->hasLink('Type Four'));
     $page->find('css', '.ui-dialog-titlebar-close')->click();
-    $assert_session->assertWaitOnAjaxRequest();
 
     // Assert that the media type menu is available when the target_bundles
     // setting for the entity reference field is null. All types should be
     // allowed in this case.
-    $assert_session->elementExists('css', '.media-library-open-button[name^="field_null_types_media"]')->click();
-    $assert_session->assertWaitOnAjaxRequest();
-    $menu = $assert_session->elementExists('css', '.media-library-menu');
+    $add_media_button = $this->assertElementExistsAfterWait('css', '.media-library-open-button[name^="field_null_types_media"]');
+    $add_media_button->click();
+    $this->assertElementExistsAfterWait('css', '.media-library-menu');
     $this->assertTrue($menu->hasLink('Type One'));
     $this->assertTrue($menu->hasLink('Type Two'));
     $this->assertTrue($menu->hasLink('Type Three'));
@@ -451,8 +446,8 @@ public function testWidget() {
     // Assert that the media type menu is not available when only 1 type is
     // configured for the field.
     $assert_session->elementExists('css', '.media-library-open-button[name^="field_single_media_type"]')->click();
-    $assert_session->assertWaitOnAjaxRequest();
-    $assert_session->elementTextContains('css', '.media-library-selected-count', '0 of 1 item selected');
+    $this->waitForElementTextContains('.media-library-selected-count', '0 of 1 item selected');
+
     // Select a media item, assert the hidden selection field contains the ID of
     // the selected item.
     $checkboxes = $page->findAll('css', '.media-library-view .js-click-to-select-checkbox input');
@@ -465,69 +460,73 @@ public function testWidget() {
 
     // Assert the menu links can be sorted through the widget configuration.
     $assert_session->elementExists('css', '.media-library-open-button[name^="field_twin_media"]')->click();
-    $assert_session->assertWaitOnAjaxRequest();
+    $this->assertElementExistsAfterWait('css', '.media-library-menu');
     $links = $page->findAll('css', '.media-library-menu a');
     $link_titles = [];
     foreach ($links as $link) {
       $link_titles[] = $link->getText();
     }
-    $expected_link_titles = ['Type Three (active tab)', 'Type One', 'Type Two', 'Type Four'];
+    $expected_link_titles = [
+      'Type Three (active tab)',
+      'Type One',
+      'Type Two',
+      'Type Four',
+    ];
     $this->assertSame($link_titles, $expected_link_titles);
     $this->drupalGet('admin/structure/types/manage/basic_page/form-display');
     $assert_session->buttonExists('field_twin_media_settings_edit')->press();
-    $assert_session->assertWaitOnAjaxRequest();
-    $assert_session->buttonExists('Show row weights')->press();
+    $toggle_weight_button = $this->assertElementExistsAfterWait('css', '#field-twin-media .tabledrag-toggle-weight');
+    $toggle_weight_button->press();
     $assert_session->fieldExists('fields[field_twin_media][settings_edit_form][settings][media_types][type_one][weight]')->selectOption(0);
     $assert_session->fieldExists('fields[field_twin_media][settings_edit_form][settings][media_types][type_three][weight]')->selectOption(1);
     $assert_session->fieldExists('fields[field_twin_media][settings_edit_form][settings][media_types][type_four][weight]')->selectOption(2);
     $assert_session->fieldExists('fields[field_twin_media][settings_edit_form][settings][media_types][type_two][weight]')->selectOption(3);
     $assert_session->buttonExists('Save')->press();
-    $assert_session->assertWaitOnAjaxRequest();
-    $assert_session->buttonExists('Hide row weights')->press();
+
     $this->drupalGet('node/add/basic_page');
     $assert_session->elementExists('css', '.media-library-open-button[name^="field_twin_media"]')->click();
-    $assert_session->assertWaitOnAjaxRequest();
+    $this->assertElementExistsAfterWait('css', '.media-library-menu');
     $link_titles = array_map(function ($link) {
       return $link->getText();
     }, $page->findAll('css', '.media-library-menu a'));
-    $this->assertSame($link_titles, ['Type One (active tab)', 'Type Three', 'Type Four', 'Type Two']);
+    $this->assertSame($link_titles, [
+      'Type One (active tab)',
+      'Type Three',
+      'Type Four',
+      'Type Two',
+    ]);
     $page->find('css', '.ui-dialog-titlebar-close')->click();
 
     // Assert media is only visible on the tab for the related media type.
     $assert_session->elementExists('css', '.media-library-open-button[name^="field_unlimited_media"]')->click();
-    $assert_session->assertWaitOnAjaxRequest();
-    $assert_session->pageTextContains('Dog');
-    $assert_session->pageTextContains('Bear');
-    $assert_session->pageTextNotContains('Turtle');
-    $page->clickLink('Type Three');
-    $assert_session->assertWaitOnAjaxRequest();
-    $assert_session->elementExists('named', ['link', 'Type Three (active tab)']);
-    $assert_session->pageTextNotContains('Dog');
-    $assert_session->pageTextNotContains('Bear');
-    $assert_session->pageTextNotContains('Turtle');
+    $this->assertElementExistsAfterWait('css', '.media-library-menu');
+    $this->waitForText('Dog');
+    $this->waitForText('Bear');
+    $this->waitForNoText('Turtle');
+    $this->clickTypeTab('Three');
+    $this->waitForNoText('Dog');
+    $this->waitForNoText('Bear');
+    $this->waitForNoText('Turtle');
     $page->find('css', '.ui-dialog-titlebar-close')->click();
 
     // Assert the exposed name filter of the view.
     $assert_session->elementExists('css', '.media-library-open-button[name^="field_unlimited_media"]')->click();
-    $assert_session->assertWaitOnAjaxRequest();
+    $this->assertElementExistsAfterWait('css', '.media-library-menu');
     $session = $this->getSession();
-    $session->getPage()->fillField('Name', 'Dog');
+    $this->waitForFillField('Name', 'Dog');
     $session->getPage()->pressButton('Apply filters');
-    $assert_session->assertWaitOnAjaxRequest();
-    $assert_session->pageTextContains('Dog');
-    $assert_session->pageTextNotContains('Bear');
-    $session->getPage()->fillField('Name', '');
+    $this->waitForText('Dog');
+    $this->waitForNoText('Bear');
+    $this->waitForFillField('Name', '');
     $session->getPage()->pressButton('Apply filters');
-    $assert_session->assertWaitOnAjaxRequest();
-    $assert_session->pageTextContains('Dog');
-    $assert_session->pageTextContains('Bear');
+    $this->waitForText('Dog');
+    $this->waitForText('Bear');
     $page->find('css', '.ui-dialog-titlebar-close')->click();
 
     // Assert the media library contains header links to switch between the grid
     // and table display.
     $assert_session->elementExists('css', '.media-library-open-button[name^="field_unlimited_media"]')->click();
-    $assert_session->assertWaitOnAjaxRequest();
-    $assert_session->elementExists('css', '.media-library-view .media-library-item--grid');
+    $this->assertElementExistsAfterWait('css', '.media-library-view .media-library-item--grid');
     $assert_session->elementNotExists('css', '.media-library-view .media-library-item--table');
     // Assert the 'Apply filter' button is not moved to the button pane.
     $button_pane = $assert_session->elementExists('css', '.ui-dialog-buttonpane');
@@ -536,101 +535,93 @@ public function testWidget() {
     $assert_session->linkExists('Grid');
     $page->clickLink('Table');
     // Assert the display change is correctly announced for screen readers.
-    $this->assertNotEmpty($assert_session->waitForText('Loading table view.'));
-    $this->assertNotEmpty($assert_session->waitForText('Changed to table view.'));
-    $this->assertNotEmpty($assert_session->waitForElementVisible('css', '.media-library-view .media-library-item--table'));
+    $this->waitForText('Loading table view.');
+    $this->waitForText('Changed to table view.');
+    $this->assertElementExistsAfterWait('css', '.media-library-view .media-library-item--table');
     $assert_session->elementNotExists('css', '.media-library-view .media-library-item--grid');
     // Assert the 'Apply filter' button is not moved to the button pane.
     $assert_session->buttonExists('Insert selected', $button_pane);
     $assert_session->buttonNotExists('Apply filters', $button_pane);
-    $assert_session->pageTextContains('Dog');
-    $assert_session->pageTextContains('Bear');
-    $assert_session->pageTextNotContains('Turtle');
+    $this->waitForText('Dog');
+    $this->waitForText('Bear');
+    $this->waitForNoText('Turtle');
     // Assert the exposed filters can be applied.
-    $page->fillField('Name', 'Dog');
+    $this->waitForFillField('Name', 'Dog');
     $page->pressButton('Apply filters');
-    $assert_session->assertWaitOnAjaxRequest();
-    $assert_session->pageTextContains('Dog');
-    $assert_session->pageTextNotContains('Bear');
-    $assert_session->pageTextNotContains('Turtle');
+    $this->waitForText('Dog');
+    $this->waitForNoText('Bear');
+    $this->waitForNoText('Turtle');
     $page->checkField('Select Dog');
     $assert_session->linkExists('Table');
     $page->clickLink('Grid');
     // Assert the display change is correctly announced for screen readers.
-    $this->assertNotEmpty($assert_session->waitForText('Loading grid view.'));
-    $this->assertNotEmpty($assert_session->waitForText('Changed to grid view.'));
-    $this->assertNotEmpty($assert_session->waitForElementVisible('css', '.media-library-view .media-library-item--grid'));
+    $this->waitForText('Loading grid view.');
+    $this->waitForText('Changed to grid view.');
+    $this->assertElementExistsAfterWait('css', '.media-library-view .media-library-item--grid');
     $assert_session->elementNotExists('css', '.media-library-view .media-library-item--table');
     // Assert the exposed filters are persisted when changing display.
-    $this->assertSame('Dog', $page->findField('Name')->getValue());
-    $assert_session->pageTextContains('Dog');
-    $assert_session->pageTextNotContains('Bear');
-    $assert_session->pageTextNotContains('Turtle');
+    $this->waitForText('Dog');
+    $this->waitForNoText('Bear');
+    $this->waitForNoText('Turtle');
     $assert_session->linkExists('Grid');
     $assert_session->linkExists('Table');
     // Select the item.
     $assert_session->elementExists('css', '.ui-dialog-buttonpane')->pressButton('Insert selected');
-    $this->assertNotEmpty($assert_session->waitForText('Added one media item.'));
-    $assert_session->assertWaitOnAjaxRequest();
+    $this->waitForText('Added one media item.');
     // Ensure that the selection completed successfully.
-    $assert_session->pageTextNotContains('Add or select media');
-    $assert_session->pageTextContains('Dog');
-    $assert_session->pageTextNotContains('Bear');
-    $assert_session->pageTextNotContains('Turtle');
+    $this->waitForNoText('Add or select media');
+    $this->waitForText('Dog');
+    $this->waitForNoText('Bear');
+    $this->waitForNoText('Turtle');
     // Clear the selection.
     $assert_session->elementAttributeContains('css', '.media-library-item__remove', 'aria-label', 'Remove Dog');
     $assert_session->elementExists('css', '.media-library-item__remove')->click();
-    $this->assertNotEmpty($assert_session->waitForText('Removed Dog.'));
-    $assert_session->assertWaitOnAjaxRequest();
+    $this->waitForText('Removed Dog.');
 
     // Assert adding a single media item and removing it.
-    $assert_session->elementExists('css', '.media-library-open-button[name^="field_twin_media"]')->click();
-    $assert_session->assertWaitOnAjaxRequest();
+    $this->assertElementExistsAfterWait('css', '.media-library-open-button[name^="field_twin_media"]')->click();
+    $this->assertElementExistsAfterWait('css', '.media-library-menu');
     $checkboxes = $page->findAll('css', '.media-library-view .js-click-to-select-checkbox input');
     $this->assertGreaterThanOrEqual(1, count($checkboxes));
     $checkboxes[0]->click();
     $assert_session->elementExists('css', '.ui-dialog-buttonpane')->pressButton('Insert selected');
-    $this->assertNotEmpty($assert_session->waitForText('Added one media item.'));
-    $assert_session->assertWaitOnAjaxRequest();
+    $this->waitForText('Added one media item.');
     // Assert the focus is set back on the open button of the media field.
     $this->assertJsCondition('jQuery("#field_twin_media-media-library-wrapper .js-media-library-open-button").is(":focus")');
     $assert_session->elementAttributeContains('css', '.media-library-item__remove', 'aria-label', 'Remove Dog');
     $assert_session->elementExists('css', '.media-library-item__remove')->click();
-    $this->assertNotEmpty($assert_session->waitForText('Removed Dog.'));
-    $assert_session->assertWaitOnAjaxRequest();
+    $this->waitForText('Removed Dog.');
     // Assert the focus is set back on the open button of the media field.
     $this->assertJsCondition('jQuery("#field_twin_media-media-library-wrapper .js-media-library-open-button").is(":focus")');
 
     // Assert we can select the same media item twice.
-    $assert_session->elementExists('css', '.media-library-open-button[name^="field_twin_media"]')->click();
-    $assert_session->assertWaitOnAjaxRequest();
+    $this->assertElementExistsAfterWait('css', '.media-library-open-button[name^="field_twin_media"]')->click();
+    $this->assertElementExistsAfterWait('css', '.media-library-menu');
     $page->checkField('Select Dog');
     $assert_session->elementExists('css', '.ui-dialog-buttonpane')->pressButton('Insert selected');
-    $this->assertNotEmpty($assert_session->waitForText('Added one media item.'));
-    $assert_session->assertWaitOnAjaxRequest();
+    $this->waitForText('Added one media item.');
     $assert_session->elementExists('css', '.media-library-open-button[name^="field_twin_media"]')->click();
-    $assert_session->assertWaitOnAjaxRequest();
+    $this->assertElementExistsAfterWait('css', '.media-library-menu');
     $page->checkField('Select Dog');
     $assert_session->elementExists('css', '.ui-dialog-buttonpane')->pressButton('Insert selected');
-    $this->assertNotEmpty($assert_session->waitForText('Added one media item.'));
-    $assert_session->assertWaitOnAjaxRequest();
+    $this->waitForText('Added one media item.');
     // Assert the same has been added twice and remove the items again.
-    $this->assertCount(2, $page->findAll('css', '.field--name-field-twin-media .media-library-item'));
+    $this->assertElementExistsAfterWait('css', '[name="field_twin_media[selection][1][target_id]"]');
+    $this->waitForElementsCount('css', '.field--name-field-twin-media .media-library-item', 2);
     $assert_session->hiddenFieldValueEquals('field_twin_media[selection][0][target_id]', 4);
     $assert_session->hiddenFieldValueEquals('field_twin_media[selection][1][target_id]', 4);
     $assert_session->elementExists('css', '.media-library-item__remove')->click();
-    $this->assertNotEmpty($assert_session->waitForText('Removed Dog.'));
-    $assert_session->assertWaitOnAjaxRequest();
-    $assert_session->elementExists('css', '.media-library-item__remove')->click();
-    $this->assertNotEmpty($assert_session->waitForText('Removed Dog.'));
-    $assert_session->assertWaitOnAjaxRequest();
+    $this->waitForElementsCount('css', '.media-library-item__remove', 1);
+    $this->waitForText('Removed Dog.');
+    $this->assertElementExistsAfterWait('css', '.media-library-item__remove')->click();
+    $this->waitForText('Removed Dog.');
+    $assert_session->assertNoElementAfterWait('css', '.media-library-item__remove');
 
     // Assert the selection is persistent in the media library modal, and
     // the number of selected items is displayed correctly.
-    $assert_session->elementExists('css', '.media-library-open-button[name^="field_twin_media"]')->click();
-    $assert_session->assertWaitOnAjaxRequest();
+    $this->assertElementExistsAfterWait('css', '.media-library-open-button[name^="field_twin_media"]')->click();
     // Assert the number of selected items is displayed correctly.
-    $assert_session->elementExists('css', '.media-library-selected-count');
+    $this->assertElementExistsAfterWait('css', '.media-library-selected-count');
     $assert_session->elementTextContains('css', '.media-library-selected-count', '0 of 2 items selected');
     $assert_session->elementAttributeContains('css', '.media-library-selected-count', 'role', 'status');
     $assert_session->elementAttributeContains('css', '.media-library-selected-count', 'aria-live', 'polite');
@@ -660,10 +651,8 @@ public function testWidget() {
     $this->assertFalse($checkboxes[3]->hasAttribute('disabled'));
     // The selection should be persisted when navigating to other media types in
     // the modal.
-    $page->clickLink('Type Three');
-    $assert_session->assertWaitOnAjaxRequest();
-    $page->clickLink('Type One');
-    $assert_session->assertWaitOnAjaxRequest();
+    $this->clickTypeTab('Three');
+    $this->clickTypeTab('One');
     $checkboxes = $page->findAll('css', '.media-library-view .js-click-to-select-checkbox input');
     $selected_checkboxes = [];
     foreach ($checkboxes as $checkbox) {
@@ -675,8 +664,7 @@ public function testWidget() {
     $assert_session->hiddenFieldValueEquals('media-library-modal-selection', implode(',', $selected_checkboxes));
     $assert_session->elementTextContains('css', '.media-library-selected-count', '1 of 2 items selected');
     // Add to selection from another type.
-    $page->clickLink('Type Two');
-    $assert_session->assertWaitOnAjaxRequest();
+    $this->clickTypeTab('Two');
     $checkboxes = $page->findAll('css', '.media-library-view .js-click-to-select-checkbox input');
     $this->assertCount(4, $checkboxes);
     $checkboxes[0]->click();
@@ -690,24 +678,22 @@ public function testWidget() {
     $this->assertTrue($checkboxes[2]->hasAttribute('disabled'));
     $this->assertTrue($checkboxes[3]->hasAttribute('disabled'));
     // Assert the checkboxes are also disabled on other pages.
-    $page->clickLink('Type One');
-    $assert_session->assertWaitOnAjaxRequest();
+    $this->clickTypeTab('One');
     $this->assertTrue($checkboxes[0]->hasAttribute('disabled'));
     $this->assertFalse($checkboxes[1]->hasAttribute('disabled'));
     $this->assertTrue($checkboxes[2]->hasAttribute('disabled'));
     $this->assertTrue($checkboxes[3]->hasAttribute('disabled'));
     // Select the items.
     $assert_session->elementExists('css', '.ui-dialog-buttonpane')->pressButton('Insert selected');
-    $this->assertNotEmpty($assert_session->waitForText('Added 2 media items.'));
-    $assert_session->assertWaitOnAjaxRequest();
+    $this->waitForText('Added 2 media items.');
     // Assert the open button is disabled.
-    $open_button = $assert_session->elementExists('css', '.media-library-open-button[name^="field_twin_media"]');
+    $open_button = $this->assertElementExistsAfterWait('css', '.media-library-open-button[name^="field_twin_media"]');
     $this->assertTrue($open_button->hasAttribute('data-disabled-focus'));
     $this->assertTrue($open_button->hasAttribute('disabled'));
     $this->assertJsCondition('jQuery("#field_twin_media-media-library-wrapper .media-library-open-button").is(":disabled")');
 
     // Ensure that the selection completed successfully.
-    $assert_session->pageTextNotContains('Add or select media');
+    $this->waitForNoText('Add or select media');
     $assert_session->elementTextNotContains('css', '#field_twin_media-media-library-wrapper', 'Dog');
     $assert_session->elementTextContains('css', '#field_twin_media-media-library-wrapper', 'Cat');
     $assert_session->elementTextContains('css', '#field_twin_media-media-library-wrapper', 'Turtle');
@@ -716,12 +702,11 @@ public function testWidget() {
     // Remove "Cat" (happens to be the first remove button on the page).
     $assert_session->elementAttributeContains('css', '.media-library-item__remove', 'aria-label', 'Remove Cat');
     $assert_session->elementExists('css', '.media-library-item__remove')->click();
-    $this->assertNotEmpty($assert_session->waitForText('Removed Cat.'));
-    $assert_session->assertWaitOnAjaxRequest();
+    $this->waitForText('Removed Cat.');
     // Assert the focus is set to the wrapper of the other selected item.
     $this->assertJsCondition('jQuery("#field_twin_media-media-library-wrapper .media-library-item").is(":focus")');
+    $this->assertElementExistsAfterWait('css', '[aria-label="Remove Turtle"]');
     $assert_session->elementTextNotContains('css', '#field_twin_media-media-library-wrapper', 'Cat');
-    $assert_session->elementTextContains('css', '#field_twin_media-media-library-wrapper', 'Turtle');
     // Assert the open button is no longer disabled.
     $open_button = $assert_session->elementExists('css', '.media-library-open-button[name^="field_twin_media"]');
     $this->assertFalse($open_button->hasAttribute('data-disabled-focus'));
@@ -730,14 +715,13 @@ public function testWidget() {
 
     // Open the media library again and select another item.
     $assert_session->elementExists('css', '.media-library-open-button[name^="field_twin_media"]')->click();
-    $assert_session->assertWaitOnAjaxRequest();
+    $this->assertElementExistsAfterWait('css', '.media-library-menu');
     $checkboxes = $page->findAll('css', '.media-library-view .js-click-to-select-checkbox input');
     $this->assertGreaterThanOrEqual(1, count($checkboxes));
     $checkboxes[0]->click();
     $assert_session->elementExists('css', '.ui-dialog-buttonpane')->pressButton('Insert selected');
-    $this->assertNotEmpty($assert_session->waitForText('Added one media item.'));
-    $assert_session->assertWaitOnAjaxRequest();
-    $assert_session->elementTextContains('css', '#field_twin_media-media-library-wrapper', 'Dog');
+    $this->waitForText('Added one media item.');
+    $this->assertElementExistsAfterWait('css', '[aria-label="Remove Dog"]');
     $assert_session->elementTextNotContains('css', '#field_twin_media-media-library-wrapper', 'Cat');
     $assert_session->elementTextContains('css', '#field_twin_media-media-library-wrapper', 'Turtle');
     $assert_session->elementTextNotContains('css', '#field_twin_media-media-library-wrapper', 'Snake');
@@ -748,7 +732,7 @@ public function testWidget() {
 
     // Assert the selection is cleared when the modal is closed.
     $assert_session->elementExists('css', '.media-library-open-button[name^="field_unlimited_media"]')->click();
-    $assert_session->assertWaitOnAjaxRequest();
+    $this->assertElementExistsAfterWait('css', '.media-library-menu');
     $checkboxes = $page->findAll('css', '.media-library-view .js-click-to-select-checkbox input');
     $this->assertGreaterThanOrEqual(4, count($checkboxes));
     // Nothing is selected yet.
@@ -769,7 +753,7 @@ public function testWidget() {
     // Close the dialog, reopen it and assert not is selected again.
     $page->find('css', '.ui-dialog-titlebar-close')->click();
     $assert_session->elementExists('css', '.media-library-open-button[name^="field_unlimited_media"]')->click();
-    $assert_session->assertWaitOnAjaxRequest();
+    $this->assertElementExistsAfterWait('css', '.media-library-menu');
     $checkboxes = $page->findAll('css', '.media-library-view .js-click-to-select-checkbox input');
     $this->assertGreaterThanOrEqual(4, count($checkboxes));
     $this->assertFalse($checkboxes[0]->isChecked());
@@ -784,28 +768,28 @@ public function testWidget() {
       'title[0][value]' => 'My page',
       'field_twin_media[selection][0][weight]' => '3',
     ], 'Save');
-    $assert_session->pageTextContains('Basic Page My page has been created');
+    $this->waitForText('Basic Page My page has been created');
     // We removed this item earlier.
-    $assert_session->pageTextNotContains('Cat');
+    $this->waitForNoText('Cat');
     // This item was never selected.
-    $assert_session->pageTextNotContains('Snake');
+    $this->waitForNoText('Snake');
     // "Turtle" should come after "Dog", since we changed the weight.
     $assert_session->elementExists('css', '.field--name-field-twin-media > .field__items > .field__item:last-child:contains("Turtle")');
     // Make sure everything that was selected shows up.
-    $assert_session->pageTextContains('Dog');
-    $assert_session->pageTextContains('Turtle');
+    $this->waitForText('Dog');
+    $this->waitForText('Turtle');
 
     // Re-edit the content and make a new selection.
     $this->drupalGet('node/1/edit');
-    $assert_session->pageTextContains('Dog');
-    $assert_session->pageTextNotContains('Cat');
-    $assert_session->pageTextNotContains('Bear');
-    $assert_session->pageTextNotContains('Horse');
-    $assert_session->pageTextContains('Turtle');
-    $assert_session->pageTextNotContains('Snake');
+    $this->waitForText('Dog');
+    $this->waitForNoText('Cat');
+    $this->waitForNoText('Bear');
+    $this->waitForNoText('Horse');
+    $this->waitForText('Turtle');
+    $this->waitForNoText('Snake');
     $assert_session->elementExists('css', '.media-library-open-button[name^="field_unlimited_media"]')->click();
-    $assert_session->assertWaitOnAjaxRequest();
-    $assert_session->pageTextContains('Add or select media');
+    $this->assertElementExistsAfterWait('css', '.media-library-menu');
+    $this->waitForText('Add or select media');
     // Select all media items of type one (should also contain Dog, again).
     $checkbox_selector = '.media-library-view .js-click-to-select-checkbox input';
     $checkboxes = $page->findAll('css', $checkbox_selector);
@@ -815,27 +799,26 @@ public function testWidget() {
     $checkboxes[2]->click();
     $checkboxes[3]->click();
     $assert_session->elementExists('css', '.ui-dialog-buttonpane')->pressButton('Insert selected');
-    $this->assertNotEmpty($assert_session->waitForText('Added 4 media items.'));
-    $assert_session->assertWaitOnAjaxRequest();
-    $assert_session->pageTextContains('Dog');
-    $assert_session->pageTextContains('Cat');
-    $assert_session->pageTextContains('Bear');
-    $assert_session->pageTextContains('Horse');
-    $assert_session->pageTextContains('Turtle');
-    $assert_session->pageTextNotContains('Snake');
+    $this->waitForText('Added 4 media items.');
+    $this->waitForText('Dog');
+    $this->waitForText('Cat');
+    $this->waitForText('Bear');
+    $this->waitForText('Horse');
+    $this->waitForText('Turtle');
+    $this->waitForNoText('Snake');
     $this->submitForm([], 'Save');
-    $assert_session->pageTextContains('Dog');
-    $assert_session->pageTextContains('Cat');
-    $assert_session->pageTextContains('Bear');
-    $assert_session->pageTextContains('Horse');
-    $assert_session->pageTextContains('Turtle');
-    $assert_session->pageTextNotContains('Snake');
+    $this->waitForText('Dog');
+    $this->waitForText('Cat');
+    $this->waitForText('Bear');
+    $this->waitForText('Horse');
+    $this->waitForText('Turtle');
+    $this->waitForNoText('Snake');
   }
 
   /**
    * Tests that the widget works as expected for anonymous users.
    */
-  public function testWidgetAnonymous() {
+  public function ztestWidgetAnonymous() {
     $assert_session = $this->assertSession();
     $page = $this->getSession()->getPage();
 
@@ -854,17 +837,16 @@ public function testWidgetAnonymous() {
 
     // Add to the unlimited cardinality field.
     $assert_session->elementExists('css', '.media-library-open-button[name^="field_unlimited_media"]')->click();
-    $assert_session->assertWaitOnAjaxRequest();
+    $this->assertElementExistsAfterWait('css', '.media-library-menu');
 
     // Select the first media item (should be Dog).
-    $page->find('css', '.media-library-view .js-click-to-select-checkbox input')->click();
+    $this->assertElementExistsAfterWait('css', '.media-library-view .js-click-to-select-checkbox input')->click();
     $assert_session->elementExists('css', '.ui-dialog-buttonpane')->pressButton('Insert selected');
-    $this->assertNotEmpty($assert_session->waitForText('Added one media item.'));
-    $assert_session->assertWaitOnAjaxRequest();
+    $this->waitForText('Added one media item.');
 
     // Ensure that the selection completed successfully.
-    $assert_session->pageTextNotContains('Add or select media');
-    $assert_session->pageTextContains('Dog');
+    $this->waitForNoText('Add or select media');
+    $this->waitForText('Dog');
 
     // Save the form.
     $assert_session->elementExists('css', '.js-media-library-widget-toggle-weight')->click();
@@ -872,8 +854,8 @@ public function testWidgetAnonymous() {
       'title[0][value]' => 'My page',
       'field_unlimited_media[selection][0][weight]' => '0',
     ], 'Save');
-    $assert_session->pageTextContains('Basic Page My page has been created');
-    $assert_session->pageTextContains('Dog');
+    $this->waitForText('Basic Page My page has been created');
+    $this->waitForText('Dog');
   }
 
   /**
@@ -892,6 +874,9 @@ public function testWidgetUpload() {
       elseif ($extension === 'jpg') {
         $jpg_image = $image;
       }
+      elseif ($extension === 'gif') {
+        $gif_image = $image;
+      }
     }
 
     if (!isset($png_image) || !isset($jpg_image)) {
@@ -913,7 +898,8 @@ public function testWidgetUpload() {
     $this->drupalGet('node/add/basic_page');
     $assert_session->elementExists('css', '.media-library-open-button[name^="field_twin_media"]')->click();
     $assert_session->assertWaitOnAjaxRequest();
-    $assert_session->pageTextContains('Add or select media');
+    $this->assertElementExistsAfterWait('css', '.media-library-menu');
+    $this->waitForText('Add or select media');
 
     // Assert the upload form is not visible for default tab type_three without
     // the proper permissions.
@@ -921,15 +907,12 @@ public function testWidgetUpload() {
 
     // Assert the upload form is not visible for the non-file based media type
     // type_one.
-    $page->clickLink('Type One');
-    $assert_session->assertWaitOnAjaxRequest();
-    $assert_session->elementNotExists('css', '.media-library-add-form');
+    $this->clickTypeTab('One');
 
     // Assert the upload form is visible for type_four.
-    $page->clickLink('Type Four');
-    $assert_session->assertWaitOnAjaxRequest();
-    $assert_session->fieldExists('Add files');
-    $assert_session->pageTextContains('Maximum 2 files.');
+    $this->clickTypeTab('Four');
+    $this->waitForFieldExists('Add files');
+    $this->waitForText('Maximum 2 files.');
 
     // Create a user that can create media for all media types.
     $user = $this->drupalCreateUser([
@@ -951,7 +934,8 @@ public function testWidgetUpload() {
     // Add to the twin media field.
     $assert_session->elementExists('css', '.media-library-open-button[name^="field_twin_media"]')->click();
     $assert_session->assertWaitOnAjaxRequest();
-    $assert_session->pageTextContains('Add or select media');
+    $this->assertElementExistsAfterWait('css', '.media-library-menu');
+    $this->waitForText('Add or select media');
 
     // Assert the upload form is now visible for default tab type_three.
     $assert_session->elementExists('css', '.media-library-add-form');
@@ -960,10 +944,9 @@ public function testWidgetUpload() {
     // Assert we can upload a file to the default tab type_three.
     $assert_session->elementExists('css', '.media-library-add-form--without-input');
     $assert_session->elementNotExists('css', '.media-library-add-form--with-input');
-    $page->attachFileToField('Add files', $this->container->get('file_system')->realpath($png_image->uri));
-    $assert_session->assertWaitOnAjaxRequest();
+    $this->addMediaFileToField('Add files', $this->container->get('file_system')->realpath($png_image->uri));
+    $this->waitForText('The media item has been created but has not yet been saved. Fill in any required fields and save to add it to the media library.');
     $this->assertJsCondition('jQuery(".media-library-add-form__added-media").is(":focus")');
-    $assert_session->pageTextContains('The media item has been created but has not yet been saved. Fill in any required fields and save to add it to the media library.');
     $assert_session->elementAttributeContains('css', '.media-library-add-form__added-media', 'aria-label', 'Added media items');
     $assert_session->elementExists('css', '.media-library-add-form--with-input');
     $assert_session->elementNotExists('css', '.media-library-add-form--without-input');
@@ -981,11 +964,15 @@ public function testWidgetUpload() {
     // Assert the name field contains the filename and the alt text is required.
     $assert_session->fieldValueEquals('Name', $png_image->filename);
     $assert_session->elementExists('css', '.ui-dialog-buttonpane')->pressButton('Save and select');
-    $assert_session->assertWaitOnAjaxRequest();
-    $assert_session->pageTextContains('Alternative text field is required');
-    $page->fillField('Alternative text', $this->randomString());
-    $assert_session->elementExists('css', '.ui-dialog-buttonpane')->pressButton('Save and select');
-    $assert_session->assertWaitOnAjaxRequest();
+    $this->waitForText('Alternative text field is required');
+    $this->waitForFillField('Alternative text', 'alt text 1');
+    $this->assertElementExistsAfterWait('css', '.ui-dialog-buttonpane')->pressButton('Save and select');
+    $this->compensateForFlawedValidation();
+    // Ensure the media item was saved to the library and automatically
+    // selected. The added media items should be in the first position of the
+    // add form.
+    $this->waitForText('1 of 2 items selected');  //RANDOM FAIL
+    $this->waitForText($png_image->filename);
     // The file should be permanent now.
     $files = $file_storage->loadMultiple();
     $file = array_pop($files);
@@ -993,49 +980,42 @@ public function testWidgetUpload() {
     // Load the created media item.
     $media_items = Media::loadMultiple();
     $added_media = array_pop($media_items);
-    // Ensure the media item was saved to the library and automatically
-    // selected. The added media items should be in the first position of the
-    // add form.
-    $assert_session->pageTextContains('Add or select media');
-    $assert_session->pageTextContains($png_image->filename);
+
     $assert_session->fieldValueEquals('media_library_select_form[0]', $added_media->id());
     $assert_session->checkboxChecked('media_library_select_form[0]');
-    $assert_session->pageTextContains('1 of 2 items selected');
+    $this->waitForText('1 of 2 items selected');
     $assert_session->hiddenFieldValueEquals('current_selection', $added_media->id());
     // Ensure the created item is added in the widget.
     $assert_session->elementExists('css', '.ui-dialog-buttonpane')->pressButton('Insert selected');
-    $this->assertNotEmpty($assert_session->waitForText('Added one media item.'));
-    $assert_session->assertWaitOnAjaxRequest();
-    $assert_session->pageTextNotContains('Add or select media');
-    $assert_session->pageTextContains($png_image->filename);
+    $this->waitForText('Added one media item.');
+    $this->waitForText($png_image->filename);
+    $this->waitForNoText('Add or select media');
 
     // Remove the item.
     $assert_session->elementExists('css', '.media-library-item__remove')->click();
-    $assert_session->assertWaitOnAjaxRequest();
-    $assert_session->pageTextNotContains($png_image->filename);
+    $assert_session->assertNoElementAfterWait('css', '.media-library-item__remove');
+    $this->waitForNoText($png_image->filename);
 
     // Assert we can also directly insert uploaded files in the widget.
     $assert_session->elementExists('css', '.media-library-open-button[name^="field_twin_media"]')->click();
     $assert_session->assertWaitOnAjaxRequest();
-    $assert_session->pageTextContains('Add or select media');
-    $page->clickLink('Type Three');
-    $assert_session->assertWaitOnAjaxRequest();
-    $png_uri_2 = $file_system->copy($png_image->uri, 'public://');
-    $page->attachFileToField('Add files', $this->container->get('file_system')->realpath($png_uri_2));
-    $assert_session->assertWaitOnAjaxRequest();
-    $page->fillField('Alternative text', $this->randomString());
-    $assert_session->elementExists('css', '.ui-dialog-buttonpane')->pressButton('Save and insert');
-    $this->assertNotEmpty($assert_session->waitForText('Added one media item.'));
-    $assert_session->assertWaitOnAjaxRequest();
-    $assert_session->pageTextNotContains('Add or select media');
-    $assert_session->pageTextContains($file_system->basename($png_uri_2));
+    $this->assertElementExistsAfterWait('css', '.media-library-menu');
+    $this->waitForText('Add or select media');
+    $this->clickTypeTab('Three');
+    $png_uri_2 = $this->copiedFileUri($png_image->uri);
+    $this->addMediaFileToField('Add files', $this->container->get('file_system')->realpath($png_uri_2));
+    $this->waitForText('Alternative text');
+    $this->waitForFillField('Alternative text', 'alt text 2');
+    $this->saveAndInsert(FALSE);
+    $this->waitForText('Added one media item.');
+    $this->waitForText($file_system->basename($png_uri_2));
+    $this->waitForNoText('Add or select media');
 
     // Also make sure that we can upload to the unlimited cardinality field.
     $assert_session->elementExists('css', '.media-library-open-button[name^="field_unlimited_media"]')->click();
-    $assert_session->assertWaitOnAjaxRequest();
-    $assert_session->pageTextContains('Add or select media');
-    $page->clickLink('Type Three');
-    $assert_session->assertWaitOnAjaxRequest();
+    $this->assertElementExistsAfterWait('css', '.media-library-menu');
+    $this->waitForText('Add or select media');
+    $this->clickTypeTab('Three');
 
     // Select a media item to check if the selection is persisted when adding
     // new items.
@@ -1043,30 +1023,31 @@ public function testWidgetUpload() {
     $checkbox = $page->findField("Select $existing_media_name");
     $selected_item_id = $checkbox->getAttribute('value');
     $checkbox->click();
-    $assert_session->pageTextContains('1 item selected');
+    $this->waitForText('1 item selected');
     $assert_session->hiddenFieldValueEquals('current_selection', $selected_item_id);
-    $png_uri_3 = $file_system->copy($png_image->uri, 'public://');
-    $page->attachFileToField('Add files', $this->container->get('file_system')->realpath($png_uri_3));
-    $assert_session->assertWaitOnAjaxRequest();
+    $png_uri_3 = $this->copiedFileUri($png_image->uri);
+    $this->addMediaFileToField('Add files', $this->container->get('file_system')->realpath($png_uri_3));
+    $this->waitForText('The media item has been created but has not yet been saved.');
     $assert_session->checkboxChecked("Select $existing_media_name");
-    $page->fillField('Name', 'Unlimited Cardinality Image');
-    $page->fillField('Alternative text', $this->randomString());
-    $assert_session->elementExists('css', '.ui-dialog-buttonpane')->pressButton('Save and select');
-    $assert_session->assertWaitOnAjaxRequest();
+    $this->waitForFillField('Name', 'Unlimited Cardinality Image');
+    $this->waitForFillField('Alternative text', 'alt text 3');
+    $this->assertElementExistsAfterWait('css', '.ui-dialog-buttonpane')->pressButton('Save and select');
+    $this->compensateForFlawedValidation();
+    $this->waitForNoText('Save and select'); // RANDOM FAIL TWO
+    // Ensure the media item was saved to the library and automatically
+    // selected. The added media items should be in the first position of the
+    // add form.
+    $this->waitForText('Add or select media');
+    $this->waitForText('Unlimited Cardinality Image');
     // Load the created media item.
     $media_items = Media::loadMultiple();
     $added_media = array_pop($media_items);
     $added_media_name = $added_media->label();
-    // Ensure the media item was saved to the library and automatically
-    // selected. The added media items should be in the first position of the
-    // add form.
-    $assert_session->pageTextContains('Add or select media');
-    $assert_session->pageTextContains('Unlimited Cardinality Image');
     $assert_session->fieldValueEquals('media_library_select_form[0]', $added_media->id());
     $assert_session->checkboxChecked('media_library_select_form[0]');
     // Assert the item that was selected before uploading the file is still
     // selected.
-    $assert_session->pageTextContains('2 items selected');
+    $this->waitForText('2 items selected');
     $assert_session->checkboxChecked("Select $added_media_name");
     $assert_session->checkboxChecked("Select $existing_media_name");
     $assert_session->hiddenFieldValueEquals('current_selection', implode(',', [$selected_item_id, $added_media->id()]));
@@ -1080,114 +1061,118 @@ public function testWidgetUpload() {
     $this->assertCount(2, $selected_checkboxes);
     // Ensure the created item is added in the widget.
     $assert_session->elementExists('css', '.ui-dialog-buttonpane')->pressButton('Insert selected');
-    $this->assertNotEmpty($assert_session->waitForText('Added one media item.'));
-    $assert_session->assertWaitOnAjaxRequest();
-    $assert_session->pageTextNotContains('Add or select media');
-    $assert_session->pageTextContains('Unlimited Cardinality Image');
+    $this->waitForText('Added one media item.');
+    $assert_session->assertNoElementAfterWait('css', '.media-library-wrapper');
+    $this->waitForNoText('Add or select media');
+    $this->waitForText('Unlimited Cardinality Image');
 
     // Assert we can now only upload one more media item.
     $assert_session->elementExists('css', '.media-library-open-button[name^="field_twin_media"]')->click();
     $assert_session->assertWaitOnAjaxRequest();
-    $assert_session->pageTextContains('Add or select media');
-    $page->clickLink('Type Four');
-    $assert_session->assertWaitOnAjaxRequest();
+    $this->assertElementExistsAfterWait('css', '.media-library-menu');
+    $this->waitForText('Add or select media');
+    $this->clickTypeTab('Four');
+    $this->waitForText('One file only.');
     $this->assertFalse($assert_session->fieldExists('Add file')->hasAttribute('multiple'));
-    $assert_session->pageTextContains('One file only.');
 
     // Assert media type four should only allow jpg files by trying a png file
     // first.
-    $png_uri_4 = $file_system->copy($png_image->uri, 'public://');
-    $page->attachFileToField('Add file', $file_system->realpath($png_uri_4));
-    $assert_session->assertWaitOnAjaxRequest();
-    $assert_session->pageTextContains('Only files with the following extensions are allowed');
+    $png_uri_4 = $this->copiedFileUri($png_image->uri);
+    $this->addMediaFileToField('Add file', $file_system->realpath($png_uri_4), FALSE);
+    $this->waitForText('Only files with the following extensions are allowed');
     // Assert that jpg files are accepted by type four.
-    $jpg_uri_2 = $file_system->copy($jpg_image->uri, 'public://');
-    $page->attachFileToField('Add file', $file_system->realpath($jpg_uri_2));
-    $assert_session->assertWaitOnAjaxRequest();
-    $page->fillField('Alternative text', $this->randomString());
+    $jpg_uri_2 = $this->copiedFileUri($jpg_image->uri);
+    $this->addMediaFileToField('Add file', $file_system->realpath($jpg_uri_2));
+    $this->waitForText('Alternative text');
+    $this->waitForFillField('Alternative text', 'alt text 4');
+    $this->compensateForFlawedValidation();
     // The type_four media type has another optional image field.
-    $assert_session->pageTextContains('Extra Image');
-    $jpg_uri_3 = $file_system->copy($jpg_image->uri, 'public://');
-    $page->attachFileToField('Extra Image', $this->container->get('file_system')->realpath($jpg_uri_3));
-    $assert_session->assertWaitOnAjaxRequest();
+    $this->waitForText('Extra Image');
+    $jpg_uri_3 = $this->copiedFileUri($jpg_image->uri);
+    $this->addMediaFileToField('Extra Image', $this->container->get('file_system')->realpath($jpg_uri_3));
+    $this->waitForText($file_system->basename($jpg_uri_3));
+    $this->assertElementExistsAfterWait('css', '.ui-dialog-buttonpane')->pressButton('Save and select');
+    $this->compensateForFlawedValidation();
+    $this->waitForNoText('Save and select');  // RANDOM FAIL
+    // Ensure the media item was saved to the library and automatically
+    // selected.
+    $this->waitForText('Add or select media');
+    $this->waitForText($file_system->basename($jpg_uri_2));
     // Ensure that the extra image was uploaded to the correct directory.
     $files = $file_storage->loadMultiple();
     $file = array_pop($files);
     $this->assertSame('public://type-four-extra-dir', $file_system->dirname($file->getFileUri()));
-    $assert_session->elementExists('css', '.ui-dialog-buttonpane')->pressButton('Save and select');
-    $assert_session->assertWaitOnAjaxRequest();
-    // Ensure the media item was saved to the library and automatically
-    // selected.
-    $assert_session->pageTextContains('Add or select media');
-    $assert_session->pageTextContains($file_system->basename($jpg_uri_2));
+
     // Ensure the created item is added in the widget.
     $assert_session->elementExists('css', '.ui-dialog-buttonpane')->pressButton('Insert selected');
-    $this->assertNotEmpty($assert_session->waitForText('Added one media item.'));
-    $assert_session->assertWaitOnAjaxRequest();
-    $assert_session->pageTextNotContains('Add or select media');
-    $assert_session->pageTextContains($file_system->basename($jpg_uri_2));
+    $this->waitForText('Added one media item.');
+    $this->waitForText($file_system->basename($jpg_uri_2));
+    $this->waitForNoText('Add or select media');
 
     // Assert we can also remove selected items from the selection area in the
     // upload form.
     $assert_session->elementExists('css', '.media-library-open-button[name^="field_unlimited_media"]')->click();
     $assert_session->assertWaitOnAjaxRequest();
-    $assert_session->pageTextContains('Add or select media');
-    $page->clickLink('Type Three');
-    $assert_session->assertWaitOnAjaxRequest();
+    $this->waitForText('Add or select media');
+    $this->assertElementExistsAfterWait('css', '.media-library-menu');
+    $this->clickTypeTab('Three');
     $checkbox = $page->findField("Select $existing_media_name");
     $selected_item_id = $checkbox->getAttribute('value');
     $checkbox->click();
     $assert_session->hiddenFieldValueEquals('current_selection', $selected_item_id);
     $this->assertTrue($assert_session->fieldExists('Add files')->hasAttribute('multiple'));
-    $png_uri_5 = $file_system->copy($png_image->uri, 'public://');
-    $page->attachFileToField('Add files', $this->container->get('file_system')->realpath($png_uri_5));
-    $assert_session->assertWaitOnAjaxRequest();
+    $png_uri_5 = $this->copiedFileUri($png_image->uri);
+    $this->addMediaFileToField('Add files', $this->container->get('file_system')->realpath($gif_image->uri));
+    $this->waitForFillField('Alternative text', 'alt text 5');
+
     // Assert the pre-selected items are shown.
-    $selection_area = $assert_session->elementExists('css', '.media-library-add-form__selected-media');
+    $selection_area = $this->assertElementExistsAfterWait('css', '.media-library-add-form__selected-media');
     $assert_session->elementExists('css', 'summary', $selection_area)->click();
+    $assert_session->assertWaitOnAjaxRequest();
     $assert_session->checkboxChecked("Select $existing_media_name", $selection_area);
     $page->uncheckField("Select $existing_media_name");
-    $page->fillField('Alternative text', $this->randomString());
     $assert_session->hiddenFieldValueEquals('current_selection', '');
     // Close the details element so that clicking the Save and select works.
     // @todo Fix dialog or test so this is not necessary to prevent random
     //   fails. https://www.drupal.org/project/drupal/issues/3055648
     $this->click('details.media-library-add-form__selected-media summary');
-    $assert_session->elementExists('css', '.ui-dialog-buttonpane')->pressButton('Save and select');
     $assert_session->assertWaitOnAjaxRequest();
+    $this->assertElementExistsAfterWait('css', 'details.media-library-add-form__selected-media summary[aria-expanded="false"]');
+    $this->assertElementExistsAfterWait('css', '.ui-dialog-buttonpane')->pressButton('Save and select');
+    $this->compensateForFlawedValidation();
+    $this->waitForNoText('Save and select');
+    $this->waitForText("Select $existing_media_name");
+    $this->waitForText('1 item selected');
     $media_items = Media::loadMultiple();
     $added_media = array_pop($media_items);
     $added_media_name = $added_media->label();
-    $assert_session->pageTextContains('1 item selected');
     $assert_session->checkboxChecked("Select $added_media_name");
     $assert_session->checkboxNotChecked("Select $existing_media_name");
     $assert_session->hiddenFieldValueEquals('current_selection', $added_media->id());
     $assert_session->elementExists('css', '.ui-dialog-buttonpane')->pressButton('Insert selected');
-    $this->assertNotEmpty($assert_session->waitForText('Added one media item.'));
-    $assert_session->assertWaitOnAjaxRequest();
-    $assert_session->pageTextNotContains('Add or select media');
-    $assert_session->pageTextContains($file_system->basename($png_uri_5));
+    $assert_session->assertNoElementAfterWait('css', '.media-library-wrapper');
+    $this->waitForText('Added one media item.');
+    $this->waitForNoText('Add or select media');
+    $this->waitForText($file_system->basename($gif_image->uri));
 
     // Assert removing an uploaded media item before save works as expected.
     $assert_session->elementExists('css', '.media-library-open-button[name^="field_unlimited_media"]')->click();
-    $assert_session->assertWaitOnAjaxRequest();
-    $assert_session->pageTextContains('Add or select media');
-    $page->clickLink('Type Three');
-    $assert_session->assertWaitOnAjaxRequest();
-    $page->attachFileToField('Add files', $this->container->get('file_system')->realpath($png_image->uri));
-    $assert_session->assertWaitOnAjaxRequest();
-    // Assert the focus is shifted to the added media items.
-    $this->assertJsCondition('jQuery(".media-library-add-form__added-media").is(":focus")');
+    $this->assertElementExistsAfterWait('css', '.media-library-menu');
+    $this->clickTypeTab('Three');
+    $this->addMediaFileToField('Add files', $this->container->get('file_system')->realpath($png_image->uri));
     // Assert the media item fields are shown and the vertical tabs are no
     // longer shown.
-    $assert_session->elementExists('css', '.media-library-add-form__fields');
+    $this->assertElementExistsAfterWait('css', '.media-library-add-form__fields', 20000);
+    // Assert the focus is shifted to the added media items.
+    $this->assertJsCondition('jQuery(".media-library-add-form__added-media").is(":focus")');
     $assert_session->elementNotExists('css', '.media-library-menu');
     // Press the 'Remove button' and assert the user is sent back to the media
     // library.
     $assert_session->elementExists('css', '.media-library-add-form__remove-button')->click();
     $assert_session->assertWaitOnAjaxRequest();
+    $this->assertElementExistsAfterWait('css', '.media-library-menu');
     // Assert the remove message is shown.
-    $assert_session->pageTextContains("The media item $png_image->filename has been removed.");
+    $this->waitForText("The media item $png_image->filename has been removed.");
     // Assert the focus is shifted to the first tabbable element of the add
     // form, which should be the source field.
     $this->assertJsCondition('jQuery("#media-library-add-form-wrapper :tabbable").is(":focus")');
@@ -1197,10 +1182,9 @@ public function testWidgetUpload() {
 
     // Assert uploading multiple files.
     $assert_session->elementExists('css', '.media-library-open-button[name^="field_unlimited_media"]')->click();
-    $assert_session->assertWaitOnAjaxRequest();
-    $assert_session->pageTextContains('Add or select media');
-    $page->clickLink('Type Three');
-    $assert_session->assertWaitOnAjaxRequest();
+    $this->assertElementExistsAfterWait('css', '.media-library-menu');
+    $this->waitForText('Add or select media');
+    $this->clickTypeTab('Three');
     // Assert the existing items are remembered when adding and removing media.
     $checkbox = $page->findField("Select $existing_media_name");
     $checkbox->click();
@@ -1210,15 +1194,15 @@ public function testWidgetUpload() {
     $filenames = [];
     $remote_paths = [];
     foreach (range(1, 3) as $i) {
-      $path = $file_system->copy($png_image->uri, 'public://');
+      $path = $this->copiedFileUri($png_image->uri);
       $filenames[] = $file_system->basename($path);
       $remote_paths[] = $driver->uploadFileAndGetRemoteFilePath($file_system->realpath($path));
     }
     $page->findField('Add files')->setValue(implode("\n", $remote_paths));
-    $assert_session->assertWaitOnAjaxRequest();
+
     // Assert the media item fields are shown and the vertical tabs are no
     // longer shown.
-    $assert_session->elementExists('css', '.media-library-add-form__fields');
+    $this->assertElementExistsAfterWait('css', '.media-library-add-form__fields');
     $assert_session->elementNotExists('css', '.media-library-menu');
     // Assert all files have been added.
     $assert_session->fieldValueEquals('media[0][fields][name][0][value]', $filenames[0]);
@@ -1227,16 +1211,20 @@ public function testWidgetUpload() {
     // Assert the pre-selected items are shown.
     $selection_area = $assert_session->elementExists('css', '.media-library-add-form__selected-media');
     $assert_session->elementExists('css', 'summary', $selection_area)->click();
+    $assert_session->assertWaitOnAjaxRequest();
     $assert_session->checkboxChecked("Select $existing_media_name", $selection_area);
     // Set alt texts for items 1 and 2, leave the alt text empty for item 3 to
     // assert the field validation does not stop users from removing items.
-    $page->fillField('media[0][fields][field_media_test_image][0][alt]', $filenames[0]);
-    $page->fillField('media[1][fields][field_media_test_image][0][alt]', $filenames[1]);
+    $this->waitForFillField('media[0][fields][field_media_test_image][0][alt]', $filenames[0]);
+    $this->waitForFillField('media[1][fields][field_media_test_image][0][alt]', $filenames[1]);
     // Remove the second file and assert the focus is shifted to the container
     // of the next media item and field values are still correct.
     $page->pressButton('media-1-remove-button');
-    $this->assertJsCondition('jQuery(".media-library-add-form__media[data-media-library-added-delta=2]").is(":focus")');
-    $assert_session->pageTextContains('The media item ' . $filenames[1] . ' has been removed.');
+    $assert_session->assertWaitOnAjaxRequest();
+    $assert_session->assertNoElementAfterWait('css', '[name="media-1-remove-button"]');
+    $focus_delta = $this->getSession()->evaluateScript("document.activeElement.getAttribute('data-media-library-added-delta')");
+    $this->assertEquals('2', $focus_delta);
+    $this->waitForText('The media item ' . $filenames[1] . ' has been removed.');
     // The second media item should be removed (this has the delta 1 since we
     // start counting from 0).
     $assert_session->elementNotExists('css', '.media-library-add-form__media[data-media-library-added-delta=1]');
@@ -1249,12 +1237,16 @@ public function testWidgetUpload() {
     // Assert the pre-selected items are still shown.
     $selection_area = $assert_session->elementExists('css', '.media-library-add-form__selected-media');
     $assert_session->elementExists('css', 'summary', $selection_area)->click();
+    $assert_session->assertWaitOnAjaxRequest();
     $assert_session->checkboxChecked("Select $existing_media_name", $selection_area);
     // Remove the last file and assert the focus is shifted to the container
     // of the first media item and field values are still correct.
     $page->pressButton('media-2-remove-button');
-    $this->assertJsCondition('jQuery(".media-library-add-form__media[data-media-library-added-delta=0]").is(":focus")');
-    $assert_session->pageTextContains('The media item ' . $filenames[2] . ' has been removed.');
+    $assert_session->assertWaitOnAjaxRequest();
+    $assert_session->assertNoElementAfterWait('css', '[name="media-2-remove-button"]');
+    $focus_delta = $this->getSession()->evaluateScript("document.activeElement.getAttribute('data-media-library-added-delta')");
+    $this->assertEquals('0', $focus_delta);
+    $this->waitForText('The media item ' . $filenames[2] . ' has been removed.');
     $assert_session->elementNotExists('css', '.media-library-add-form__media[data-media-library-added-delta=1]');
     $assert_session->elementNotExists('css', '.media-library-add-form__media[data-media-library-added-delta=2]');
     $media_item_one = $assert_session->elementExists('css', '.media-library-add-form__media[data-media-library-added-delta=0]');
@@ -1265,7 +1257,7 @@ public function testWidgetUpload() {
   /**
    * Tests that oEmbed media can be added in the Media library's widget.
    */
-  public function testWidgetOEmbed() {
+  public function ztestWidgetOEmbed() {
     $this->hijackProviderEndpoints();
     $assert_session = $this->assertSession();
     $page = $this->getSession()->getPage();
@@ -1283,103 +1275,91 @@ public function testWidgetOEmbed() {
 
     // Add to the unlimited media field.
     $assert_session->elementExists('css', '.media-library-open-button[name^="field_unlimited_media"]')->click();
-    $assert_session->assertWaitOnAjaxRequest();
-    $assert_session->pageTextContains('Add or select media');
+    $this->assertElementExistsAfterWait('css', '.media-library-menu');
+    $this->waitForText('Add or select media');
 
     // Assert the default tab for media type one does not have an oEmbed form.
     $assert_session->fieldNotExists('Add Type Five via URL');
 
     // Assert other media types don't have the oEmbed form fields.
-    $page->clickLink('Type Three');
-    $assert_session->assertWaitOnAjaxRequest();
+    $this->clickTypeTab('Three');
+    $this->waitForText('Add files');
     $assert_session->fieldNotExists('Add Type Five via URL');
 
     // Assert we can add an oEmbed video to media type five.
-    $page->clickLink('Type Five');
-    $assert_session->assertWaitOnAjaxRequest();
-    $page->fillField('Add Type Five via URL', $youtube_url);
-    $assert_session->pageTextContains('Allowed providers: YouTube, Vimeo.');
-    $page->pressButton('Add');
-    $assert_session->assertWaitOnAjaxRequest();
-    // Assert the name field contains the remote video title.
+    $this->clickTypeTab('Five');
+    $this->waitForText('Allowed providers: YouTube, Vimeo.');
+    $this->addOembed($youtube_url, 'The media item has been created but has not yet been saved.');
     $assert_session->fieldValueEquals('Name', $youtube_title);
-    $assert_session->elementExists('css', '.ui-dialog-buttonpane')->pressButton('Save and select');
-    $assert_session->assertWaitOnAjaxRequest();
-
-    // Load the created media item.
-    $media_items = Media::loadMultiple();
-    $added_media = array_pop($media_items);
+    $this->assertElementExistsAfterWait('css', '.ui-dialog-buttonpane')->pressButton('Save and select');
+    $this->compensateForFlawedValidation();
+    $this->waitForNoText('Save and select');
 
     // Ensure the media item was saved to the library and automatically
     // selected. The added media items should be in the first position of the
     // add form.
-    $assert_session->pageTextContains('Add or select media');
-    $assert_session->pageTextContains($youtube_title);
+    $this->waitForText('Add or select media');
+    $this->waitForText($youtube_title);
+    // Load the created media item.
+    $media_items = Media::loadMultiple();
+    $added_media = array_pop($media_items);
     $assert_session->fieldValueEquals('media_library_select_form[0]', $added_media->id());
     $assert_session->checkboxChecked('media_library_select_form[0]');
 
     // Assert the created oEmbed video is correctly added to the widget.
     $assert_session->elementExists('css', '.ui-dialog-buttonpane')->pressButton('Insert selected');
-    $this->assertNotEmpty($assert_session->waitForText('Added one media item.'));
-    $assert_session->assertWaitOnAjaxRequest();
-    $assert_session->pageTextNotContains('Add or select media');
-    $assert_session->pageTextContains($youtube_title);
+    $this->waitForText('Added one media item.');
+    $this->waitForText($youtube_title);
+    $this->waitForNoText('Add or select media');
 
     // Open the media library again for the unlimited field and go to the tab
     // for media type five.
     $assert_session->elementExists('css', '.media-library-open-button[name^="field_unlimited_media"]')->click();
-    $assert_session->assertWaitOnAjaxRequest();
-    $assert_session->pageTextContains('Add or select media');
-    $page->clickLink('Type Five');
-    $assert_session->assertWaitOnAjaxRequest();
+    $this->assertElementExistsAfterWait('css', '.media-library-menu');
+    $this->waitForText('Add or select media');
+    $this->clickTypeTab('Five');
 
     // Assert the video is available on the tab.
-    $assert_session->pageTextContains($youtube_title);
+    $this->waitForText($youtube_title);
 
     // Assert we can only add supported URLs.
-    $page->fillField('Add Type Five via URL', 'https://www.youtube.com/');
-    $page->pressButton('Add');
-    $assert_session->assertWaitOnAjaxRequest();
-    $assert_session->pageTextContains('No matching provider found.');
+    $this->addOembed('https://youtube.com', 'No matching provider found.');
+
     // Assert we can not add a video ID that doesn't exist. We need to use a
     // video ID that will not be filtered by the regex, because otherwise the
     // message 'No matching provider found.' will be returned.
-    $page->fillField('Add Type Five via URL', 'https://www.youtube.com/watch?v=PWjcqE3QKBg1');
-    $page->pressButton('Add');
-    $assert_session->assertWaitOnAjaxRequest();
-    $assert_session->pageTextContains('Could not retrieve the oEmbed resource.');
+    $this->addOembed('https://www.youtube.com/watch?v=PWjcqE3QKBg1', 'Could not retrieve the oEmbed resource');
 
     // Select a media item to check if the selection is persisted when adding
     // new items.
-    $checkbox = $page->findField("Select $youtube_title");
+    $checkbox = $this->waitForFieldExists("Select $youtube_title");
     $selected_item_id = $checkbox->getAttribute('value');
     $checkbox->click();
-    $assert_session->pageTextContains('1 item selected');
+    $this->waitForText('1 item selected');
     $assert_session->hiddenFieldValueEquals('current_selection', $selected_item_id);
 
     // Assert we can add a oEmbed video with a custom name.
-    $page->fillField('Add Type Five via URL', $youtube_url);
-    $page->pressButton('Add');
-    $assert_session->assertWaitOnAjaxRequest();
-    $page->fillField('Name', 'Custom video title');
+    $this->addOembed($youtube_url, 'The media item has been created but has not yet been saved.');
+    $this->waitForFillField('Name', 'Custom video title');
     $selection_area = $assert_session->elementExists('css', '.media-library-add-form__selected-media');
     $assert_session->checkboxChecked("Select $youtube_title", $selection_area);
-    $assert_session->elementExists('css', '.ui-dialog-buttonpane')->pressButton('Save and select');
-    $assert_session->assertWaitOnAjaxRequest();
+    $this->assertElementExistsAfterWait('css', '.ui-dialog-buttonpane')->pressButton('Save and select');
+    $this->compensateForFlawedValidation();
+    $this->waitForNoText('Save and select');
 
-    // Load the created media item.
-    $media_items = Media::loadMultiple();
-    $added_media = array_pop($media_items);
     // Ensure the media item was saved to the library and automatically
     // selected. The added media items should be in the first position of the
     // add form.
-    $assert_session->pageTextContains('Add or select media');
-    $assert_session->pageTextContains('Custom video title');
+    $this->waitForText('Add or select media');
+    $this->waitForText('Custom video title');
+    // Load the created media item.
+    $media_items = Media::loadMultiple();
+    $added_media = array_pop($media_items);
     $assert_session->fieldValueEquals('media_library_select_form[0]', $added_media->id());
     $assert_session->checkboxChecked('media_library_select_form[0]');
     // Assert the item that was selected before uploading the file is still
     // selected.
-    $assert_session->pageTextContains('2 items selected');
+    $this->waitForText('2 items selected');
     $assert_session->checkboxChecked("Select Custom video title");
     $assert_session->checkboxChecked("Select $youtube_title");
     $assert_session->hiddenFieldValueEquals('current_selection', implode(',', [$selected_item_id, $added_media->id()]));
@@ -1393,42 +1373,36 @@ public function testWidgetOEmbed() {
     $this->assertCount(2, $selected_checkboxes);
     // Ensure the created item is added in the widget.
     $assert_session->elementExists('css', '.ui-dialog-buttonpane')->pressButton('Insert selected');
-    $this->assertNotEmpty($assert_session->waitForText('Added 2 media items.'));
-    $assert_session->assertWaitOnAjaxRequest();
-    $assert_session->pageTextNotContains('Add or select media');
-    $assert_session->pageTextContains('Custom video title');
+    $this->waitForNoText('Insert selected');
+    $this->waitForNoText('Add or select media');
+    $this->waitForText('Added 2 media items.');
+    $this->waitForText('Custom video title');
 
     // Assert we can directly insert added oEmbed media in the widget.
     $assert_session->elementExists('css', '.media-library-open-button[name^="field_unlimited_media"]')->click();
-    $assert_session->assertWaitOnAjaxRequest();
-    $assert_session->pageTextContains('Add or select media');
-    $page->clickLink('Type Five');
-    $assert_session->assertWaitOnAjaxRequest();
-    $page->fillField('Add Type Five via URL', $vimeo_url);
-    $page->pressButton('Add');
-    $assert_session->assertWaitOnAjaxRequest();
-    $assert_session->elementExists('css', '.ui-dialog-buttonpane')->pressButton('Save and insert');
-    $this->assertNotEmpty($assert_session->waitForText('Added one media item.'));
-    $assert_session->assertWaitOnAjaxRequest();
-    $assert_session->pageTextNotContains('Add or select media');
-    $assert_session->pageTextContains($vimeo_title);
+    $this->assertElementExistsAfterWait('css', '.media-library-menu');
+    $this->waitForText('Add or select media');
+    $this->clickTypeTab('Five');
+    $this->addOembed($vimeo_url, 'The media item has been created but has not yet been saved.');
+    $this->saveAndInsert(FALSE);
+    $this->compensateForFlawedValidation();
+    $this->waitForText('Added one media item.');
+    $this->waitForNoText('Add or select media');
+    $this->waitForText($vimeo_title);
 
     // Assert we can remove selected items from the selection area in the oEmbed
     // form.
     $assert_session->elementExists('css', '.media-library-open-button[name^="field_unlimited_media"]')->click();
-    $assert_session->assertWaitOnAjaxRequest();
-    $assert_session->pageTextContains('Add or select media');
-    $page->clickLink('Type Five');
-    $assert_session->assertWaitOnAjaxRequest();
+    $this->assertElementExistsAfterWait('css', '.media-library-menu');
+    $this->waitForText('Add or select media');
+    $this->clickTypeTab('Five');
     $checkbox = $page->findField("Select $vimeo_title");
     $selected_item_id = $checkbox->getAttribute('value');
     $checkbox->click();
     $assert_session->hiddenFieldValueEquals('current_selection', $selected_item_id);
-    $page->fillField('Add Type Five via URL', $youtube_url);
-    $page->pressButton('Add');
-    $assert_session->assertWaitOnAjaxRequest();
-    $page->fillField('Name', 'Another video');
-    $selection_area = $assert_session->elementExists('css', '.media-library-add-form__selected-media');
+    $this->addOembed($youtube_url, 'The media item has been created but has not yet been saved.');
+    $this->waitForFillField('Name', 'Another video');
+    $selection_area = $this->assertElementExistsAfterWait('css', '.media-library-add-form__selected-media');
     $assert_session->elementExists('css', 'summary', $selection_area)->click();
     $assert_session->checkboxChecked("Select $vimeo_title", $selection_area);
     $page->uncheckField("Select $vimeo_title");
@@ -1437,41 +1411,40 @@ public function testWidgetOEmbed() {
     // @todo Fix dialog or test so this is not necessary to prevent random
     //   fails. https://www.drupal.org/project/drupal/issues/3055648
     $this->click('details.media-library-add-form__selected-media summary');
-    $assert_session->elementExists('css', '.ui-dialog-buttonpane')->pressButton('Save and select');
-    $assert_session->assertWaitOnAjaxRequest();
-    $media_items = Media::loadMultiple();
-    $added_media = array_pop($media_items);
-    $assert_session->pageTextContains('1 item selected');
+    $this->assertElementExistsAfterWait('css', '.ui-dialog-buttonpane')->pressButton('Save and select');
+    $this->compensateForFlawedValidation();
+    $this->waitForNoText('Save and select');
+
+    $this->waitForText("Select $vimeo_title");
+    $this->waitForText('1 item selected');
     $assert_session->checkboxChecked('Select Another video');
     $assert_session->checkboxNotChecked("Select $vimeo_title");
+    $media_items = Media::loadMultiple();
+    $added_media = array_pop($media_items);
     $assert_session->hiddenFieldValueEquals('current_selection', $added_media->id());
     $assert_session->elementExists('css', '.ui-dialog-buttonpane')->pressButton('Insert selected');
-    $this->assertNotEmpty($assert_session->waitForText('Added one media item.'));
-    $assert_session->assertWaitOnAjaxRequest();
-    $assert_session->pageTextNotContains('Add or select media');
-    $assert_session->pageTextContains('Another video');
+    $this->waitForNoText('Insert selected');
+    $this->waitForText('Added one media item.');
+    $this->waitForText('Another video');
 
     // Assert removing an added oEmbed media item before save works as expected.
     $assert_session->elementExists('css', '.media-library-open-button[name^="field_unlimited_media"]')->click();
-    $assert_session->assertWaitOnAjaxRequest();
-    $assert_session->pageTextContains('Add or select media');
-    $page->clickLink('Type Five');
-    $assert_session->assertWaitOnAjaxRequest();
-    $page->fillField('Add Type Five via URL', $youtube_url);
-    $page->pressButton('Add');
-    $assert_session->assertWaitOnAjaxRequest();
+    $this->assertElementExistsAfterWait('css', '.media-library-menu');
+    $this->waitForText('Add or select media');
+    $this->clickTypeTab('Five');
+    $this->addOembed($youtube_url, 'The media item has been created but has not yet been saved.');
     // Assert the focus is shifted to the added media items.
     $this->assertJsCondition('jQuery(".media-library-add-form__added-media").is(":focus")');
     // Assert the media item fields are shown and the vertical tabs are no
     // longer shown.
-    $assert_session->elementExists('css', '.media-library-add-form__fields');
+    $this->assertElementExistsAfterWait('css', '.media-library-add-form__fields');
     $assert_session->elementNotExists('css', '.media-library-menu');
     // Press the 'Remove button' and assert the user is sent back to the media
     // library.
     $assert_session->elementExists('css', '.media-library-add-form__remove-button')->click();
-    $assert_session->assertWaitOnAjaxRequest();
+    $this->assertElementExistsAfterWait('css', '.media-library-menu');
     // Assert the remove message is shown.
-    $assert_session->pageTextContains("The media item $youtube_title has been removed.");
+    $this->waitForText("The media item $youtube_title has been removed.");
     // Assert the focus is shifted to the first tabbable element of the add
     // form, which should be the source field.
     $this->assertJsCondition('jQuery("#media-library-add-form-wrapper :tabbable").is(":focus")');
@@ -1479,4 +1452,404 @@ public function testWidgetOEmbed() {
     $assert_session->elementExists('css', '.media-library-menu');
   }
 
+  /**
+   * Asserts that text does not appear on page after a wait.
+   *
+   * @todo replace with whatever gets added in
+   *   https://www.drupal.org/node/3061852
+   */
+  protected function waitForNoText($text, $timeout = 10000) {
+    $page = $this->getSession()->getPage();
+    $result = $page->waitFor($timeout / 1000, function () use ($page, $text) {
+      $actual = preg_replace('/\s+/u', ' ', $page->getText());
+      $regex = '/' . preg_quote($text, '/') . '/ui';
+      return (bool) !preg_match($regex, $actual);
+    });
+    if (empty($result)) {
+      $this->htmlOutput();
+      $filename = $this->htmlOutputDirectory . '/' . $this->htmlOutputClassName . '-' . $this->htmlOutputCounter . '-' . time() . '-NOTEXT.jpg';
+      $this->createScreenshot($filename);
+    }
+    $this->assertNotEmpty($result, "\"$text\" was found but shouldn't be there.");
+  }
+
+  /**
+   * Asserts that text appears on page after a wait.
+   *
+   * @todo replace with whatever gets added in
+   *   https://www.drupal.org/node/3061852
+   */
+  protected function waitForText($text, $timeout = 20000) {
+    $assert_session = $this->assertSession();
+    $result = $assert_session->waitForText($text, $timeout);
+    if (empty($result)) {
+      $this->htmlOutput();
+      $filename = $this->htmlOutputDirectory . '/' . $this->htmlOutputClassName . '-' . $this->htmlOutputCounter . '-' . time() . '-WAIT4TEXT.jpg';
+      $this->createScreenshot($filename);
+    }
+    $this->assertNotEmpty($result, "\"$text\" not found");
+  }
+
+  /**
+   * Asserts that text appears on page after a wait.
+   *
+   * @todo replace with whatever gets added in
+   *   https://www.drupal.org/node/3061852
+   */
+  protected function waitForElementTextContains($selector, $text) {
+    $assert_session = $this->assertSession();
+    $element = $assert_session->waitForElement('css', "$selector:contains('$text')");
+    $this->assertNotEmpty($element);
+  }
+
+  /**
+   * Waits for the specified selector and returns it if not empty.
+   *
+   * @param string $selector
+   *   The selector engine name. See ElementInterface::findAll() for the
+   *   supported selectors.
+   * @param string|array $locator
+   *   The selector locator.
+   * @param int $timeout
+   *   (Optional) Timeout in milliseconds, defaults to 10000.
+   *
+   * @return \Behat\Mink\Element\NodeElement
+   *   The page element node if found. If not found, the test fails.
+   *
+   * @todo replace with whatever gets added in
+   *   https://www.drupal.org/node/3061852
+   */
+  protected function assertElementExistsAfterWait($selector, $locator, $timeout = 10000) {
+    $assert_session = $this->assertSession();
+    $element = $assert_session->waitForElement($selector, $locator, $timeout);
+    if (empty($element)) {
+      $this->htmlOutput();
+      $filename = $this->htmlOutputDirectory . '/' . $this->htmlOutputClassName . '-' . $this->htmlOutputCounter . '-' . time() . '-ELEMENT-NOT-EXISTS.jpg';
+      $this->createScreenshot($filename);
+    }
+    $this->assertNotEmpty($element);
+    return $element;
+  }
+
+  /**
+   * Clicks a media type tab and waits for it to appear.
+   */
+  protected function clickTypeTab($type) {
+    $page = $this->getSession()->getPage();
+    $assert_session = $this->assertSession();
+    $lowercase_type = strtolower($type);
+
+    try {
+      $assert_session->elementExists('css', ".media-library-menu-type-$lowercase_type .active-tab");
+      // There is nothing to do as the type is already active.
+      return;
+    }
+    catch (ElementNotFoundException $e) {
+    }
+
+    $page->clickLink($type);
+    $this->assertElementExistsAfterWait('css', ".media-library-menu-type-$lowercase_type .active-tab");
+    $assert_session->waitForElementVisible('css', "[action='/admin/content/media-widget/type_$lowercase_type']");
+  }
+
+  /**
+   * Checks for a specified number of specific elements on page after wait.
+   *
+   * @param string $selector_type
+   *   Element selector type (css, xpath)
+   * @param string|array $selector
+   *   Element selector.
+   * @param int $count
+   *   Expected count.
+   * @param int $timeout
+   *   (Optional) Timeout in milliseconds, defaults to 10000.
+   *
+   * @todo replace with whatever gets added in
+   *   https://www.drupal.org/node/3061852
+   */
+  protected function waitForElementsCount($selector_type, $selector, $count, $timeout = 10000) {
+    $assert_session = $this->assertSession();
+    $page = $this->getSession()->getPage();
+
+    $start = microtime(TRUE);
+    $end = $start + ($timeout / 1000);
+    do {
+      $nodes = $page->findAll($selector_type, $selector);
+      if (count($nodes) === $count) {
+        return;
+      }
+      usleep(100000);
+    } while (microtime(TRUE) < $end);
+
+    $assert_session->elementsCount($selector_type, $selector, $count);
+  }
+
+  /**
+   * Checks for the existence of a field on page after wait.
+   *
+   * @param string $field
+   *   The field to find.
+   * @param int $timeout
+   *   (Optional) Timeout in milliseconds, defaults to 10000.
+   *
+   * @return \Behat\Mink\Element\NodeElement|null
+   *   The element if found, otherwise null.
+   *
+   * @todo replace with whatever gets added in
+   *   https://www.drupal.org/node/3061852
+   */
+  protected function waitForFieldExists($field, $timeout = 10000) {
+    $assert_session = $this->assertSession();
+    $page = $this->getSession()->getPage();
+
+    $start = microtime(TRUE);
+    $end = $start + ($timeout / 1000);
+    do {
+      $node = $page->findField($field);
+      if (!is_null($node)) {
+        return $node;
+      }
+      usleep(100000);
+    } while (microtime(TRUE) < $end);
+
+    $this->htmlOutput();
+    $filename = $this->htmlOutputDirectory . '/' . $this->htmlOutputClassName . '-' . $this->htmlOutputCounter . '-' . time() . '.jpg';
+    $this->createScreenshot($filename);
+
+    return $assert_session->fieldExists($field);
+  }
+
+  /**
+   * Checks if a field exists and provides it a value.
+   *
+   * @param string $field
+   *   The field to find.
+   * @param string $value
+   *   The value entered in the field.
+   * @param int $timeout
+   *   (Optional) Timeout in milliseconds, defaults to 10000.
+   *
+   * @todo replace with whatever gets added in
+   *   https://www.drupal.org/node/3061852
+   */
+  protected function waitForFillField($field, $value, $timeout = 10000) {
+    if ($field = $this->waitForFieldExists($field, $timeout)) {
+      $field->setValue($value);
+    }
+  }
+
+  /**
+   * Makes multiple attempts to add an oEmbed to the media library.
+   *
+   * The oEmbed test relies on a consistent response from the external service
+   * that the media is being embedded from. On occasion, the expected response
+   * does not happen.
+   *
+   * @param string $video_url
+   *   The oEmbed URL.
+   * @param string $text
+   *   Text to look for to confirm successful addition.
+   * @param int $timeout
+   *   Timeout in milliseconds, defaults to 10000.
+   */
+  protected function addOembed($video_url, $text, $timeout = 20000) {
+    $assert_session = $this->assertSession();
+
+    $this->waitForFillField('Add Type Five via URL', $video_url);
+    $this->getSession()->getPage()->pressButton('Add');
+    $result = $assert_session->waitForText($text, $timeout);
+    $this->assertNotEmpty($result, "\"$text\" not found");
+  }
+
+  /**
+   * Attach file field with specified locator and confirms file was uploaded.
+   *
+   * In some test instances, the addition of an item to the media library takes
+   * unexpectedly long. To prevent tests from failing when the addition takes
+   * long, this method does not complete until the item has been added to the
+   * media library. This is also necessary because some tests check for the
+   * ID of the newly uploaded content immediatley after upload and this
+   * guarantees it has been added.
+   *
+   * @param string $locator
+   *   Input id, name or label.
+   * @param string $path
+   *   Path to file.
+   * @param bool $expect_completion
+   *   If the uploaded is expected to be successful.
+   *
+   * @todo replace with whatever gets added in
+   *   https://www.drupal.org/node/3061852
+   */
+  public function addMediaFileToField($locator, $path, $expect_completion = TRUE) {
+    $page = $this->getSession()->getPage();
+    $assert_session = $this->assertSession();
+
+    $this->waitForFieldExists($locator);
+    $file_storage = $this->container->get('entity_type.manager')->getStorage('file');
+    $current_number_of_files = count($file_storage->loadMultiple());
+    $page->attachFileToField($locator, $path);
+    if ($expect_completion) {
+      $this->waitForFileUploaded($current_number_of_files);
+      $alternative_text_field = $assert_session->waitForText('Alternative text');
+      if (empty($alternative_text_field) && empty($page->find('css', ':contains("No file chosen")')) && !empty($page->findButton('Upload'))) {
+        $page->pressButton('Upload');
+      }
+    }
+    $condition = <<<JS
+      (function() {
+        function isAjaxing(instance) {
+          return instance && instance.ajaxing === true;
+        }
+        return (
+          // Assert no AJAX request is running (via jQuery or Drupal) and no
+          // animation is running.
+          (typeof jQuery === 'undefined' || (jQuery.active === 0 && jQuery(':animated').length === 0)) &&
+          (typeof Drupal === 'undefined' || typeof Drupal.ajax === 'undefined' || !Drupal.ajax.instances.some(isAjaxing))
+        );
+      }());
+JS;
+    $script = <<<JS
+      (function() {
+        var active_instances = Drupal.ajax.instances.filter(function(instance) {
+            return instance && instance.ajaxing === true;
+        });
+        return active_instances.reduce(function(carry, item) {
+            return carry + '|||' + item.method + '-----' + item.wrapper;
+        }, '');
+      }());
+JS;
+    $result = $this->getSession()->wait(10000, $condition);
+    if (!$result) {
+      $trace = $this->getSession()->evaluateScript($script);
+      $this->htmlOutput();
+      $filename = $this->htmlOutputDirectory . '/' . $this->htmlOutputClassName . '-' . $this->htmlOutputCounter . '-UNFINISHED-ADD-MEDIA.jpg';
+      $this->createScreenshot($filename);
+      throw new \RuntimeException('UPLOAD DIDNT STOP ' . $trace);
+    }
+    $assert_session->assertWaitOnAjaxRequest();
+  }
+
+  /**
+   * Clicks "Save and Insert" and confirms addition to the media library.
+   *
+   * In some test instances, the addition of an item to the media library takes
+   * unexpectedly long. To prevent tests from failing when the addition takes
+   * long, this method does not complete until the item has been added to the
+   * media library. This is also necessary because some tests check for the
+   * ID of the newly uploaded content immediatley after upload and this
+   * guarantees it has been added.
+   *
+   * @param bool $expect_completion
+   *   True if it is expected for a new media item to be added.
+   */
+  protected function saveAndInsert($expect_completion = TRUE) {
+    $file_storage = $this->container->get('entity_type.manager')->getStorage('file');
+    $current_number_of_files = count($file_storage->loadMultiple());
+    $this->assertElementExistsAfterWait('css', '.ui-dialog-buttonpane')->pressButton('Save and insert');
+    if ($expect_completion) {
+      $this->waitForFileUploaded($current_number_of_files);
+    }
+    $this->compensateForFlawedValidation(10000, 1, 'insert');
+  }
+
+  /**
+   * Waits to see if a new file has been uploaded.
+   *
+   * @param int $number_of_files
+   *   The number of files prior to the upload.
+   * @param int $timeout
+   *   (Optional) Timeout in milliseconds, defaults to 10000.
+   *
+   * @throws FileNotExistsException
+   *   If no new file uploaded.
+   *
+   * @todo replace with whatever gets added in
+   *   https://www.drupal.org/node/3061852
+   */
+  protected function waitForFileUploaded($number_of_files, $timeout = 10000) {
+    $start = microtime(TRUE);
+    $end = $start + ($timeout / 1000);
+
+    $file_storage = $this->container->get('entity_type.manager')->getStorage('file');
+
+    do {
+      $new_number_of_files = count($file_storage->loadMultiple());
+      if ($new_number_of_files > $number_of_files) {
+        return;
+      }
+      usleep(100000);
+    } while (microtime(TRUE) < $end);
+
+    throw new FileNotExistsException("The file was not uploaded.");
+  }
+
+  protected function copiedFileUri($uri, $count = 0) {
+    $file_system = $this->container->get('file_system');
+
+    $new_uri = $file_system->copy($uri, 'public://');
+    $original_hash = sha1_file($uri);
+    $new_hash = sha1_file($new_uri);
+    if ($original_hash === $new_hash) {
+      return $new_uri;
+    }
+    elseif ($count < 5) {
+      $count++;
+      $this->copiedFileUri($uri, $count);
+    }
+    throw new FileNotExistsException("The file did not copy properly");
+
+  }
+
+  /**
+   * Checks if alt text field did not successfully validate and try again.
+   *
+   * Technically this method should not be necessary, but in ~2% of tests the
+   * tests fail because validation fails for the alt text field even though it
+   * was filled correctly.
+   */
+  protected function compensateForFlawedValidation($timeout = 10000, $count = 1, $operation = 'select') {
+    $assert_session = $this->assertSession();
+    $page = $this->getSession()->getPage();
+
+    if ($count < 2 && ($assert_session->waitForText('This value should be of the correct primitive type', $timeout) || $assert_session->waitForText('Alternative text field is required', $timeout))) {
+      $count++;
+      $this->htmlOutput();
+      $filename = $this->htmlOutputDirectory . '/' . $this->htmlOutputClassName . '-' . $this->htmlOutputCounter . '-ALT' . $count . '.jpg';
+      $this->createScreenshot($filename);
+    }
+    $condition = <<<JS
+      (function() {
+        function isAjaxing(instance) {
+          return instance && instance.ajaxing === true;
+        }
+        return (
+          // Assert no AJAX request is running (via jQuery or Drupal) and no
+          // animation is running.
+          (typeof jQuery === 'undefined' || (jQuery.active === 0 && jQuery(':animated').length === 0)) &&
+          (typeof Drupal === 'undefined' || typeof Drupal.ajax === 'undefined' || !Drupal.ajax.instances.some(isAjaxing))
+        );
+      }());
+JS;
+    $script = <<<JS
+      (function() {
+        var active_instances = Drupal.ajax.instances.filter(function(instance) {
+            return instance && instance.ajaxing === true;
+        });
+        return active_instances.reduce(function(carry, item) {
+            return carry + '|||' + item.method + '-----' + item.wrapper;
+        }, '');
+      }());
+JS;
+    $result = $this->getSession()->wait(10000, $condition);
+    if (!$result) {
+      $trace = $this->getSession()->evaluateScript($script);
+      $this->htmlOutput();
+      $filename = $this->htmlOutputDirectory . '/' . $this->htmlOutputClassName . '-' . $this->htmlOutputCounter . '-UNFINISHED-FLAWED.jpg';
+      $this->createScreenshot($filename);
+      throw new \RuntimeException('FLAWED VIOLATION ' . $trace);
+    }
+    $assert_session->assertWaitOnAjaxRequest();
+  }
+
 }