diff --git a/core/modules/datetime/src/Tests/DateTestBase.php b/core/modules/datetime/src/Tests/DateTestBase.php
index 81e7550..a234ae0 100644
--- a/core/modules/datetime/src/Tests/DateTestBase.php
+++ b/core/modules/datetime/src/Tests/DateTestBase.php
@@ -2,6 +2,8 @@
 
 namespace Drupal\datetime\Tests;
 
+@trigger_error('\Drupal\datetime\Tests\DateTestBase is deprecated in Drupal 8.4.0 and will be removed before Drupal 9.0.0. Use \Drupal\Tests\BrowserTestBase instead. See https://www.drupal.org/node/2780063.', E_USER_DEPRECATED);
+
 use Drupal\Component\Utility\Unicode;
 use Drupal\Core\Entity\Entity\EntityFormDisplay;
 use Drupal\Core\Entity\Entity\EntityViewDisplay;
@@ -13,6 +15,9 @@
 
 /**
  * Provides a base class for testing Datetime field functionality.
+ *
+ * @deprecated in Drupal 8.4.0 and will be removed before Drupal 9.0.0.
+ *   Use \Drupal\Tests\BrowserTestBase instead.
  */
 abstract class DateTestBase extends WebTestBase {
 
diff --git a/core/modules/datetime/src/Tests/DateTestBase.php b/core/modules/datetime/tests/src/Functional/DateTestBase.php
similarity index 94%
copy from core/modules/datetime/src/Tests/DateTestBase.php
copy to core/modules/datetime/tests/src/Functional/DateTestBase.php
index 81e7550..369e793 100644
--- a/core/modules/datetime/src/Tests/DateTestBase.php
+++ b/core/modules/datetime/tests/src/Functional/DateTestBase.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Drupal\datetime\Tests;
+namespace Drupal\Tests\datetime\Functional;
 
 use Drupal\Component\Utility\Unicode;
 use Drupal\Core\Entity\Entity\EntityFormDisplay;
@@ -9,12 +9,12 @@
 use Drupal\entity_test\Entity\EntityTest;
 use Drupal\field\Entity\FieldConfig;
 use Drupal\field\Entity\FieldStorageConfig;
-use Drupal\simpletest\WebTestBase;
+use Drupal\Tests\BrowserTestBase;
 
 /**
  * Provides a base class for testing Datetime field functionality.
  */
-abstract class DateTestBase extends WebTestBase {
+abstract class DateTestBase extends BrowserTestBase {
 
   /**
    * Modules to enable.
@@ -153,6 +153,9 @@ protected function createField() {
    * @param bool $reset
    *   (optional) Whether to reset the entity_test controller cache. Defaults to
    *   TRUE to simplify testing.
+   *
+   * @return string
+   *   The rendered HTML output.
    */
   protected function renderTestEntity($id, $view_mode = 'full', $reset = TRUE) {
     if ($reset) {
@@ -161,9 +164,7 @@ protected function renderTestEntity($id, $view_mode = 'full', $reset = TRUE) {
     $entity = EntityTest::load($id);
     $display = EntityViewDisplay::collectRenderDisplay($entity, $view_mode);
     $build = $display->build($entity);
-    $output = $this->container->get('renderer')->renderRoot($build);
-    $this->setRawContent($output);
-    $this->verbose($output);
+    return (string) $this->container->get('renderer')->renderRoot($build);
   }
 
   /**
diff --git a/core/modules/datetime/src/Tests/DateTimeFieldTest.php b/core/modules/datetime/tests/src/Functional/DateTimeFieldTest.php
similarity index 90%
rename from core/modules/datetime/src/Tests/DateTimeFieldTest.php
rename to core/modules/datetime/tests/src/Functional/DateTimeFieldTest.php
index 827c811..ab03ff5 100644
--- a/core/modules/datetime/src/Tests/DateTimeFieldTest.php
+++ b/core/modules/datetime/tests/src/Functional/DateTimeFieldTest.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Drupal\datetime\Tests;
+namespace Drupal\Tests\datetime\Functional;
 
 use Drupal\Component\Render\FormattableMarkup;
 use Drupal\Component\Utility\SafeMarkup;
@@ -67,7 +67,7 @@ public function testDateField() {
         "{$field_name}[0][value][date]" => $date->format($date_format),
       ];
       $this->drupalPostForm(NULL, $edit, t('Save'));
-      preg_match('|entity_test/manage/(\d+)|', $this->url, $match);
+      preg_match('|entity_test/manage/(\d+)|', $this->getUrl(), $match);
       $id = $match[1];
       $this->assertText(t('entity_test @id has been created.', ['@id' => $id]));
       $this->assertRaw($date->format($date_format));
@@ -115,8 +115,9 @@ public function testDateField() {
               // field, it is expected to display the time as 00:00:00.
               $expected = format_date($date->getTimestamp(), $new_value, '', DATETIME_STORAGE_TIMEZONE);
               $expected_iso = format_date($date->getTimestamp(), 'custom', 'Y-m-d\TH:i:s\Z', DATETIME_STORAGE_TIMEZONE);
-              $this->renderTestEntity($id);
-              $this->assertFieldByXPath('//time[@datetime="' . $expected_iso . '"]', $expected, SafeMarkup::format('Formatted date field using %value format displayed as %expected with %expected_iso attribute.', ['%value' => $new_value, '%expected' => $expected, '%expected_iso' => $expected_iso]));
+              $output = $this->renderTestEntity($id);
+              $expected_markup = '<time datetime="' . $expected_iso . '" class="datetime">' . $expected . '</time>';
+              $this->assertContains($expected_markup, $output, SafeMarkup::format('Formatted date field using %value format displayed as %expected with %expected_iso attribute.', ['%value' => $new_value, '%expected' => $expected, '%expected_iso' => $expected_iso]));
               break;
           }
         }
@@ -129,8 +130,8 @@ public function testDateField() {
         ->setComponent($field_name, $this->displayOptions)
         ->save();
       $expected = $date->format(DATETIME_DATE_STORAGE_FORMAT);
-      $this->renderTestEntity($id);
-      $this->assertText($expected, SafeMarkup::format('Formatted date field using plain format displayed as %expected.', ['%expected' => $expected]));
+      $output = $this->renderTestEntity($id);
+      $this->assertContains($expected, $output, SafeMarkup::format('Formatted date field using plain format displayed as %expected.', ['%expected' => $expected]));
 
       // Verify that the 'datetime_custom' formatter works.
       $this->displayOptions['type'] = 'datetime_custom';
@@ -139,8 +140,8 @@ public function testDateField() {
         ->setComponent($field_name, $this->displayOptions)
         ->save();
       $expected = $date->format($this->displayOptions['settings']['date_format']);
-      $this->renderTestEntity($id);
-      $this->assertText($expected, SafeMarkup::format('Formatted date field using datetime_custom format displayed as %expected.', ['%expected' => $expected]));
+      $output = $this->renderTestEntity($id);
+      $this->assertContains($expected, $output, SafeMarkup::format('Formatted date field using datetime_custom format displayed as %expected.', ['%expected' => $expected]));
 
       // Test that allowed markup in custom format is preserved and XSS is
       // removed.
@@ -149,8 +150,8 @@ public function testDateField() {
         ->setComponent($field_name, $this->displayOptions)
         ->save();
       $expected = '<strong>' . $date->format('m/d/Y') . '</strong>alert(String.fromCharCode(88,83,83))';
-      $this->renderTestEntity($id);
-      $this->assertRaw($expected, new FormattableMarkup('Formatted date field using daterange_custom format displayed as %expected.', ['%expected' => $expected]));
+      $output = $this->renderTestEntity($id);
+      $this->assertContains($expected, $output, new FormattableMarkup('Formatted date field using daterange_custom format displayed as %expected.', ['%expected' => $expected]));
 
       // Verify that the 'datetime_time_ago' formatter works for intervals in the
       // past.  First update the test entity so that the date difference always
@@ -176,8 +177,8 @@ public function testDateField() {
       $expected = SafeMarkup::format($this->displayOptions['settings']['past_format'], [
         '@interval' => $this->dateFormatter->formatTimeDiffSince($timestamp, ['granularity' => $this->displayOptions['settings']['granularity']])
       ]);
-      $this->renderTestEntity($id);
-      $this->assertText($expected, SafeMarkup::format('Formatted date field using datetime_time_ago format displayed as %expected.', ['%expected' => $expected]));
+      $output = $this->renderTestEntity($id);
+      $this->assertContains((string) $expected, $output, SafeMarkup::format('Formatted date field using datetime_time_ago format displayed as %expected.', ['%expected' => $expected]));
 
       // Verify that the 'datetime_time_ago' formatter works for intervals in the
       // future.  First update the test entity so that the date difference always
@@ -197,8 +198,8 @@ public function testDateField() {
       $expected = SafeMarkup::format($this->displayOptions['settings']['future_format'], [
         '@interval' => $this->dateFormatter->formatTimeDiffUntil($timestamp, ['granularity' => $this->displayOptions['settings']['granularity']])
       ]);
-      $this->renderTestEntity($id);
-      $this->assertText($expected, SafeMarkup::format('Formatted date field using datetime_time_ago format displayed as %expected.', ['%expected' => $expected]));
+      $output = $this->renderTestEntity($id);
+      $this->assertContains((string) $expected, $output, SafeMarkup::format('Formatted date field using datetime_time_ago format displayed as %expected.', ['%expected' => $expected]));
     }
   }
 
@@ -215,7 +216,7 @@ public function testDatetimeField() {
     $this->drupalGet('entity_test/add');
     $this->assertFieldByName("{$field_name}[0][value][date]", '', 'Date element found.');
     $this->assertFieldByName("{$field_name}[0][value][time]", '', 'Time element found.');
-    $this->assertFieldByXPath('//fieldset[@id="edit-' . $field_name . '-0"]/legend//text()', $field_name, 'Fieldset and label found');
+    $this->assertFieldByXPath('//fieldset[@id="edit-' . $field_name . '-0"]/legend', $field_name, 'Fieldset and label found');
     $this->assertFieldByXPath('//fieldset[@aria-describedby="edit-' . $field_name . '-0--description"]', NULL, 'ARIA described-by found');
     $this->assertFieldByXPath('//div[@id="edit-' . $field_name . '-0--description"]', NULL, 'ARIA description found');
 
@@ -235,7 +236,7 @@ public function testDatetimeField() {
       "{$field_name}[0][value][time]" => $date->format($time_format),
     ];
     $this->drupalPostForm(NULL, $edit, t('Save'));
-    preg_match('|entity_test/manage/(\d+)|', $this->url, $match);
+    preg_match('|entity_test/manage/(\d+)|', $this->getUrl(), $match);
     $id = $match[1];
     $this->assertText(t('entity_test @id has been created.', ['@id' => $id]));
     $this->assertRaw($date->format($date_format));
@@ -259,8 +260,9 @@ public function testDatetimeField() {
             // Verify that a date is displayed.
             $expected = format_date($date->getTimestamp(), $new_value);
             $expected_iso = format_date($date->getTimestamp(), 'custom', 'Y-m-d\TH:i:s\Z', 'UTC');
-            $this->renderTestEntity($id);
-            $this->assertFieldByXPath('//time[@datetime="' . $expected_iso . '"]', $expected, SafeMarkup::format('Formatted date field using %value format displayed as %expected with %expected_iso attribute.', ['%value' => $new_value, '%expected' => $expected, '%expected_iso' => $expected_iso]));
+            $output = $this->renderTestEntity($id);
+            $expected_markup = '<time datetime="' . $expected_iso . '" class="datetime">' . $expected . '</time>';
+            $this->assertContains($expected_markup, $output, SafeMarkup::format('Formatted date field using %value format displayed as %expected with %expected_iso attribute.', ['%value' => $new_value, '%expected' => $expected, '%expected_iso' => $expected_iso]));
             break;
         }
       }
@@ -273,8 +275,8 @@ public function testDatetimeField() {
       ->setComponent($field_name, $this->displayOptions)
       ->save();
     $expected = $date->format(DATETIME_DATETIME_STORAGE_FORMAT);
-    $this->renderTestEntity($id);
-    $this->assertText($expected, SafeMarkup::format('Formatted date field using plain format displayed as %expected.', ['%expected' => $expected]));
+    $output = $this->renderTestEntity($id);
+    $this->assertContains($expected, $output, SafeMarkup::format('Formatted date field using plain format displayed as %expected.', ['%expected' => $expected]));
 
     // Verify that the 'datetime_custom' formatter works.
     $this->displayOptions['type'] = 'datetime_custom';
@@ -283,8 +285,8 @@ public function testDatetimeField() {
       ->setComponent($field_name, $this->displayOptions)
       ->save();
     $expected = $date->format($this->displayOptions['settings']['date_format']);
-    $this->renderTestEntity($id);
-    $this->assertText($expected, SafeMarkup::format('Formatted date field using datetime_custom format displayed as %expected.', ['%expected' => $expected]));
+    $output = $this->renderTestEntity($id);
+    $this->assertContains($expected, $output, SafeMarkup::format('Formatted date field using datetime_custom format displayed as %expected.', ['%expected' => $expected]));
 
     // Verify that the 'timezone_override' setting works.
     $this->displayOptions['type'] = 'datetime_custom';
@@ -293,8 +295,8 @@ public function testDatetimeField() {
       ->setComponent($field_name, $this->displayOptions)
       ->save();
     $expected = $date->format($this->displayOptions['settings']['date_format'], ['timezone' => 'America/New_York']);
-    $this->renderTestEntity($id);
-    $this->assertText($expected, SafeMarkup::format('Formatted date field using datetime_custom format displayed as %expected.', ['%expected' => $expected]));
+    $output = $this->renderTestEntity($id);
+    $this->assertContains($expected, $output, SafeMarkup::format('Formatted date field using datetime_custom format displayed as %expected.', ['%expected' => $expected]));
 
     // Verify that the 'datetime_time_ago' formatter works for intervals in the
     // past.  First update the test entity so that the date difference always
@@ -320,8 +322,8 @@ public function testDatetimeField() {
     $expected = SafeMarkup::format($this->displayOptions['settings']['past_format'], [
       '@interval' => $this->dateFormatter->formatTimeDiffSince($timestamp, ['granularity' => $this->displayOptions['settings']['granularity']])
     ]);
-    $this->renderTestEntity($id);
-    $this->assertText($expected, SafeMarkup::format('Formatted date field using datetime_time_ago format displayed as %expected.', ['%expected' => $expected]));
+    $output = $this->renderTestEntity($id);
+    $this->assertContains((string) $expected, $output, SafeMarkup::format('Formatted date field using datetime_time_ago format displayed as %expected.', ['%expected' => $expected]));
 
     // Verify that the 'datetime_time_ago' formatter works for intervals in the
     // future.  First update the test entity so that the date difference always
@@ -341,8 +343,8 @@ public function testDatetimeField() {
     $expected = SafeMarkup::format($this->displayOptions['settings']['future_format'], [
       '@interval' => $this->dateFormatter->formatTimeDiffUntil($timestamp, ['granularity' => $this->displayOptions['settings']['granularity']])
     ]);
-    $this->renderTestEntity($id);
-    $this->assertText($expected, SafeMarkup::format('Formatted date field using datetime_time_ago format displayed as %expected.', ['%expected' => $expected]));
+    $output = $this->renderTestEntity($id);
+    $this->assertContains((string) $expected, $output, SafeMarkup::format('Formatted date field using datetime_time_ago format displayed as %expected.', ['%expected' => $expected]));
   }
 
   /**
@@ -368,7 +370,7 @@ public function testDatelistWidget() {
 
     // Display creation form.
     $this->drupalGet('entity_test/add');
-    $this->assertFieldByXPath('//fieldset[@id="edit-' . $field_name . '-0"]/legend//text()', $field_name, 'Fieldset and label found');
+    $this->assertFieldByXPath('//fieldset[@id="edit-' . $field_name . '-0"]/legend', $field_name, 'Fieldset and label found');
     $this->assertFieldByXPath('//fieldset[@aria-describedby="edit-' . $field_name . '-0--description"]', NULL, 'ARIA described-by found');
     $this->assertFieldByXPath('//div[@id="edit-' . $field_name . '-0--description"]', NULL, 'ARIA description found');
 
@@ -381,7 +383,7 @@ public function testDatelistWidget() {
     $this->drupalGet($fieldEditUrl);
 
     // Click on the widget settings button to open the widget settings form.
-    $this->drupalPostAjaxForm(NULL, [], $field_name . "_settings_edit");
+    $this->drupalPostForm(NULL, [], $field_name . "_settings_edit");
     $xpathIncr = "//select[starts-with(@id, \"edit-fields-$field_name-settings-edit-form-settings-increment\")]";
     $this->assertNoFieldByXPath($xpathIncr, NULL, 'Increment element not found for Date Only.');
 
@@ -407,7 +409,7 @@ public function testDatelistWidget() {
     $this->drupalGet($fieldEditUrl);
 
     // Click on the widget settings button to open the widget settings form.
-    $this->drupalPostAjaxForm(NULL, [], $field_name . "_settings_edit");
+    $this->drupalPostForm(NULL, [], $field_name . "_settings_edit");
     $this->assertFieldByXPath($xpathIncr, NULL, 'Increment element found for Date and time.');
 
     // Display creation form.
@@ -444,7 +446,7 @@ public function testDatelistWidget() {
     }
 
     $this->drupalPostForm(NULL, $edit, t('Save'));
-    preg_match('|entity_test/manage/(\d+)|', $this->url, $match);
+    preg_match('|entity_test/manage/(\d+)|', $this->getUrl(), $match);
     $id = $match[1];
     $this->assertText(t('entity_test @id has been created.', ['@id' => $id]));
 
@@ -485,7 +487,7 @@ public function testDatelistWidget() {
     }
 
     $this->drupalPostForm(NULL, $edit, t('Save'));
-    preg_match('|entity_test/manage/(\d+)|', $this->url, $match);
+    preg_match('|entity_test/manage/(\d+)|', $this->getUrl(), $match);
     $id = $match[1];
     $this->assertText(t('entity_test @id has been created.', ['@id' => $id]));
 
@@ -539,7 +541,7 @@ public function testDatelistWidget() {
 
     $this->drupalPostForm(NULL, $edit, t('Save'));
     $this->assertResponse(200);
-    preg_match('|entity_test/manage/(\d+)|', $this->url, $match);
+    preg_match('|entity_test/manage/(\d+)|', $this->getUrl(), $match);
     $id = $match[1];
     $this->assertText(t('entity_test @id has been created.', ['@id' => $id]));
 
diff --git a/core/modules/datetime_range/src/Tests/DateRangeFieldTest.php b/core/modules/datetime_range/tests/src/Functional/DateRangeFieldTest.php
similarity index 87%
rename from core/modules/datetime_range/src/Tests/DateRangeFieldTest.php
rename to core/modules/datetime_range/tests/src/Functional/DateRangeFieldTest.php
index f553315..23ba8fa 100644
--- a/core/modules/datetime_range/src/Tests/DateRangeFieldTest.php
+++ b/core/modules/datetime_range/tests/src/Functional/DateRangeFieldTest.php
@@ -1,12 +1,12 @@
 <?php
 
-namespace Drupal\datetime_range\Tests;
+namespace Drupal\Tests\datetime_range\Functional;
 
 use Drupal\Component\Render\FormattableMarkup;
 use Drupal\Component\Utility\Unicode;
 use Drupal\Core\Datetime\DrupalDateTime;
 use Drupal\Core\Datetime\Entity\DateFormat;
-use Drupal\datetime\Tests\DateTestBase;
+use Drupal\Tests\datetime\Functional\DateTestBase;
 use Drupal\datetime_range\Plugin\Field\FieldType\DateRangeItem;
 use Drupal\entity_test\Entity\EntityTest;
 use Drupal\field\Entity\FieldConfig;
@@ -64,7 +64,7 @@ public function testDateRangeField() {
       $this->assertFieldByXPath('//*[@id="edit-' . $field_name . '-wrapper"]//label[contains(@class, "js-form-required")]', TRUE, 'Required markup found');
       $this->assertNoFieldByName("{$field_name}[0][value][time]", '', 'Start time element not found.');
       $this->assertNoFieldByName("{$field_name}[0][end_value][time]", '', 'End time element not found.');
-      $this->assertFieldByXPath('//fieldset[@id="edit-' . $field_name . '-0"]/legend//text()', $field_name, 'Fieldset and label found');
+      $this->assertFieldByXPath('//fieldset[@id="edit-' . $field_name . '-0"]/legend', $field_name, 'Fieldset and label found');
       $this->assertFieldByXPath('//fieldset[@aria-describedby="edit-' . $field_name . '-0--description"]', NULL, 'ARIA described-by found');
       $this->assertFieldByXPath('//div[@id="edit-' . $field_name . '-0--description"]', NULL, 'ARIA description found');
 
@@ -83,7 +83,7 @@ public function testDateRangeField() {
         "{$field_name}[0][end_value][date]" => $end_date->format($date_format),
       ];
       $this->drupalPostForm(NULL, $edit, t('Save'));
-      preg_match('|entity_test/manage/(\d+)|', $this->url, $match);
+      preg_match('|entity_test/manage/(\d+)|', $this->getUrl(), $match);
       $id = $match[1];
       $this->assertText(t('entity_test @id has been created.', ['@id' => $id]));
       $this->assertRaw($start_date->format($date_format));
@@ -128,20 +128,22 @@ public function testDateRangeField() {
 
       $start_expected = $this->dateFormatter->format($start_date->getTimestamp(), 'long', '', DATETIME_STORAGE_TIMEZONE);
       $start_expected_iso = $this->dateFormatter->format($start_date->getTimestamp(), 'custom', 'Y-m-d\TH:i:s\Z', DATETIME_STORAGE_TIMEZONE);
+      $start_expected_markup = '<time datetime="' . $start_expected_iso . '" class="datetime">' . $start_expected . '</time>';
       $end_expected = $this->dateFormatter->format($end_date->getTimestamp(), 'long', '', DATETIME_STORAGE_TIMEZONE);
       $end_expected_iso = $this->dateFormatter->format($end_date->getTimestamp(), 'custom', 'Y-m-d\TH:i:s\Z', DATETIME_STORAGE_TIMEZONE);
-      $this->renderTestEntity($id);
-      $this->assertFieldByXPath('//time[@datetime="' . $start_expected_iso . '"]', $start_expected, new FormattableMarkup('Formatted date field using %value format displayed as %expected with %expected_iso attribute.', [
+      $end_expected_markup = '<time datetime="' . $end_expected_iso . '" class="datetime">' . $end_expected . '</time>';
+      $output = $this->renderTestEntity($id);
+      $this->assertContains($start_expected_markup, $output, new FormattableMarkup('Formatted date field using %value format displayed as %expected with %expected_iso attribute.', [
         '%value' => 'long',
         '%expected' => $start_expected,
         '%expected_iso' => $start_expected_iso,
       ]));
-      $this->assertFieldByXPath('//time[@datetime="' . $end_expected_iso . '"]', $end_expected, new FormattableMarkup('Formatted date field using %value format displayed as %expected with %expected_iso attribute.', [
+      $this->assertContains($end_expected_markup, $output, new FormattableMarkup('Formatted date field using %value format displayed as %expected with %expected_iso attribute.', [
         '%value' => 'long',
         '%expected' => $end_expected,
         '%expected_iso' => $end_expected_iso,
       ]));
-      $this->assertText(' THESEPARATOR ', 'Found proper separator');
+      $this->assertContains(' THESEPARATOR ', $output, 'Found proper separator');
 
       // Verify that hook_entity_prepare_view can add attributes.
       // @see entity_test_entity_prepare_view()
@@ -155,8 +157,8 @@ public function testDateRangeField() {
         ->setComponent($field_name, $this->displayOptions)
         ->save();
       $expected = $start_date->format(DATETIME_DATE_STORAGE_FORMAT) . ' - ' . $end_date->format(DATETIME_DATE_STORAGE_FORMAT);
-      $this->renderTestEntity($id);
-      $this->assertText($expected, new FormattableMarkup('Formatted date field using plain format displayed as %expected.', ['%expected' => $expected]));
+      $output = $this->renderTestEntity($id);
+      $this->assertContains($expected, $output, new FormattableMarkup('Formatted date field using plain format displayed as %expected.', ['%expected' => $expected]));
 
       // Verify that the custom formatter works.
       $this->displayOptions['type'] = 'daterange_custom';
@@ -165,8 +167,8 @@ public function testDateRangeField() {
         ->setComponent($field_name, $this->displayOptions)
         ->save();
       $expected = $start_date->format($this->displayOptions['settings']['date_format']) . ' - ' . $end_date->format($this->displayOptions['settings']['date_format']);
-      $this->renderTestEntity($id);
-      $this->assertText($expected, new FormattableMarkup('Formatted date field using daterange_custom format displayed as %expected.', ['%expected' => $expected]));
+      $output = $this->renderTestEntity($id);
+      $this->assertContains($expected, $output, new FormattableMarkup('Formatted date field using daterange_custom format displayed as %expected.', ['%expected' => $expected]));
 
       // Test that allowed markup in custom format is preserved and XSS is
       // removed.
@@ -175,8 +177,8 @@ public function testDateRangeField() {
         ->setComponent($field_name, $this->displayOptions)
         ->save();
       $expected = '<strong>' . $start_date->format('m/d/Y') . '</strong>alert(String.fromCharCode(88,83,83)) - <strong>' . $end_date->format('m/d/Y') . '</strong>alert(String.fromCharCode(88,83,83))';
-      $this->renderTestEntity($id);
-      $this->assertRaw($expected, new FormattableMarkup('Formatted date field using daterange_custom format displayed as %expected.', ['%expected' => $expected]));
+      $output = $this->renderTestEntity($id);
+      $this->assertContains($expected, $output, new FormattableMarkup('Formatted date field using daterange_custom format displayed as %expected.', ['%expected' => $expected]));
 
       // Test formatters when start date and end date are the same
       $this->drupalGet('entity_test/add');
@@ -192,7 +194,7 @@ public function testDateRangeField() {
       ];
 
       $this->drupalPostForm(NULL, $edit, t('Save'));
-      preg_match('|entity_test/manage/(\d+)|', $this->url, $match);
+      preg_match('|entity_test/manage/(\d+)|', $this->getUrl(), $match);
       $id = $match[1];
       $this->assertText(t('entity_test @id has been created.', ['@id' => $id]));
 
@@ -213,13 +215,14 @@ public function testDateRangeField() {
 
       $start_expected = $this->dateFormatter->format($start_date->getTimestamp(), 'long', '', DATETIME_STORAGE_TIMEZONE);
       $start_expected_iso = $this->dateFormatter->format($start_date->getTimestamp(), 'custom', 'Y-m-d\TH:i:s\Z', DATETIME_STORAGE_TIMEZONE);
-      $this->renderTestEntity($id);
-      $this->assertFieldByXPath('//time[@datetime="' . $start_expected_iso . '"]', $start_expected, new FormattableMarkup('Formatted date field using %value format displayed as %expected with %expected_iso attribute.', [
+      $start_expected_markup = '<time datetime="' . $start_expected_iso . '" class="datetime">' . $start_expected . '</time>';
+      $output = $this->renderTestEntity($id);
+      $this->assertContains($start_expected_markup, $output, new FormattableMarkup('Formatted date field using %value format displayed as %expected with %expected_iso attribute.', [
         '%value' => 'long',
         '%expected' => $start_expected,
         '%expected_iso' => $start_expected_iso,
       ]));
-      $this->assertNoText(' THESEPARATOR ', 'Separator not found on page');
+      $this->assertNotContains(' THESEPARATOR ', $output, 'Separator not found on page');
 
       // Verify that hook_entity_prepare_view can add attributes.
       // @see entity_test_entity_prepare_view()
@@ -232,9 +235,9 @@ public function testDateRangeField() {
         ->setComponent($field_name, $this->displayOptions)
         ->save();
       $expected = $start_date->format(DATETIME_DATE_STORAGE_FORMAT);
-      $this->renderTestEntity($id);
-      $this->assertText($expected, new FormattableMarkup('Formatted date field using plain format displayed as %expected.', ['%expected' => $expected]));
-      $this->assertNoText(' THESEPARATOR ', 'Separator not found on page');
+      $output = $this->renderTestEntity($id);
+      $this->assertContains($expected, $output, new FormattableMarkup('Formatted date field using plain format displayed as %expected.', ['%expected' => $expected]));
+      $this->assertNotContains(' THESEPARATOR ', $output, 'Separator not found on page');
 
       $this->displayOptions['type'] = 'daterange_custom';
       $this->displayOptions['settings'] = ['date_format' => 'm/d/Y'] + $this->defaultSettings;
@@ -242,9 +245,9 @@ public function testDateRangeField() {
         ->setComponent($field_name, $this->displayOptions)
         ->save();
       $expected = $start_date->format($this->displayOptions['settings']['date_format']);
-      $this->renderTestEntity($id);
-      $this->assertText($expected, new FormattableMarkup('Formatted date field using daterange_custom format displayed as %expected.', ['%expected' => $expected]));
-      $this->assertNoText(' THESEPARATOR ', 'Separator not found on page');
+      $output = $this->renderTestEntity($id);
+      $this->assertContains($expected, $output, new FormattableMarkup('Formatted date field using daterange_custom format displayed as %expected.', ['%expected' => $expected]));
+      $this->assertNotContains(' THESEPARATOR ', $output, 'Separator not found on page');
     }
   }
 
@@ -264,7 +267,7 @@ public function testDatetimeRangeField() {
     $this->assertFieldByName("{$field_name}[0][value][time]", '', 'Start time element found.');
     $this->assertFieldByName("{$field_name}[0][end_value][date]", '', 'End date element found.');
     $this->assertFieldByName("{$field_name}[0][end_value][time]", '', 'End time element found.');
-    $this->assertFieldByXPath('//fieldset[@id="edit-' . $field_name . '-0"]/legend//text()', $field_name, 'Fieldset and label found');
+    $this->assertFieldByXPath('//fieldset[@id="edit-' . $field_name . '-0"]/legend', $field_name, 'Fieldset and label found');
     $this->assertFieldByXPath('//fieldset[@aria-describedby="edit-' . $field_name . '-0--description"]', NULL, 'ARIA described-by found');
     $this->assertFieldByXPath('//div[@id="edit-' . $field_name . '-0--description"]', NULL, 'ARIA description found');
 
@@ -289,7 +292,7 @@ public function testDatetimeRangeField() {
       "{$field_name}[0][end_value][time]" => $end_date->format($time_format),
     ];
     $this->drupalPostForm(NULL, $edit, t('Save'));
-    preg_match('|entity_test/manage/(\d+)|', $this->url, $match);
+    preg_match('|entity_test/manage/(\d+)|', $this->getUrl(), $match);
     $id = $match[1];
     $this->assertText(t('entity_test @id has been created.', ['@id' => $id]));
     $this->assertRaw($start_date->format($date_format));
@@ -308,12 +311,14 @@ public function testDatetimeRangeField() {
 
     $start_expected = $this->dateFormatter->format($start_date->getTimestamp(), 'long');
     $start_expected_iso = $this->dateFormatter->format($start_date->getTimestamp(), 'custom', 'Y-m-d\TH:i:s\Z', 'UTC');
+    $start_expected_markup = '<time datetime="' . $start_expected_iso . '" class="datetime">' . $start_expected . '</time>';
     $end_expected = $this->dateFormatter->format($end_date->getTimestamp(), 'long');
     $end_expected_iso = $this->dateFormatter->format($end_date->getTimestamp(), 'custom', 'Y-m-d\TH:i:s\Z', 'UTC');
-    $this->renderTestEntity($id);
-    $this->assertFieldByXPath('//time[@datetime="' . $start_expected_iso . '"]', $start_expected, new FormattableMarkup('Formatted date field using %value format displayed as %expected with %expected_iso attribute.', ['%value' => 'long', '%expected' => $start_expected, '%expected_iso' => $start_expected_iso]));
-    $this->assertFieldByXPath('//time[@datetime="' . $end_expected_iso . '"]', $end_expected, new FormattableMarkup('Formatted date field using %value format displayed as %expected with %expected_iso attribute.', ['%value' => 'long', '%expected' => $end_expected, '%expected_iso' => $end_expected_iso]));
-    $this->assertText(' THESEPARATOR ', 'Found proper separator');
+    $end_expected_markup = '<time datetime="' . $end_expected_iso . '" class="datetime">' . $end_expected . '</time>';
+    $output = $this->renderTestEntity($id);
+    $this->assertContains($start_expected_markup, $output, new FormattableMarkup('Formatted date field using %value format displayed as %expected with %expected_iso attribute.', ['%value' => 'long', '%expected' => $start_expected, '%expected_iso' => $start_expected_iso]));
+    $this->assertContains($end_expected_markup, $output, new FormattableMarkup('Formatted date field using %value format displayed as %expected with %expected_iso attribute.', ['%value' => 'long', '%expected' => $end_expected, '%expected_iso' => $end_expected_iso]));
+    $this->assertContains(' THESEPARATOR ', $output, 'Found proper separator');
 
     // Verify that hook_entity_prepare_view can add attributes.
     // @see entity_test_entity_prepare_view()
@@ -327,8 +332,8 @@ public function testDatetimeRangeField() {
       ->setComponent($field_name, $this->displayOptions)
       ->save();
     $expected = $start_date->format(DATETIME_DATETIME_STORAGE_FORMAT) . ' - ' . $end_date->format(DATETIME_DATETIME_STORAGE_FORMAT);
-    $this->renderTestEntity($id);
-    $this->assertText($expected, new FormattableMarkup('Formatted date field using plain format displayed as %expected.', ['%expected' => $expected]));
+    $output = $this->renderTestEntity($id);
+    $this->assertContains($expected, $output, new FormattableMarkup('Formatted date field using plain format displayed as %expected.', ['%expected' => $expected]));
 
     // Verify that the 'datetime_custom' formatter works.
     $this->displayOptions['type'] = 'daterange_custom';
@@ -337,8 +342,8 @@ public function testDatetimeRangeField() {
       ->setComponent($field_name, $this->displayOptions)
       ->save();
     $expected = $start_date->format($this->displayOptions['settings']['date_format']) . ' - ' . $end_date->format($this->displayOptions['settings']['date_format']);
-    $this->renderTestEntity($id);
-    $this->assertText($expected, new FormattableMarkup('Formatted date field using daterange_custom format displayed as %expected.', ['%expected' => $expected]));
+    $output = $this->renderTestEntity($id);
+    $this->assertContains($expected, $output, new FormattableMarkup('Formatted date field using daterange_custom format displayed as %expected.', ['%expected' => $expected]));
 
     // Verify that the 'timezone_override' setting works.
     $this->displayOptions['type'] = 'daterange_custom';
@@ -348,8 +353,8 @@ public function testDatetimeRangeField() {
       ->save();
     $expected = $start_date->format($this->displayOptions['settings']['date_format'], ['timezone' => 'America/New_York']);
     $expected .= ' - ' . $end_date->format($this->displayOptions['settings']['date_format'], ['timezone' => 'America/New_York']);
-    $this->renderTestEntity($id);
-    $this->assertText($expected, new FormattableMarkup('Formatted date field using daterange_custom format displayed as %expected.', ['%expected' => $expected]));
+    $output = $this->renderTestEntity($id);
+    $this->assertContains($expected, $output, new FormattableMarkup('Formatted date field using daterange_custom format displayed as %expected.', ['%expected' => $expected]));
 
     // Test formatters when start date and end date are the same
     $this->drupalGet('entity_test/add');
@@ -368,7 +373,7 @@ public function testDatetimeRangeField() {
     ];
 
     $this->drupalPostForm(NULL, $edit, t('Save'));
-    preg_match('|entity_test/manage/(\d+)|', $this->url, $match);
+    preg_match('|entity_test/manage/(\d+)|', $this->getUrl(), $match);
     $id = $match[1];
     $this->assertText(t('entity_test @id has been created.', ['@id' => $id]));
 
@@ -387,9 +392,10 @@ public function testDatetimeRangeField() {
 
     $start_expected = $this->dateFormatter->format($start_date->getTimestamp(), 'long');
     $start_expected_iso = $this->dateFormatter->format($start_date->getTimestamp(), 'custom', 'Y-m-d\TH:i:s\Z', 'UTC');
-    $this->renderTestEntity($id);
-    $this->assertFieldByXPath('//time[@datetime="' . $start_expected_iso . '"]', $start_expected, new FormattableMarkup('Formatted date field using %value format displayed as %expected with %expected_iso attribute.', ['%value' => 'long', '%expected' => $start_expected, '%expected_iso' => $start_expected_iso]));
-    $this->assertNoText(' THESEPARATOR ', 'Separator not found on page');
+    $start_expected_markup = '<time datetime="' . $start_expected_iso . '" class="datetime">' . $start_expected . '</time>';
+    $output = $this->renderTestEntity($id);
+    $this->assertContains($start_expected_markup, $output, new FormattableMarkup('Formatted date field using %value format displayed as %expected with %expected_iso attribute.', ['%value' => 'long', '%expected' => $start_expected, '%expected_iso' => $start_expected_iso]));
+    $this->assertNotContains(' THESEPARATOR ', $output, 'Separator not found on page');
 
     // Verify that hook_entity_prepare_view can add attributes.
     // @see entity_test_entity_prepare_view()
@@ -402,9 +408,9 @@ public function testDatetimeRangeField() {
       ->setComponent($field_name, $this->displayOptions)
       ->save();
     $expected = $start_date->format(DATETIME_DATETIME_STORAGE_FORMAT);
-    $this->renderTestEntity($id);
-    $this->assertText($expected, new FormattableMarkup('Formatted date field using plain format displayed as %expected.', ['%expected' => $expected]));
-    $this->assertNoText(' THESEPARATOR ', 'Separator not found on page');
+    $output = $this->renderTestEntity($id);
+    $this->assertContains($expected, $output, new FormattableMarkup('Formatted date field using plain format displayed as %expected.', ['%expected' => $expected]));
+    $this->assertNotContains(' THESEPARATOR ', $output, 'Separator not found on page');
 
     $this->displayOptions['type'] = 'daterange_custom';
     $this->displayOptions['settings'] = ['date_format' => 'm/d/Y g:i:s A'] + $this->defaultSettings;
@@ -412,9 +418,9 @@ public function testDatetimeRangeField() {
       ->setComponent($field_name, $this->displayOptions)
       ->save();
     $expected = $start_date->format($this->displayOptions['settings']['date_format']);
-    $this->renderTestEntity($id);
-    $this->assertText($expected, new FormattableMarkup('Formatted date field using daterange_custom format displayed as %expected.', ['%expected' => $expected]));
-    $this->assertNoText(' THESEPARATOR ', 'Separator not found on page');
+    $output = $this->renderTestEntity($id);
+    $this->assertContains($expected, $output, new FormattableMarkup('Formatted date field using daterange_custom format displayed as %expected.', ['%expected' => $expected]));
+    $this->assertNotContains(' THESEPARATOR ', $output, 'Separator not found on page');
   }
 
   /**
@@ -434,7 +440,7 @@ public function testAlldayRangeField() {
     $this->assertFieldByXPath('//*[@id="edit-' . $field_name . '-wrapper"]//label[contains(@class, "js-form-required")]', TRUE, 'Required markup found');
     $this->assertNoFieldByName("{$field_name}[0][value][time]", '', 'Start time element not found.');
     $this->assertNoFieldByName("{$field_name}[0][end_value][time]", '', 'End time element not found.');
-    $this->assertFieldByXPath('//fieldset[@id="edit-' . $field_name . '-0"]/legend//text()', $field_name, 'Fieldset and label found');
+    $this->assertFieldByXPath('//fieldset[@id="edit-' . $field_name . '-0"]/legend', $field_name, 'Fieldset and label found');
     $this->assertFieldByXPath('//fieldset[@aria-describedby="edit-' . $field_name . '-0--description"]', NULL, 'ARIA described-by found');
     $this->assertFieldByXPath('//div[@id="edit-' . $field_name . '-0--description"]', NULL, 'ARIA description found');
 
@@ -453,7 +459,7 @@ public function testAlldayRangeField() {
       "{$field_name}[0][end_value][date]" => $end_date->format($date_format),
     ];
     $this->drupalPostForm(NULL, $edit, t('Save'));
-    preg_match('|entity_test/manage/(\d+)|', $this->url, $match);
+    preg_match('|entity_test/manage/(\d+)|', $this->getUrl(), $match);
     $id = $match[1];
     $this->assertText(t('entity_test @id has been created.', ['@id' => $id]));
     $this->assertRaw($start_date->format($date_format));
@@ -472,12 +478,14 @@ public function testAlldayRangeField() {
 
     $start_expected = $this->dateFormatter->format($start_date->getTimestamp(), 'long');
     $start_expected_iso = $this->dateFormatter->format($start_date->getTimestamp(), 'custom', 'Y-m-d\TH:i:s\Z', 'UTC');
+    $start_expected_markup = '<time datetime="' . $start_expected_iso . '" class="datetime">' . $start_expected . '</time>';
     $end_expected = $this->dateFormatter->format($end_date->getTimestamp(), 'long');
     $end_expected_iso = $this->dateFormatter->format($end_date->getTimestamp(), 'custom', 'Y-m-d\TH:i:s\Z', 'UTC');
-    $this->renderTestEntity($id);
-    $this->assertFieldByXPath('//time[@datetime="' . $start_expected_iso . '"]', $start_expected, new FormattableMarkup('Formatted date field using %value format displayed as %expected with %expected_iso attribute.', ['%value' => 'long', '%expected' => $start_expected, '%expected_iso' => $start_expected_iso]));
-    $this->assertFieldByXPath('//time[@datetime="' . $end_expected_iso . '"]', $end_expected, new FormattableMarkup('Formatted date field using %value format displayed as %expected with %expected_iso attribute.', ['%value' => 'long', '%expected' => $end_expected, '%expected_iso' => $end_expected_iso]));
-    $this->assertText(' THESEPARATOR ', 'Found proper separator');
+    $end_expected_markup = '<time datetime="' . $end_expected_iso . '" class="datetime">' . $end_expected . '</time>';
+    $output = $this->renderTestEntity($id);
+    $this->assertContains($start_expected_markup, $output, new FormattableMarkup('Formatted date field using %value format displayed as %expected with %expected_iso attribute.', ['%value' => 'long', '%expected' => $start_expected, '%expected_iso' => $start_expected_iso]));
+    $this->assertContains($end_expected_markup, $output, new FormattableMarkup('Formatted date field using %value format displayed as %expected with %expected_iso attribute.', ['%value' => 'long', '%expected' => $end_expected, '%expected_iso' => $end_expected_iso]));
+    $this->assertContains(' THESEPARATOR ', $output, 'Found proper separator');
 
     // Verify that hook_entity_prepare_view can add attributes.
     // @see entity_test_entity_prepare_view()
@@ -491,8 +499,8 @@ public function testAlldayRangeField() {
       ->setComponent($field_name, $this->displayOptions)
       ->save();
     $expected = $start_date->format(DATETIME_DATETIME_STORAGE_FORMAT) . ' - ' . $end_date->format(DATETIME_DATETIME_STORAGE_FORMAT);
-    $this->renderTestEntity($id);
-    $this->assertText($expected, new FormattableMarkup('Formatted date field using plain format displayed as %expected.', ['%expected' => $expected]));
+    $output = $this->renderTestEntity($id);
+    $this->assertContains($expected, $output, new FormattableMarkup('Formatted date field using plain format displayed as %expected.', ['%expected' => $expected]));
 
     // Verify that the custom formatter works.
     $this->displayOptions['type'] = 'daterange_custom';
@@ -501,8 +509,8 @@ public function testAlldayRangeField() {
       ->setComponent($field_name, $this->displayOptions)
       ->save();
     $expected = $start_date->format($this->displayOptions['settings']['date_format']) . ' - ' . $end_date->format($this->displayOptions['settings']['date_format']);
-    $this->renderTestEntity($id);
-    $this->assertText($expected, new FormattableMarkup('Formatted date field using daterange_custom format displayed as %expected.', ['%expected' => $expected]));
+    $output = $this->renderTestEntity($id);
+    $this->assertContains($expected, $output, new FormattableMarkup('Formatted date field using daterange_custom format displayed as %expected.', ['%expected' => $expected]));
 
     // Verify that the 'timezone_override' setting works.
     $this->displayOptions['type'] = 'daterange_custom';
@@ -512,8 +520,8 @@ public function testAlldayRangeField() {
       ->save();
     $expected = $start_date->format($this->displayOptions['settings']['date_format'], ['timezone' => 'America/New_York']);
     $expected .= ' - ' . $end_date->format($this->displayOptions['settings']['date_format'], ['timezone' => 'America/New_York']);
-    $this->renderTestEntity($id);
-    $this->assertText($expected, new FormattableMarkup('Formatted date field using daterange_custom format displayed as %expected.', ['%expected' => $expected]));
+    $output = $this->renderTestEntity($id);
+    $this->assertContains($expected, $output, new FormattableMarkup('Formatted date field using daterange_custom format displayed as %expected.', ['%expected' => $expected]));
 
     // Test formatters when start date and end date are the same
     $this->drupalGet('entity_test/add');
@@ -531,7 +539,7 @@ public function testAlldayRangeField() {
       "{$field_name}[0][end_value][date]" => $start_date->format($date_format),
     ];
     $this->drupalPostForm(NULL, $edit, t('Save'));
-    preg_match('|entity_test/manage/(\d+)|', $this->url, $match);
+    preg_match('|entity_test/manage/(\d+)|', $this->getUrl(), $match);
     $id = $match[1];
     $this->assertText(t('entity_test @id has been created.', ['@id' => $id]));
 
@@ -550,12 +558,14 @@ public function testAlldayRangeField() {
 
     $start_expected = $this->dateFormatter->format($start_date->getTimestamp(), 'long');
     $start_expected_iso = $this->dateFormatter->format($start_date->getTimestamp(), 'custom', 'Y-m-d\TH:i:s\Z', 'UTC');
+    $start_expected_markup = '<time datetime="' . $start_expected_iso . '" class="datetime">' . $start_expected . '</time>';
     $end_expected = $this->dateFormatter->format($end_date->getTimestamp(), 'long');
     $end_expected_iso = $this->dateFormatter->format($end_date->getTimestamp(), 'custom', 'Y-m-d\TH:i:s\Z', 'UTC');
-    $this->renderTestEntity($id);
-    $this->assertFieldByXPath('//time[@datetime="' . $start_expected_iso . '"]', $start_expected, new FormattableMarkup('Formatted date field using %value format displayed as %expected with %expected_iso attribute.', ['%value' => 'long', '%expected' => $start_expected, '%expected_iso' => $start_expected_iso]));
-    $this->assertFieldByXPath('//time[@datetime="' . $end_expected_iso . '"]', $end_expected, new FormattableMarkup('Formatted date field using %value format displayed as %expected with %expected_iso attribute.', ['%value' => 'long', '%expected' => $end_expected, '%expected_iso' => $end_expected_iso]));
-    $this->assertText(' THESEPARATOR ', 'Found proper separator');
+    $end_expected_markup = '<time datetime="' . $end_expected_iso . '" class="datetime">' . $end_expected . '</time>';
+    $output = $this->renderTestEntity($id);
+    $this->assertContains($start_expected_markup, $output, new FormattableMarkup('Formatted date field using %value format displayed as %expected with %expected_iso attribute.', ['%value' => 'long', '%expected' => $start_expected, '%expected_iso' => $start_expected_iso]));
+    $this->assertContains($end_expected_markup, $output, new FormattableMarkup('Formatted date field using %value format displayed as %expected with %expected_iso attribute.', ['%value' => 'long', '%expected' => $end_expected, '%expected_iso' => $end_expected_iso]));
+    $this->assertContains(' THESEPARATOR ', $output, 'Found proper separator');
 
     // Verify that hook_entity_prepare_view can add attributes.
     // @see entity_test_entity_prepare_view()
@@ -567,9 +577,9 @@ public function testAlldayRangeField() {
       ->setComponent($field_name, $this->displayOptions)
       ->save();
     $expected = $start_date->format(DATETIME_DATETIME_STORAGE_FORMAT) . ' THESEPARATOR ' . $end_date->format(DATETIME_DATETIME_STORAGE_FORMAT);
-    $this->renderTestEntity($id);
-    $this->assertText($expected, new FormattableMarkup('Formatted date field using plain format displayed as %expected.', ['%expected' => $expected]));
-    $this->assertText(' THESEPARATOR ', 'Found proper separator');
+    $output = $this->renderTestEntity($id);
+    $this->assertContains($expected, $output, new FormattableMarkup('Formatted date field using plain format displayed as %expected.', ['%expected' => $expected]));
+    $this->assertContains(' THESEPARATOR ', $output, 'Found proper separator');
 
     $this->displayOptions['type'] = 'daterange_custom';
     $this->displayOptions['settings']['date_format'] = 'm/d/Y';
@@ -577,9 +587,9 @@ public function testAlldayRangeField() {
       ->setComponent($field_name, $this->displayOptions)
       ->save();
     $expected = $start_date->format($this->displayOptions['settings']['date_format']) . ' THESEPARATOR ' . $end_date->format($this->displayOptions['settings']['date_format']);
-    $this->renderTestEntity($id);
-    $this->assertText($expected, new FormattableMarkup('Formatted date field using daterange_custom format displayed as %expected.', ['%expected' => $expected]));
-    $this->assertText(' THESEPARATOR ', 'Found proper separator');
+    $output = $this->renderTestEntity($id);
+    $this->assertContains($expected, $output, new FormattableMarkup('Formatted date field using daterange_custom format displayed as %expected.', ['%expected' => $expected]));
+    $this->assertContains(' THESEPARATOR ', $output, 'Found proper separator');
 
   }
 
@@ -606,7 +616,7 @@ public function testDatelistWidget() {
 
     // Display creation form.
     $this->drupalGet('entity_test/add');
-    $this->assertFieldByXPath('//fieldset[@id="edit-' . $field_name . '-0"]/legend//text()', $field_name, 'Fieldset and label found');
+    $this->assertFieldByXPath('//fieldset[@id="edit-' . $field_name . '-0"]/legend', $field_name, 'Fieldset and label found');
     $this->assertFieldByXPath('//fieldset[@aria-describedby="edit-' . $field_name . '-0--description"]', NULL, 'ARIA described-by found');
     $this->assertFieldByXPath('//div[@id="edit-' . $field_name . '-0--description"]', NULL, 'ARIA description found');
 
@@ -622,7 +632,7 @@ public function testDatelistWidget() {
     $this->drupalGet($fieldEditUrl);
 
     // Click on the widget settings button to open the widget settings form.
-    $this->drupalPostAjaxForm(NULL, [], $field_name . "_settings_edit");
+    $this->drupalPostForm(NULL, [], $field_name . "_settings_edit");
     $xpathIncr = "//select[starts-with(@id, \"edit-fields-$field_name-settings-edit-form-settings-increment\")]";
     $this->assertNoFieldByXPath($xpathIncr, NULL, 'Increment element not found for Date Only.');
 
@@ -656,7 +666,7 @@ public function testDatelistWidget() {
     $this->drupalGet($fieldEditUrl);
 
     // Click on the widget settings button to open the widget settings form.
-    $this->drupalPostAjaxForm(NULL, [], $field_name . "_settings_edit");
+    $this->drupalPostForm(NULL, [], $field_name . "_settings_edit");
     $xpathIncr = "//select[starts-with(@id, \"edit-fields-$field_name-settings-edit-form-settings-increment\")]";
     $this->assertNoFieldByXPath($xpathIncr, NULL, 'Increment element not found for Date Only.');
 
@@ -683,7 +693,7 @@ public function testDatelistWidget() {
     $this->drupalGet($fieldEditUrl);
 
     // Click on the widget settings button to open the widget settings form.
-    $this->drupalPostAjaxForm(NULL, [], $field_name . "_settings_edit");
+    $this->drupalPostForm(NULL, [], $field_name . "_settings_edit");
     $this->assertFieldByXPath($xpathIncr, NULL, 'Increment element found for Date and time.');
 
     // Display creation form.
@@ -712,7 +722,7 @@ public function testDatelistWidget() {
     }
 
     $this->drupalPostForm(NULL, $edit, t('Save'));
-    preg_match('|entity_test/manage/(\d+)|', $this->url, $match);
+    preg_match('|entity_test/manage/(\d+)|', $this->getUrl(), $match);
     $id = $match[1];
     $this->assertText(t('entity_test @id has been created.', ['@id' => $id]));
 
@@ -767,7 +777,7 @@ public function testDatelistWidget() {
     }
 
     $this->drupalPostForm(NULL, $edit, t('Save'));
-    preg_match('|entity_test/manage/(\d+)|', $this->url, $match);
+    preg_match('|entity_test/manage/(\d+)|', $this->getUrl(), $match);
     $id = $match[1];
     $this->assertText(t('entity_test @id has been created.', ['@id' => $id]));
 
@@ -834,7 +844,7 @@ public function testDatelistWidget() {
 
     $this->drupalPostForm(NULL, $edit, t('Save'));
     $this->assertResponse(200);
-    preg_match('|entity_test/manage/(\d+)|', $this->url, $match);
+    preg_match('|entity_test/manage/(\d+)|', $this->getUrl(), $match);
     $id = $match[1];
     $this->assertText(t('entity_test @id has been created.', ['@id' => $id]));