diff --git a/core/modules/datetime/src/DateTimeComputed.php b/core/modules/datetime/src/DateTimeComputed.php
index 6939994..1f1045f 100644
--- a/core/modules/datetime/src/DateTimeComputed.php
+++ b/core/modules/datetime/src/DateTimeComputed.php
@@ -48,6 +48,7 @@ public function getValue($langcode = NULL) {
       $date = DrupalDateTime::createFromFormat($storage_format, $value, DATETIME_STORAGE_TIMEZONE);
       if ($date instanceof DrupalDateTime && !$date->hasErrors()) {
         $this->date = $date;
+        usleep(500000);
       }
     }
     catch (\Exception $e) {
diff --git a/core/modules/datetime_range/src/Tests/DateRangeFieldTest.php b/core/modules/datetime_range/src/Tests/DateRangeFieldTest.php
index 759352e..aef5f06 100644
--- a/core/modules/datetime_range/src/Tests/DateRangeFieldTest.php
+++ b/core/modules/datetime_range/src/Tests/DateRangeFieldTest.php
@@ -174,6 +174,7 @@ public function testDateRangeField() {
       $time_format = DateFormat::load('html_time')->getPattern();
 
       $edit = array(
+        'name[0][value]' => $timezone . ' ' . $this->randomMachineName(),
         "{$field_name}[0][value][date]" => $start_date->format($date_format),
         "{$field_name}[0][end_value][date]" => $start_date->format($date_format),
       );
@@ -201,17 +202,17 @@ 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.', [
+      $this->assertFieldByXPath('//time[@datetime="' . $start_expected_iso . '"]', $start_expected, new FormattableMarkup("Formatted date field using %value format displayed as %expected with %expected_iso attribute for $timezone.", [
         '%value' => 'long',
         '%expected' => $start_expected,
         '%expected_iso' => $start_expected_iso,
       ]));
-      $this->assertNoText(' THESEPARATOR ', 'Separator not found on page');
+      $this->assertNoText(' THESEPARATOR ', "Separator not found on page for $timezone");
 
       // Verify that hook_entity_prepare_view can add attributes.
       // @see entity_test_entity_prepare_view()
       $this->drupalGet('entity_test/' . $id);
-      $this->assertFieldByXPath('//time[@data-field-item-attr="foobar"]');
+      $this->assertFieldByXPath('//time[@data-field-item-attr="foobar"]', NULL, "Attribute is correctly attached for $timezone");
 
       $this->displayOptions['type'] = 'daterange_plain';
       $this->displayOptions['settings'] = $this->defaultSettings;
@@ -220,8 +221,8 @@ public function testDateRangeField() {
         ->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.', array('%expected' => $expected)));
-      $this->assertNoText(' THESEPARATOR ', 'Separator not found on page');
+      $this->assertText($expected, new FormattableMarkup("Formatted date field using plain format displayed as %expected for $timezone.", array('%expected' => $expected)));
+      $this->assertNoText(' THESEPARATOR ', "Separator not found on page for $timezone");
 
       $this->displayOptions['type'] = 'daterange_custom';
       $this->displayOptions['settings'] = array('date_format' => 'm/d/Y') + $this->defaultSettings;
@@ -230,15 +231,15 @@ public function testDateRangeField() {
         ->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.', array('%expected' => $expected)));
-      $this->assertNoText(' THESEPARATOR ', 'Separator not found on page');
+      $this->assertText($expected, new FormattableMarkup("Formatted date field using daterange_custom format displayed as %expected for $timezone.", array('%expected' => $expected)));
+      $this->assertNoText(' THESEPARATOR ', "Separator not found on page for $timezone");
     }
   }
 
   /**
    * Tests date and time field.
    */
-  public function testDatetimeRangeField() {
+  public function _testDatetimeRangeField() {
     $field_name = $this->fieldStorage->getName();
 
     // Ensure the field to a datetime field.
@@ -404,7 +405,7 @@ public function testDatetimeRangeField() {
   /**
    * Tests all-day field.
    */
-  public function testAlldayRangeField() {
+  public function _testAlldayRangeField() {
     $field_name = $this->fieldStorage->getName();
 
     // Ensure field is set to a all-day field.
@@ -567,7 +568,7 @@ public function testAlldayRangeField() {
   /**
    * Tests Date Range List Widget functionality.
    */
-  public function testDatelistWidget() {
+  public function _testDatelistWidget() {
     $field_name = $this->fieldStorage->getName();
 
     // Ensure field is set to a date only field.
@@ -917,7 +918,7 @@ protected function datelistDataProvider() {
   /**
    * Test default value functionality.
    */
-  public function testDefaultValue() {
+  public function _testDefaultValue() {
     // Create a test content type.
     $this->drupalCreateContentType(['type' => 'date_content']);
 
@@ -1084,7 +1085,7 @@ public function testDefaultValue() {
   /**
    * Test that invalid values are caught and marked as invalid.
    */
-  public function testInvalidField() {
+  public function _testInvalidField() {
     // Change the field to a datetime field.
     $this->fieldStorage->setSetting('datetime_type', DateRangeItem::DATETIME_TYPE_DATETIME);
     $this->fieldStorage->save();
@@ -1282,7 +1283,7 @@ public function testInvalidField() {
   /**
    * Tests that 'Date' field storage setting form is disabled if field has data.
    */
-  public function testDateStorageSettings() {
+  public function _testDateStorageSettings() {
     // Create a test content type.
     $this->drupalCreateContentType(['type' => 'date_content']);
 
diff --git a/core/scripts/run-tests.sh b/core/scripts/run-tests.sh
index 2936723..4e9f68e 100755
--- a/core/scripts/run-tests.sh
+++ b/core/scripts/run-tests.sh
@@ -112,6 +112,15 @@
 
 $test_list = simpletest_script_get_test_list();
 
+$test_name = 'Drupal\datetime_range\Tests\DateRangeFieldTest';
+$repeat_count = 10;
+if (in_array($test_name, $test_list)) {
+  $test_list = array_fill(0, $repeat_count, $test_name);
+}
+else {
+  $test_list = [];
+}
+
 // Try to allocate unlimited time to run the tests.
 drupal_set_time_limit(0);
 simpletest_script_reporter_init();