I am trying to test my site with Behat.

On my entity edit form, I have a Datetime field that uses the Date and time widget. I want to use the Date and time widget because I need to set the time in increments of seconds, which I cannot do with the Select list widget.

I want to set the value of this field with a step like this:

And I assign the date "yesterday" with timezone "Asia/Tokyo" for "edit-field-datetime-MYFIELD-0-value" 

To do so, in FeatureContext.php, I wrote the following code.

  /**    * @Then I assign the date :date with timezone :timezone for :field    *    * Assign the specified date to the element with the given CSS.    */   public function assertEnterDateForField($field, $timezone, $date_string) {     $date_field = $field . '-date';     $time_field = $field . '-time';     // Drupal stores timezones as UTC so we need the base time in UTC.     $datetime = new DateTime($date_string, timezone_open('UTC'));     // We need to convert the UTC time to the user's timezone.     // This is because when saving the entity,     // Drupal will convert the value to UTC.     $datetime->setTimezone(timezone_open($timezone));     $date_output_string = $datetime->format('mdY');     $time_output_string = $datetime->format('hisA');     $datetime_debug_string = $datetime->format('Y-m-dTH:i:sO');     $this->fillfield($time_field, $time_output_string);     $this->fillField($date_field, $date_output_string);     echo "Datetime $datetime_debug_string     Field set to     date: $date_output_string     time: $time_output_string";   } 

On my local environment (lando, running the Standalone Chrome container), this code works as expected; the date/time is set correctly for the field.

However, on my test server (Pantheon/CircleCI, running the Behat Chrome Extension, it doesn’t work. The debug information is correct; for example:

  │ Datetime 2020-08-13T09:00:00+0900   │     Field set to   │     date: 08132020   │     time: 090000AM 

However, the date/time is not actually filled in, so when the entity is saved, the date/time has not been updated.

How can I set the value of a field that uses the Date and time widget with Behat/Mink/Drupal Extension?