PHPUnit tests cannot be rerun from Simpletest UI

Updated: Comment #0

Problem/Motivation

After running a test from the Simpletest UI, you can rerun it from the results form, unless it is a PHPUnit test.
In addition, when rerunning any tests, notices will appear (but only in the dblog, because the UI eats them):

Notice: Undefined index: storage in Drupal\simpletest\Form\SimpletestTestForm->submitForm() (line 104 of /var/www/d8/core/modules/simpletest/lib/Drupal/simpletest/Form/SimpletestTestForm.php).

Warning: array_keys() expects parameter 1 to be array, null given in Drupal\simpletest\Form\SimpletestTestForm->submitForm() (line 104 of /var/www/d8/core/modules/simpletest/lib/Drupal/simpletest/Form/SimpletestTestForm.php).

Warning: in_array() expects parameter 2 to be array, null given in Drupal\simpletest\Form\SimpletestTestForm->submitForm() (line 110 of /var/www/d8/core/modules/simpletest/lib/Drupal/simpletest/Form/SimpletestTestForm.php).

This is because FormInterface::submitForm() is being called directly, and not via FormBuilder::submitForm().
Note that this was a problem before the FormInterface/FormBuilder code, and was a bug in the initial PHPUnit/Simpletest integration.

Once fixing this, any PHPUnit tests using @dataProvider would fail to correctly display the results for the entire testsuite.

Proposed resolution

Use the correct approach to submitting the form, and allow @dataProvider-based tests to be correctly reported.

Remaining tasks

N/A

User interface changes

N/A

API changes

N/A