HTML portion of FormValuesTest is not tested

FormValuesTest tests a form that's defined in a test module, ajax_forms_test.

Enabling this and going to /ajax_forms_test_get_form shows a form where each element has an AJAX response. Below each element is a short text, and changing a value causes this text to update with the value, to confirm something has happened in the AJAX callback.

However, this HTML value does not appear to checked by the test -- commenting out the code that produces it does not cause the test to fail.

I am not sure whether this is by design or not -- it could be that the updating text is merely meant for humans manually testing the form while developing the tests?