Issue #2030165 by Berdir, tim.plunkett, vijaycs85, tkuldeep17 | rteijeiro: Convert form_test_* functions to classes.

Issue #697760 by sun: Replace getInfo() in tests with native phpDoc + annotations (following PHPUnit).

Issue #2089331 by grom358 | thedavidmeister: [meta] Replace calls to check_plain() with Drupal\Component\Utility\String::checkPlain().

Issue #2152217 by joelpittet, mgifford, vijaycs85, jjcarrion, sun: Remove theme_form_required_marker() from the theme system - use CSS instead.

Issue #2208609 by sun, Jalandhar, damiankloip: Move Json utility class into Drupal\Component\Serialization.

Issue #2093173 by longwave, Cyberschorsch, forbesgraham, sandipmkhairnar, damiankloip, rbayliss, grom358, harijari, InternetDevels, dawehner: Remove all calls to drupal_json_decode(), use \Drupal\Component\Utility\Json::decode().

Issue #2192419 by sun, mgifford: Use a WCAG-compliant fieldset (fieldgroup) for #type radios/checkboxes.

Issue #2191285 by sun, andypost, jibran, Berdir, alexpott: Text module is not required, but is marked as required.

Issue #1987716 by pfrenssen, tim.plunkett, kgoel: Provide a FormTestBase class to allow PHPUnit form tests.

Issue #2143349 by larowlan: Submitting a form as an anonymous user when $form['#token'] = FALSE results in a notice.

Issue #2121775 by jessebeach: Make the markup associated with the required star on field items silent.

Issue #2080391 by johnmcc, Bladedu, chertzog, jeroen12345: Remove Unused local variables from multiple core files.

Issue #2074037 by Wim Leers, effulgentsia: Add drupalPostUrl() — drupalPost()/drupalPostAjax() are for forms only, D8 JS performs non-form HTTP requests.

Issue #2047075 by Caecus, mgifford, jessebeach, larowlan: Mark invalid form field with [aria-invalid=true].

Issue #799356 by m1n0, jaffaralia, effulgentsia, vijaycs85: Fixed _form_set_class() is too aggressive in assigning the 'error' class.

Issue #501428 by KarenS, swentel, tim.plunkett, webchick, effulgentsia, nod_, scor, Lars Toomre: Added Date and time field type in core.

Issue #78292 by BrockBoland, chx, Traverus, thoufek, patrickd, sun: Fixed Select element with empty options triggers PHP warning.

Issue #1779026 by dagmar, tim.plunkett, sun, heyrocker: Convert Text Formats to Configuration System.

Issue #1238484 by mrfelton, ry5n, aspilicious, Bojhan, Xano, nod_, rootatwc, effulgentsia, chx, sun: Ability to mark the form buttons to be of a specific type (so that they can be styled differently).

Issue #742344 by sun, pillarsdotnet, tarmstrong, neilnz, wamilton, lucascaro: Allow forms to set custom validation error messages on required fields.

Issue #1785436 by Boobaa: Fixed Submission of #required elements without #title and empty value does not display any error.

Issue #1711070 by kid_icarus, tim.plunkett, xjm, droplet, zendoodles and cam8001: Convert tests to use ::$modules property instead of parent::setUp($modules).

Issue #811542 follow-up by David_Rothstein, thekevinday, attiks, quicksketch: Fixed illegal choice errors on radio buttons.