We didn't end up adding BehatHTMLFormatter plugin as part of upgrade to Behat 3 as it's a third party plugin. You can do following to use it on your test server.
- Add following to your config.php
$CFG->behat_config = array(
'default' => array(
'formatters' => array(
'html' => array(
'output_path' => '/home/rajesh/Desktop'
'extensions' => array(
'emuse\BehatHTMLFormatter\BehatHTMLFormatterExtension' => array(
'name' => 'html',
'renderer' => 'Twig,Behat2',
'file_name' => 'index',
'print_args' => true,
'print_outp' => true,
'loop_break' => true
- Initialize behat (php admin/tool/behat/cli/init.php)
- run "php composer.phar require --dev emuse/behat-html-formatter"
As per failed steps, it seems it will be helpful formatter, feel free to create an issue and I will be happy to add that as part of moodle-behat-extension