The Jenkins job [[ https://integration.wikimedia.org/ci/job/mediawiki-core-code-coverage/ | mediawiki-core-code-coverage ]] produces code coverage for MediaWiki core. It is run on a daily basis and takes a while:
It uses to take almost 4 hours to generate and nowadays a bit less than 2 hours which is still a lot. Build time trend:
The job runs on Trusty instances with Zend PHP5.5 and XDebug. PHPUnit relies on PHP_CodeCoverage which apparently supports Zend PHP 7.0 and phpdbg, the combination being an order of magnitude faster.