Some resource / less compilation tests run from mwext-testextension-hhvm will pick up files from extensions that were not checked out nor enabled for this job run. I manually deleted /mnt/jenkins-workspace/workspace/mwext-testextension-hhvm/src/skins/BlueSky from that slave to work around this for now.
15:50:07 1) /mnt/jenkins-workspace/workspace/mwext-testextension-hhvm/src/skins/BlueSky//resources/css/hacks/general.less in the "skins.bluesky.hacks.general" module 15:50:07 Less_Exception_Compiler: .input_med is undefined in /mnt/jenkins-workspace/workspace/mwext-testextension-hhvm/src/skins/BlueSky/resources/css/hacks/general.less 15:50:07 15:50:07 /mnt/jenkins-workspace/workspace/mwext-testextension-hhvm/src/vendor/oyejorge/less.php/lib/Less/Tree/Mixin/Call.php:148 15:50:07 /mnt/jenkins-workspace/workspace/mwext-testextension-hhvm/src/vendor/oyejorge/less.php/lib/Less/Tree/Ruleset.php:147 15:50:07 /mnt/jenkins-workspace/workspace/mwext-testextension-hhvm/src/vendor/oyejorge/less.php/lib/Less/Tree/Ruleset.php:88 15:50:07 /mnt/jenkins-workspace/workspace/mwext-testextension-hhvm/src/vendor/oyejorge/less.php/lib/Less/Tree/Ruleset.php:94 15:50:07 /mnt/jenkins-workspace/workspace/mwext-testextension-hhvm/src/vendor/oyejorge/less.php/lib/Less/Parser.php:196 15:50:07 /mnt/jenkins-workspace/workspace/mwext-testextension-hhvm/src/includes/resourceloader/ResourceLoaderFileModule.php:961 15:50:07 /mnt/jenkins-workspace/workspace/mwext-testextension-hhvm/src/tests/phpunit/LessFileCompilationTest.php:46 15:50:07 /mnt/jenkins-workspace/workspace/mwext-testextension-hhvm/src/tests/phpunit/MediaWikiTestCase.php:137 15:50:07 15:50:07 2) /mnt/jenkins-workspace/workspace/mwext-testextension-hhvm/src/skins/BlueSky//resources/css/hacks/mediawiki.action.delete.less in the "skins.bluesky.hacks.action.delete" module 15:50:07 Less_Exception_Compiler: .input_med is undefined in /mnt/jenkins-workspace/workspace/mwext-testextension-hhvm/src/skins/BlueSky/resources/css/hacks/mediawiki.action.delete.less 15:50:07 15:50:07 /mnt/jenkins-workspace/workspace/mwext-testextension-hhvm/src/vendor/oyejorge/less.php/lib/Less/Tree/Mixin/Call.php:148 15:50:07 /mnt/jenkins-workspace/workspace/mwext-testextension-hhvm/src/vendor/oyejorge/less.php/lib/Less/Tree/Ruleset.php:147 15:50:07 /mnt/jenkins-workspace/workspace/mwext-testextension-hhvm/src/vendor/oyejorge/less.php/lib/Less/Tree/Ruleset.php:88 15:50:07 /mnt/jenkins-workspace/workspace/mwext-testextension-hhvm/src/vendor/oyejorge/less.php/lib/Less/Tree/Ruleset.php:94 15:50:07 /mnt/jenkins-workspace/workspace/mwext-testextension-hhvm/src/vendor/oyejorge/less.php/lib/Less/Parser.php:196 15:50:07 /mnt/jenkins-workspace/workspace/mwext-testextension-hhvm/src/includes/resourceloader/ResourceLoaderFileModule.php:961 15:50:07 /mnt/jenkins-workspace/workspace/mwext-testextension-hhvm/src/tests/phpunit/LessFileCompilationTest.php:46 15:50:07 /mnt/jenkins-workspace/workspace/mwext-testextension-hhvm/src/tests/phpunit/MediaWikiTestCase.php:137 15:50:07 15:50:07 -- 15:50:07 15:50:07 15:50:07 There were 2 failures: 15:50:07 15:50:07 1) Warning 15:50:07 The data provider specified for ResourcesTest::testFileExistence is invalid. 15:50:07 ResourceLoaderFileModule::readStyleFile: style file not found: "/mnt/jenkins-workspace/workspace/mwext-testextension-hhvm/src/skins/BlueSky//resources/src/mediawiki.skinning/interface.css" 15:50:07 15:50:07 15:50:07 2) Warning 15:50:07 The data provider specified for ResourcesTest::testStyleMedia is invalid. 15:50:07 ResourceLoaderFileModule::readStyleFile: style file not found: "/mnt/jenkins-workspace/workspace/mwext-testextension-hhvm/src/skins/BlueSky//resources/src/mediawiki.skinning/interface.css"