wikihiero has the same problem as in T85007, though @Legoktm's comment on Patch Set 2 of https://gerrit.wikimedia.org/r/#/c/183906/ seems to suggest that the ResourceLoaderRegisterModules hook should be used instead of $wgExtensionFunctions for conditional registration of modules.
There was 1 error: 1) ResourcesTest::testUnsatisfiableDependencies Undefined index: ext.visualEditor.mwcore /home/ki/Projects/mediawiki/core/tests/phpunit/structure/ResourcesTest.php:94 /home/ki/Projects/mediawiki/core/tests/phpunit/MediaWikiTestCase.php:141 -- There were 2 failures: [...] 2) ResourcesTest::testMissingDependencies The module 'ext.visualEditor.mwcore' required by 'ext.wikihiero.visualEditor' must exist Failed asserting that an array contains 'ext.visualEditor.mwcore'. /home/ki/Projects/mediawiki/core/tests/phpunit/structure/ResourcesTest.php:74 /home/ki/Projects/mediawiki/core/tests/phpunit/MediaWikiTestCase.php:141