EmptyBoot class Drush\Boot lib/Drush/Boot/EmptyBoot.php This is a do-nothing 'Boot' class that is used when there is no site at --root, or when no root is specified.
FileCache class Drush\Cache lib/Drush/Cache/FileCache.php Default cache implementation.
FilesystemCase class Unish tests/filesystemTest.php Filesystem related testing.
initCommandCase class Unish tests/initCommandTest.php Test to see if the `drush init` command does the setup that it is supposed to do.
JSONCache class Drush\Cache lib/Drush/Cache/JSONCache.php JSON cache storage backend.
LogLevel class Drush\Log lib/Drush/Log/LogLevel.php Additional log levels that Drush uses for historical reasons. Standard log levels should be preferred.
outputFormatCase class Unish tests/outputFormatTest.php @todo, Consider removing these tests now that we have outputFormatUnitCase.
Project class Drush\UpdateService lib/Drush/UpdateService/Project.php Representation of a project's release info from the update service.
QueueInterface interface Drush\Queue lib/Drush/Queue/QueueInterface.php Defines an interface for interacting with queues.
quickDrupalCase class Unish tests/quickDrupalTest.php core-quick-drupal tests.
ReleaseInfo class Drush\UpdateService lib/Drush/UpdateService/ReleaseInfo.php Release info engine class.