/**
* Prepares a precompiled ContainerBuilder for all tests of this class.
*
* Avoids repetitive calls to ContainerBuilder::compile(), which is very slow.
*
* Based on the (always identical) list of $modules to enable, an initial
* container is compiled, all instantiated services are reset/removed, and
* this precompiled container is stored in a static class property. (Static,
* because PHPUnit instantiates a new class instance for each test *method*.)
*
* This method is not invoked if there is only a single test method. It is
* also not invoked for tests running in process isolation (since each test
* method runs in a separate process).
*
* The ContainerBuilder is not dumped into the filesystem (which would yield
* an actually compiled Container class), because
*
* 1. PHP code cannot be unloaded, so e.g. 900 tests would load 900 different,
* full Container classes into memory, quickly exceeding any sensible
* memory consumption (GigaBytes).
* 2. Dumping a Container class requires to actually write to the system's
* temporary directory. This is not really easy with vfs, because vfs
* doesn't support yet "include 'vfs://container.php'.". Maybe we could fix
* that upstream.
* 3. PhpDumper is very slow on its own.
*
* @param string[] $modules
* The list of modules to enable.
*
* @return \Drupal\Core\DependencyInjection\ContainerBuilder
* A clone of the precompiled, empty service container.
*/
private function getCompiledContainerBuilder(array $modules)
{
if (!isset(self::$initialContainerBuilder)) {
$kernel = new DrupalKernel('testing', $this->classLoader, FALSE);
$kernel->setSitePath($this->siteDirectory);
if ($modules && ($extensions = $this->getExtensionsForModules($modules))) {
$kernel->updateModules($extensions, $extensions);
}
$kernel->boot();
self::$initialContainerBuilder = $kernel->getContainer();
// Remove all instantiated services, so the container is safe for cloning.
// Technically, ContainerBuilder::set($id, NULL) removes each definition,
// but the container is compiled/frozen already.
foreach (self::$initialContainerBuilder->getServiceIds() as $id) {
self::$initialContainerBuilder->set($id, NULL);
}
// Destruct and trigger garbage collection.
\Drupal::unsetContainer();
$kernel->shutdown();
$kernel = NULL;
// @see register()
$this->container = NULL;
}
$container = clone self::$initialContainerBuilder;
return $container;
}