From 82304ed90fe2c5dc874da0d5641bf865ace5f537 Mon Sep 17 00:00:00 2001
From: Nathaniel Catchpole <catch@35733.no-reply.drupal.org>
Date: Tue, 27 Sep 2016 14:35:22 +0100
Subject: [PATCH] Issue #2776235 by mikeryan, alexpott: Cached autoloader
 misses cause failures when missed class becomes available

---
 .../Component/ClassFinder/ClassFinder.php     |  32 ++
 .../Drupal/Component/ClassFinder/LICENSE.txt  | 339 ++++++++++++++++++
 .../Drupal/Component/ClassFinder/README.txt   |  12 +
 .../Drupal/Component/ClassFinder/TESTING.txt  |  18 +
 .../Component/ClassFinder/composer.json       |  16 +
 core/lib/Drupal/Core/DrupalKernel.php         |  30 +-
 core/modules/migrate/migrate.services.yml     |   2 +-
 ...otatedClassDiscoveryAutomatedProviders.php |  16 +-
 .../src/Plugin/MigrateSourcePluginManager.php |   7 +-
 .../src/Tests/Module/ClassLoaderTest.php      |  14 +
 ...module_install_class_loader_test1.info.yml |   6 +
 ...le_install_class_loader_test1.services.yml |   5 +
 .../src/EventSubscriber.php                   |  29 ++
 ...module_install_class_loader_test2.info.yml |   8 +
 ...le_install_class_loader_test2.services.yml |   5 +
 .../src/EventSubscriber.php                   |  19 +
 .../Component/ClassFinder/ClassFinderTest.php |  39 ++
 17 files changed, 578 insertions(+), 19 deletions(-)
 create mode 100644 core/lib/Drupal/Component/ClassFinder/ClassFinder.php
 create mode 100644 core/lib/Drupal/Component/ClassFinder/LICENSE.txt
 create mode 100644 core/lib/Drupal/Component/ClassFinder/README.txt
 create mode 100644 core/lib/Drupal/Component/ClassFinder/TESTING.txt
 create mode 100644 core/lib/Drupal/Component/ClassFinder/composer.json
 create mode 100644 core/modules/system/tests/modules/module_install_class_loader_test1/module_install_class_loader_test1.info.yml
 create mode 100644 core/modules/system/tests/modules/module_install_class_loader_test1/module_install_class_loader_test1.services.yml
 create mode 100644 core/modules/system/tests/modules/module_install_class_loader_test1/src/EventSubscriber.php
 create mode 100644 core/modules/system/tests/modules/module_install_class_loader_test2/module_install_class_loader_test2.info.yml
 create mode 100644 core/modules/system/tests/modules/module_install_class_loader_test2/module_install_class_loader_test2.services.yml
 create mode 100644 core/modules/system/tests/modules/module_install_class_loader_test2/src/EventSubscriber.php
 create mode 100644 core/tests/Drupal/Tests/Component/ClassFinder/ClassFinderTest.php

diff --git a/core/lib/Drupal/Component/ClassFinder/ClassFinder.php b/core/lib/Drupal/Component/ClassFinder/ClassFinder.php
new file mode 100644
index 00000000000..346f7f66cd8
--- /dev/null
+++ b/core/lib/Drupal/Component/ClassFinder/ClassFinder.php
@@ -0,0 +1,32 @@
+<?php
+
+namespace Drupal\Component\ClassFinder;
+
+use Doctrine\Common\Reflection\ClassFinderInterface;
+
+/**
+ * A Utility class that uses active autoloaders to find a file for a class.
+ */
+class ClassFinder implements ClassFinderInterface {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function findFile($class) {
+    $loaders = spl_autoload_functions();
+    foreach ($loaders as $loader) {
+      if (is_array($loader) && isset($loader[0]) && is_object($loader[0]) && method_exists($loader[0], 'findFile')) {
+        $file = call_user_func_array([$loader[0], 'findFile'], [$class]);
+        // Different implementations return different empty values. For example,
+        // \Composer\Autoload\ClassLoader::findFile() returns FALSE whilst
+        // \Doctrine\Common\Reflection\ClassFinderInterface::findFile()
+        // documents that a NULL should be returned.
+        if (!empty($file)) {
+          return $file;
+        }
+      }
+    }
+    return NULL;
+  }
+
+}
diff --git a/core/lib/Drupal/Component/ClassFinder/LICENSE.txt b/core/lib/Drupal/Component/ClassFinder/LICENSE.txt
new file mode 100644
index 00000000000..94fb84639c4
--- /dev/null
+++ b/core/lib/Drupal/Component/ClassFinder/LICENSE.txt
@@ -0,0 +1,339 @@
+        GNU GENERAL PUBLIC LICENSE
+           Version 2, June 1991
+
+ Copyright (C) 1989, 1991 Free Software Foundation, Inc.,
+ 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
+
+          Preamble
+
+  The licenses for most software are designed to take away your
+freedom to share and change it.  By contrast, the GNU General Public
+License is intended to guarantee your freedom to share and change free
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+Foundation's software and to any other program whose authors commit to
+using it.  (Some other Free Software Foundation software is covered by
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+    (at your option) any later version.
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+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
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+    with this program; if not, write to the Free Software Foundation, Inc.,
+    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
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+    Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
+    This is free software, and you are welcome to redistribute it
+    under certain conditions; type `show c' for details.
+
+The hypothetical commands `show w' and `show c' should show the appropriate
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+be called something other than `show w' and `show c'; they could even be
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+  `Gnomovision' (which makes passes at compilers) written by James Hacker.
+
+  <signature of Ty Coon>, 1 April 1989
+  Ty Coon, President of Vice
+
+This General Public License does not permit incorporating your program into
+proprietary programs.  If your program is a subroutine library, you may
+consider it more useful to permit linking proprietary applications with the
+library.  If this is what you want to do, use the GNU Lesser General
+Public License instead of this License.
diff --git a/core/lib/Drupal/Component/ClassFinder/README.txt b/core/lib/Drupal/Component/ClassFinder/README.txt
new file mode 100644
index 00000000000..425e97b5a51
--- /dev/null
+++ b/core/lib/Drupal/Component/ClassFinder/README.txt
@@ -0,0 +1,12 @@
+The Drupal ClassFinder Component
+
+Thanks for using this Drupal component.
+
+You can participate in its development on Drupal.org, through our issue system:
+https://www.drupal.org/project/issues/drupal
+
+You can get the full Drupal repo here:
+https://www.drupal.org/project/drupal/git-instructions
+
+You can browse the full Drupal repo here:
+http://cgit.drupalcode.org/drupal
diff --git a/core/lib/Drupal/Component/ClassFinder/TESTING.txt b/core/lib/Drupal/Component/ClassFinder/TESTING.txt
new file mode 100644
index 00000000000..c7e97fc955d
--- /dev/null
+++ b/core/lib/Drupal/Component/ClassFinder/TESTING.txt
@@ -0,0 +1,18 @@
+HOW-TO: Test this Drupal component
+
+In order to test this component, you'll need to get the entire Drupal repo and
+run the tests there.
+
+You'll find the tests under core/tests/Drupal/Tests/Component.
+
+You can get the full Drupal repo here:
+https://www.drupal.org/project/drupal/git-instructions
+
+You can find more information about running PHPUnit tests with Drupal here:
+https://www.drupal.org/node/2116263
+
+Each component in the Drupal\Component namespace has its own annotated test
+group. You can use this group to run only the tests for this component. Like
+this:
+
+$ ./vendor/bin/phpunit -c core --group ClassFinder
diff --git a/core/lib/Drupal/Component/ClassFinder/composer.json b/core/lib/Drupal/Component/ClassFinder/composer.json
new file mode 100644
index 00000000000..97d36687755
--- /dev/null
+++ b/core/lib/Drupal/Component/ClassFinder/composer.json
@@ -0,0 +1,16 @@
+{
+  "name": "drupal/core-class-finder",
+  "description": "This class provides a class finding utility.",
+  "keywords": ["drupal"],
+  "homepage": "https://www.drupal.org/project/drupal",
+  "license": "GPL-2.0+",
+  "require": {
+    "php": ">=5.5.9",
+    "doctrine/common": "2.5.*"
+  },
+  "autoload": {
+    "psr-4": {
+      "Drupal\\Component\\ClassFinder\\": ""
+    }
+  }
+}
diff --git a/core/lib/Drupal/Core/DrupalKernel.php b/core/lib/Drupal/Core/DrupalKernel.php
index ab2f645c87d..ba2c0fbd237 100644
--- a/core/lib/Drupal/Core/DrupalKernel.php
+++ b/core/lib/Drupal/Core/DrupalKernel.php
@@ -2,6 +2,7 @@
 
 namespace Drupal\Core;
 
+use Composer\Autoload\ClassLoader;
 use Drupal\Component\Assertion\Handle;
 use Drupal\Component\FileCache\FileCacheFactory;
 use Drupal\Component\Utility\Unicode;
@@ -761,6 +762,10 @@ class DrupalKernel implements DrupalKernelInterface, TerminableInterface {
    *   needed.
    */
   public function updateModules(array $module_list, array $module_filenames = array()) {
+    $pre_existing_module_namespaces = [];
+    if ($this->booted && is_array($this->moduleList)) {
+      $pre_existing_module_namespaces = $this->getModuleNamespacesPsr4($this->getModuleFileNames());
+    }
     $this->moduleList = $module_list;
     foreach ($module_filenames as $name => $extension) {
       $this->moduleData[$name] = $extension;
@@ -773,6 +778,20 @@ class DrupalKernel implements DrupalKernelInterface, TerminableInterface {
     // container in order to refresh the serviceProvider list and container.
     $this->containerNeedsRebuild = TRUE;
     if ($this->booted) {
+      // We need to register any new namespaces to a new class loader because
+      // the current class loader might have stored a negative result for a
+      // class that is now available.
+      // @see \Composer\Autoload\ClassLoader::findFile()
+      $new_namespaces = array_diff_key(
+        $this->getModuleNamespacesPsr4($this->getModuleFileNames()),
+        $pre_existing_module_namespaces
+      );
+      if (!empty($new_namespaces)) {
+        $additional_class_loader = new ClassLoader();
+        $this->classLoaderAddMultiplePsr4($new_namespaces, $additional_class_loader);
+        $additional_class_loader->register();
+      }
+
       $this->initializeContainer();
     }
   }
@@ -1387,8 +1406,15 @@ class DrupalKernel implements DrupalKernelInterface, TerminableInterface {
    *   Array where each key is a namespace like 'Drupal\system', and each value
    *   is either a PSR-4 base directory, or an array of PSR-4 base directories
    *   associated with this namespace.
+   * @param object $class_loader
+   *   The class loader. Normally \Composer\Autoload\ClassLoader, as included by
+   *   the front controller, but may also be decorated; e.g.,
+   *   \Symfony\Component\ClassLoader\ApcClassLoader.
    */
-  protected function classLoaderAddMultiplePsr4(array $namespaces = array()) {
+  protected function classLoaderAddMultiplePsr4(array $namespaces = array(), $class_loader = NULL) {
+    if ($class_loader === NULL) {
+      $class_loader = $this->classLoader;
+    }
     foreach ($namespaces as $prefix => $paths) {
       if (is_array($paths)) {
         foreach ($paths as $key => $value) {
@@ -1398,7 +1424,7 @@ class DrupalKernel implements DrupalKernelInterface, TerminableInterface {
       elseif (is_string($paths)) {
         $paths = $this->root . '/' . $paths;
       }
-      $this->classLoader->addPsr4($prefix . '\\', $paths);
+      $class_loader->addPsr4($prefix . '\\', $paths);
     }
   }
 
diff --git a/core/modules/migrate/migrate.services.yml b/core/modules/migrate/migrate.services.yml
index c9a64570199..efbaedd221b 100644
--- a/core/modules/migrate/migrate.services.yml
+++ b/core/modules/migrate/migrate.services.yml
@@ -7,7 +7,7 @@ services:
     arguments: [migrate]
   plugin.manager.migrate.source:
     class: Drupal\migrate\Plugin\MigrateSourcePluginManager
-    arguments: [source, '@container.namespaces', '@cache.discovery', '@module_handler', '@class_loader']
+    arguments: [source, '@container.namespaces', '@cache.discovery', '@module_handler']
   plugin.manager.migrate.process:
     class: Drupal\migrate\Plugin\MigratePluginManager
     arguments: [process, '@container.namespaces', '@cache.discovery', '@module_handler', 'Drupal\migrate\Annotation\MigrateProcessPlugin']
diff --git a/core/modules/migrate/src/Plugin/Discovery/AnnotatedClassDiscoveryAutomatedProviders.php b/core/modules/migrate/src/Plugin/Discovery/AnnotatedClassDiscoveryAutomatedProviders.php
index aba60b19e38..c102bb890ef 100644
--- a/core/modules/migrate/src/Plugin/Discovery/AnnotatedClassDiscoveryAutomatedProviders.php
+++ b/core/modules/migrate/src/Plugin/Discovery/AnnotatedClassDiscoveryAutomatedProviders.php
@@ -6,6 +6,7 @@ use Doctrine\Common\Annotations\AnnotationRegistry;
 use Doctrine\Common\Reflection\StaticReflectionParser as BaseStaticReflectionParser;
 use Drupal\Component\Annotation\AnnotationInterface;
 use Drupal\Component\Annotation\Reflection\MockFileFinder;
+use Drupal\Component\ClassFinder\ClassFinder;
 use Drupal\Core\Plugin\Discovery\AnnotatedClassDiscovery;
 use Drupal\migrate\Annotation\MultipleProviderAnnotationInterface;
 
@@ -20,9 +21,9 @@ use Drupal\migrate\Annotation\MultipleProviderAnnotationInterface;
 class AnnotatedClassDiscoveryAutomatedProviders extends AnnotatedClassDiscovery {
 
   /**
-   * Any class loader with a findFile() method.
+   * A utility object that can use active autoloaders to find files for classes.
    *
-   * @var \Composer\Autoload\ClassLoader
+   * @var \Doctrine\Common\Reflection\ClassFinderInterface
    */
   protected $finder;
 
@@ -41,17 +42,10 @@ class AnnotatedClassDiscoveryAutomatedProviders extends AnnotatedClassDiscovery
    *   Defaults to 'Drupal\Component\Annotation\Plugin'.
    * @param string[] $annotation_namespaces
    *   Additional namespaces to scan for annotation definitions.
-   * @param $class_loader
-   *   The class loader already knows where to find the classes so it is reused
-   *   as the class finder.
    */
-  public function __construct($subdir, \Traversable $root_namespaces, $plugin_definition_annotation_name = 'Drupal\Component\Annotation\Plugin', array $annotation_namespaces = [], $class_loader) {
+  public function __construct($subdir, \Traversable $root_namespaces, $plugin_definition_annotation_name = 'Drupal\Component\Annotation\Plugin', array $annotation_namespaces = []) {
     parent::__construct($subdir, $root_namespaces, $plugin_definition_annotation_name, $annotation_namespaces);
-
-    if (!method_exists($class_loader, 'findFile')) {
-      throw new \LogicException(sprintf('Class loader (%s) must implement findFile() method', get_class($class_loader)));
-    }
-    $this->finder = $class_loader;
+    $this->finder = new ClassFinder();
   }
 
 
diff --git a/core/modules/migrate/src/Plugin/MigrateSourcePluginManager.php b/core/modules/migrate/src/Plugin/MigrateSourcePluginManager.php
index 34ac0c54b53..1aaf4f180e3 100644
--- a/core/modules/migrate/src/Plugin/MigrateSourcePluginManager.php
+++ b/core/modules/migrate/src/Plugin/MigrateSourcePluginManager.php
@@ -40,12 +40,9 @@ class MigrateSourcePluginManager extends MigratePluginManager {
    *   Cache backend instance to use.
    * @param \Drupal\Core\Extension\ModuleHandlerInterface $module_handler
    *   The module handler to invoke the alter hook with.
-   * @param object $class_loader
-   *   The class loader.
    */
-  public function __construct($type, \Traversable $namespaces, CacheBackendInterface $cache_backend, ModuleHandlerInterface $module_handler, $class_loader) {
+  public function __construct($type, \Traversable $namespaces, CacheBackendInterface $cache_backend, ModuleHandlerInterface $module_handler) {
     parent::__construct($type, $namespaces, $cache_backend, $module_handler, 'Drupal\migrate\Annotation\MigrateSource');
-    $this->classLoader = $class_loader;
   }
 
   /**
@@ -53,7 +50,7 @@ class MigrateSourcePluginManager extends MigratePluginManager {
    */
   protected function getDiscovery() {
     if (!$this->discovery) {
-      $discovery = new AnnotatedClassDiscoveryAutomatedProviders($this->subdir, $this->namespaces, $this->pluginDefinitionAnnotationName, $this->additionalAnnotationNamespaces, $this->classLoader);
+      $discovery = new AnnotatedClassDiscoveryAutomatedProviders($this->subdir, $this->namespaces, $this->pluginDefinitionAnnotationName, $this->additionalAnnotationNamespaces);
       $this->discovery = new ContainerDerivativeDiscoveryDecorator($discovery);
     }
     return $this->discovery;
diff --git a/core/modules/system/src/Tests/Module/ClassLoaderTest.php b/core/modules/system/src/Tests/Module/ClassLoaderTest.php
index 1e7a0a54f76..bc2dfd5fc72 100644
--- a/core/modules/system/src/Tests/Module/ClassLoaderTest.php
+++ b/core/modules/system/src/Tests/Module/ClassLoaderTest.php
@@ -70,4 +70,18 @@ class ClassLoaderTest extends WebTestBase {
     }
   }
 
+  /**
+   * Ensures the negative caches in the class loader don't result in crashes.
+   */
+  public function testMultipleModules() {
+    $this->drupalLogin($this->rootUser);
+    $edit = [
+      "modules[Testing][module_install_class_loader_test1][enable]" => TRUE,
+      "modules[Testing][module_install_class_loader_test2][enable]" => TRUE,
+    ];
+    $this->drupalPostForm('admin/modules', $edit, t('Install'));
+    $this->rebuildContainer();
+    $this->assertTrue(\Drupal::moduleHandler()->moduleExists('module_install_class_loader_test2'), 'The module_install_class_loader_test2 module has been installed.');
+  }
+
 }
diff --git a/core/modules/system/tests/modules/module_install_class_loader_test1/module_install_class_loader_test1.info.yml b/core/modules/system/tests/modules/module_install_class_loader_test1/module_install_class_loader_test1.info.yml
new file mode 100644
index 00000000000..83c54d91e4b
--- /dev/null
+++ b/core/modules/system/tests/modules/module_install_class_loader_test1/module_install_class_loader_test1.info.yml
@@ -0,0 +1,6 @@
+name: 'Module install class loader test1'
+description: 'Support module for tests that the class loader behaves as expected during module install.'
+type: module
+package: Testing
+core: 8.x
+version: VERSION
diff --git a/core/modules/system/tests/modules/module_install_class_loader_test1/module_install_class_loader_test1.services.yml b/core/modules/system/tests/modules/module_install_class_loader_test1/module_install_class_loader_test1.services.yml
new file mode 100644
index 00000000000..71b5d585ba7
--- /dev/null
+++ b/core/modules/system/tests/modules/module_install_class_loader_test1/module_install_class_loader_test1.services.yml
@@ -0,0 +1,5 @@
+services:
+  module_install_class_loader_test1.event_subscriber:
+    class: Drupal\module_install_class_loader_test1\EventSubscriber
+    tags:
+      - { name: event_subscriber }
diff --git a/core/modules/system/tests/modules/module_install_class_loader_test1/src/EventSubscriber.php b/core/modules/system/tests/modules/module_install_class_loader_test1/src/EventSubscriber.php
new file mode 100644
index 00000000000..ce0ef4981ae
--- /dev/null
+++ b/core/modules/system/tests/modules/module_install_class_loader_test1/src/EventSubscriber.php
@@ -0,0 +1,29 @@
+<?php
+
+namespace Drupal\module_install_class_loader_test1;
+
+use Symfony\Component\EventDispatcher\EventSubscriberInterface;
+
+/**
+ * An event subscriber that does different things depending on whether classes
+ * exist.
+ */
+class EventSubscriber implements EventSubscriberInterface {
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function getSubscribedEvents() {
+    $events = [];
+    // If the autoloader is not fixed during module install when the modules
+    // module_install_class_loader_test1 and module_install_class_loader_test2
+    // are enabled in the same request the class_exists() will cause a crash.
+    // This is because \Composer\Autoload\ClassLoader maintains a negative
+    // cache.
+    if (class_exists('\Drupal\module_install_class_loader_test2\EventSubscriber')) {
+      $events = [];
+    }
+    return $events;
+  }
+
+}
diff --git a/core/modules/system/tests/modules/module_install_class_loader_test2/module_install_class_loader_test2.info.yml b/core/modules/system/tests/modules/module_install_class_loader_test2/module_install_class_loader_test2.info.yml
new file mode 100644
index 00000000000..5154c9bf06c
--- /dev/null
+++ b/core/modules/system/tests/modules/module_install_class_loader_test2/module_install_class_loader_test2.info.yml
@@ -0,0 +1,8 @@
+name: 'Module install class loader test2'
+description: 'Support module for tests that the class loader behaves as expected during module install.'
+type: module
+package: Testing
+core: 8.x
+version: VERSION
+dependencies:
+  - module_install_class_loader_test1
diff --git a/core/modules/system/tests/modules/module_install_class_loader_test2/module_install_class_loader_test2.services.yml b/core/modules/system/tests/modules/module_install_class_loader_test2/module_install_class_loader_test2.services.yml
new file mode 100644
index 00000000000..7ecca457dfc
--- /dev/null
+++ b/core/modules/system/tests/modules/module_install_class_loader_test2/module_install_class_loader_test2.services.yml
@@ -0,0 +1,5 @@
+services:
+  module_install_class_loader_test1.event_subscriber:
+    class: Drupal\module_install_class_loader_test2\EventSubscriber
+    tags:
+      - { name: event_subscriber }
diff --git a/core/modules/system/tests/modules/module_install_class_loader_test2/src/EventSubscriber.php b/core/modules/system/tests/modules/module_install_class_loader_test2/src/EventSubscriber.php
new file mode 100644
index 00000000000..d994ca3d278
--- /dev/null
+++ b/core/modules/system/tests/modules/module_install_class_loader_test2/src/EventSubscriber.php
@@ -0,0 +1,19 @@
+<?php
+
+namespace Drupal\module_install_class_loader_test2;
+
+use Symfony\Component\EventDispatcher\EventSubscriberInterface;
+
+/**
+ * An event subscriber that does nothing.
+ */
+class EventSubscriber implements EventSubscriberInterface {
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function getSubscribedEvents() {
+    return [];
+  }
+
+}
diff --git a/core/tests/Drupal/Tests/Component/ClassFinder/ClassFinderTest.php b/core/tests/Drupal/Tests/Component/ClassFinder/ClassFinderTest.php
new file mode 100644
index 00000000000..cf1a84b112e
--- /dev/null
+++ b/core/tests/Drupal/Tests/Component/ClassFinder/ClassFinderTest.php
@@ -0,0 +1,39 @@
+<?php
+
+namespace Drupal\Tests\Component\ClassFinder;
+
+use Composer\Autoload\ClassLoader;
+use Drupal\Component\ClassFinder\ClassFinder;
+use Drupal\Tests\UnitTestCase;
+
+/**
+ * @coversDefaultClass \Drupal\Component\ClassFinder\ClassFinder
+ * @group ClassFinder
+ */
+class ClassFinderTest extends UnitTestCase {
+
+  /**
+   * @covers ::findFile
+   */
+  public function testFindFile() {
+    $finder = new ClassFinder();
+
+    // The full path is returned therefore only tests with
+    // assertStringEndsWith() so the test is portable.
+    $this->assertStringEndsWith('core/tests/Drupal/Tests/UnitTestCase.php', $finder->findFile(UnitTestCase::class));
+    $class = 'Not\\A\\Class';
+    $this->assertNull($finder->findFile($class));
+
+    // Register an autoloader that can find this class.
+    $loader = new ClassLoader();
+    $loader->addClassMap([$class => __FILE__]);
+    $loader->register();
+    $this->assertEquals(__FILE__, $finder->findFile($class));
+    // This shouldn't prevent us from finding the original file.
+    $this->assertStringEndsWith('core/tests/Drupal/Tests/UnitTestCase.php', $finder->findFile(UnitTestCase::class));
+
+    // Clean up the additional autoloader after the test.
+    $loader->unregister();
+  }
+
+}