diff --git a/core/tests/Drupal/Tests/Component/Discovery/YamlDiscoveryTest.php b/core/tests/Drupal/Tests/Component/Discovery/YamlDiscoveryTest.php
index 80b270a..3f86bdf 100644
--- a/core/tests/Drupal/Tests/Component/Discovery/YamlDiscoveryTest.php
+++ b/core/tests/Drupal/Tests/Component/Discovery/YamlDiscoveryTest.php
@@ -9,6 +9,9 @@
 
 use Drupal\Tests\UnitTestCase;
 use Drupal\Component\Discovery\YamlDiscovery;
+use org\bovigo\vfs\vfsStream;
+use org\bovigo\vfs\vfsStreamDirectory;
+use org\bovigo\vfs\vfsStreamWrapper;
 
 /**
  * YamlDiscovery component unit tests.
@@ -19,24 +22,47 @@
 class YamlDiscoveryTest extends UnitTestCase {
 
   /**
+   * The test module base URL.
+   *
+   * @var string
+   */
+  protected $url;
+
+  /**
+   * {@inheritdoc}
+   */
+  public function setUp() {
+    vfsStreamWrapper::register();
+    $root = new vfsStreamDirectory('test_modules');
+    vfsStreamWrapper::setRoot($root);
+    $this->url = vfsStream::url('test_modules');
+  }
+
+  /**
    * Tests the YAML file discovery.
    *
    * @covers ::findAll
    */
   public function testDiscovery() {
-    $base_path = __DIR__ . '/Fixtures';
     // Set up the directories to search.
     $directories = array(
-      'test_1' => $base_path . '/test_1',
-      'test_2' => $base_path . '/test_2',
+      'test_1' => $this->url . '/test_1',
+      'test_2' => $this->url . '/test_2',
       // Use the same directory with a different provider name.
-      'test_3' => $base_path . '/test_2',
+      'test_3' => $this->url . '/test_2',
     );
 
+    foreach ($directories as $provider => $directory) {
+      if (!file_exists($directory)) {
+        mkdir($directory);
+      }
+      file_put_contents($directory . '/' . $provider . '.test.yml', 'name: test');
+    }
+
     $discovery = new YamlDiscovery('test', $directories);
     $data = $discovery->findAll();
 
-    $this->assertEquals(count($data), count($directories));
+    $this->assertCount(3, $data);
     $this->assertArrayHasKey('test_1', $data);
     $this->assertArrayHasKey('test_2', $data);
     $this->assertArrayHasKey('test_3', $data);
@@ -53,16 +79,30 @@ public function testDiscovery() {
    * @covers ::findAll
    */
   public function testImport() {
-    $base_path = __DIR__ . '/Fixtures';
     // Set up the directories to search.
     $directories = array(
-      'test_import' => $base_path . '/test_import',
+      'test_import' => $this->url . '/test_import',
     );
 
+    $directory = $directories['test_import'];
+    mkdir($directory);
+
+    file_put_contents($directory . '/test_import.test.yml', "
+name: test
+imports:
+  - test_import.yml
+    ");
+
+    file_put_contents($directory . '/test_import.yml', "
+# Name should not get overwritten from import.
+name: test_import
+additional: imported
+    ");
+
     $discovery = new YamlDiscovery('test', $directories);
     $data = $discovery->findAll();
 
-    $this->assertEquals(count($data), count($directories));
+    $this->assertCount(1, $data);
     $this->assertArrayHasKey('test_import', $data);
 
     $item = $data['test_import'];
@@ -74,7 +114,5 @@ public function testImport() {
     // Check the new imported key exists.
     $this->assertArrayHasKey('additional', $item);
     $this->assertEquals($item['additional'], 'imported');
-
   }
-
 }