diff --git a/core/modules/file/src/Tests/Views/RelationshipUserFileDataTest.php b/core/modules/file/src/Tests/Views/RelationshipUserFileDataTest.php
index db49ae1..6115e1a 100644
--- a/core/modules/file/src/Tests/Views/RelationshipUserFileDataTest.php
+++ b/core/modules/file/src/Tests/Views/RelationshipUserFileDataTest.php
@@ -67,7 +67,7 @@ public function testViewsHandlerRelationshipUserFileData() {
       'status' => FILE_STATUS_PERMANENT,
     ]);
     $file->enforceIsNew();
-    file_put_contents($file->getFileUri(), file_get_contents('core/modules/simpletest/files/image-1.png'));
+    file_put_contents($file->getFileUri(), file_get_contents('core/tests/fixtures/files/image-1.png'));
     $file->save();
 
     $account = $this->drupalCreateUser();
diff --git a/core/modules/file/tests/src/Kernel/Migrate/d6/MigrateFileTest.php b/core/modules/file/tests/src/Kernel/Migrate/d6/MigrateFileTest.php
index 7e1cff9..65316d0 100644
--- a/core/modules/file/tests/src/Kernel/Migrate/d6/MigrateFileTest.php
+++ b/core/modules/file/tests/src/Kernel/Migrate/d6/MigrateFileTest.php
@@ -91,7 +91,7 @@ public function testFiles() {
     $this->executeMigration('d6_file');
 
     $file = File::load(2);
-    $this->assertIdentical('public://core/modules/simpletest/files/image-2.jpg', $file->getFileUri());
+    $this->assertIdentical('public://core/tests/fixtures/files/image-2.jpg', $file->getFileUri());
 
     // File 7, created in static::migrateDumpAlter(), shares a path with
     // file 5, which means it should be skipped entirely.
diff --git a/core/modules/image/src/Tests/Views/RelationshipUserImageDataTest.php b/core/modules/image/src/Tests/Views/RelationshipUserImageDataTest.php
index f9381d4..979388c 100644
--- a/core/modules/image/src/Tests/Views/RelationshipUserImageDataTest.php
+++ b/core/modules/image/src/Tests/Views/RelationshipUserImageDataTest.php
@@ -67,7 +67,7 @@ public function testViewsHandlerRelationshipUserImageData() {
       'status' => FILE_STATUS_PERMANENT,
     ]);
     $file->enforceIsNew();
-    file_put_contents($file->getFileUri(), file_get_contents('core/modules/simpletest/files/image-1.png'));
+    file_put_contents($file->getFileUri(), file_get_contents('core/tests/fixtures/files/image-1.png'));
     $file->save();
 
     $account = $this->drupalCreateUser();
diff --git a/core/modules/migrate/tests/src/Kernel/process/CopyFileTest.php b/core/modules/migrate/tests/src/Kernel/process/CopyFileTest.php
index 288ebfb..425b625 100644
--- a/core/modules/migrate/tests/src/Kernel/process/CopyFileTest.php
+++ b/core/modules/migrate/tests/src/Kernel/process/CopyFileTest.php
@@ -45,7 +45,7 @@ public function testSuccessfulCopies() {
     $data_sets = [
       // Test a local to local copy.
       [
-        $this->root . '/core/modules/simpletest/files/image-test.jpg',
+        $this->root . '/core/tests/fixtures/files/image-test.jpg',
         'public://file1.jpg'
       ],
       // Test a temporary file using an absolute path.
@@ -56,7 +56,7 @@ public function testSuccessfulCopies() {
       // Test a temporary file using a relative path.
       [
         $file_absolute,
-        'temporary://core/modules/simpletest/files/test.jpg'
+        'temporary://core/tests/fixtures/files/test.jpg'
       ],
     ];
     foreach ($data_sets as $data) {
@@ -93,7 +93,7 @@ public function testSuccessfulMoves() {
       // Test a temporary file using a relative path.
       [
         $file_2_absolute,
-        'temporary://core/modules/simpletest/files/test.jpg'
+        'temporary://core/tests/fixtures/files/test.jpg'
       ],
     ];
     foreach ($data_sets as $data) {
diff --git a/core/modules/migrate_drupal/tests/fixtures/drupal6.php b/core/modules/migrate_drupal/tests/fixtures/drupal6.php
index 347b2f2..2067345 100644
--- a/core/modules/migrate_drupal/tests/fixtures/drupal6.php
+++ b/core/modules/migrate_drupal/tests/fixtures/drupal6.php
@@ -7715,7 +7715,7 @@
   'fid' => '1',
   'uid' => '1',
   'filename' => 'Image1.png',
-  'filepath' => 'core/modules/simpletest/files/image-1.png',
+  'filepath' => 'core/tests/fixtures/files/image-1.png',
   'filemime' => 'image/png',
   'filesize' => '39325',
   'status' => '1',
@@ -7725,7 +7725,7 @@
   'fid' => '2',
   'uid' => '1',
   'filename' => 'Image2.jpg',
-  'filepath' => 'core/modules/simpletest/files/image-2.jpg',
+  'filepath' => 'core/tests/fixtures/files/image-2.jpg',
   'filemime' => 'image/jpeg',
   'filesize' => '1831',
   'status' => '1',
@@ -7735,7 +7735,7 @@
   'fid' => '3',
   'uid' => '1',
   'filename' => 'Image-test.gif',
-  'filepath' => 'core/modules/simpletest/files/image-test.gif',
+  'filepath' => 'core/tests/fixtures/files/image-test.gif',
   'filemime' => 'image/jpeg',
   'filesize' => '183',
   'status' => '1',
@@ -7745,7 +7745,7 @@
   'fid' => '5',
   'uid' => '1',
   'filename' => 'html-1.txt',
-  'filepath' => 'core/modules/simpletest/files/html-1.txt',
+  'filepath' => 'core/tests/fixtures/files/html-1.txt',
   'filemime' => 'text/plain',
   'filesize' => '24',
   'status' => '1',
@@ -31837,8 +31837,8 @@
   'menu_name' => 'navigation',
   'mlid' => '411',
   'plid' => '0',
-  'link_path' => 'core/modules/simpletest/files/imagecache',
-  'router_path' => 'core/modules/simpletest/files/imagecache',
+  'link_path' => 'core/tests/fixtures/files/imagecache',
+  'router_path' => 'core/tests/fixtures/files/imagecache',
   'link_title' => '',
   'options' => 'a:0:{}',
   'module' => 'system',
@@ -39729,7 +39729,7 @@
   'file' => 'sites/all/modules/cck/includes/content.node_form.inc',
 ))
 ->values(array(
-  'path' => 'core/modules/simpletest/files/imagecache',
+  'path' => 'core/tests/fixtures/files/imagecache',
   'load_functions' => '',
   'to_arg_functions' => '',
   'access_callback' => '_imagecache_menu_access_public_files',
@@ -39739,7 +39739,7 @@
   'fit' => '31',
   'number_parts' => '5',
   'tab_parent' => '',
-  'tab_root' => 'core/modules/simpletest/files/imagecache',
+  'tab_root' => 'core/tests/fixtures/files/imagecache',
   'title' => '',
   'title_callback' => 't',
   'title_arguments' => '',
@@ -44575,7 +44575,7 @@
   'status' => '1',
   'timezone' => '3600',
   'language' => 'fr',
-  'picture' => 'core/modules/simpletest/files/image-test.jpg',
+  'picture' => 'core/tests/fixtures/files/image-test.jpg',
   'init' => 'doe@example.com',
   'data' => 'a:2:{s:7:"contact";i:1;s:13:"form_build_id";s:48:"form-qu_DMjE-Vfg01arT5J4VbuBCkOgx_LeySJx4qrPOSuA";}',
   'timezone_name' => 'Europe/Berlin',
@@ -44600,7 +44600,7 @@
   'status' => '1',
   'timezone' => '7200',
   'language' => 'ro',
-  'picture' => 'core/modules/simpletest/files/image-test.png',
+  'picture' => 'core/tests/fixtures/files/image-test.png',
   'init' => 'roe@example.com',
   'data' => 'a:2:{s:7:"contact";i:0;s:13:"form_build_id";s:48:"form-1TxjbL2_1dEHIxEu2Db6OvEsSN1x9ILH1VCgnvsO6LE";}',
   'timezone_name' => 'Europe/Helsinki',
@@ -45539,7 +45539,7 @@
 ))
 ->values(array(
   'name' => 'file_directory_path',
-  'value' => 's:29:"core/modules/simpletest/files";',
+  'value' => 's:25:"core/tests/fixtures/files";',
 ))
 ->values(array(
   'name' => 'file_directory_temp',
diff --git a/core/modules/user/tests/src/Kernel/Migrate/d6/MigrateUserTest.php b/core/modules/user/tests/src/Kernel/Migrate/d6/MigrateUserTest.php
index 9317834..5a677ad 100644
--- a/core/modules/user/tests/src/Kernel/Migrate/d6/MigrateUserTest.php
+++ b/core/modules/user/tests/src/Kernel/Migrate/d6/MigrateUserTest.php
@@ -43,7 +43,7 @@ protected function setUp() {
       'status' => FILE_STATUS_PERMANENT,
     ));
     $file->enforceIsNew();
-    file_put_contents($file->getFileUri(), file_get_contents('core/modules/simpletest/files/image-1.png'));
+    file_put_contents($file->getFileUri(), file_get_contents('core/tests/fixtures/files/image-1.png'));
     $file->save();
 
     $file = File::create(array(
@@ -57,7 +57,7 @@ protected function setUp() {
       'status' => FILE_STATUS_PERMANENT,
     ));
     $file->enforceIsNew();
-    file_put_contents($file->getFileUri(), file_get_contents('core/modules/simpletest/files/image-2.jpg'));
+    file_put_contents($file->getFileUri(), file_get_contents('core/tests/fixtures/files/image-2.jpg'));
     $file->save();
 
     $this->migrateUsers();
diff --git a/core/modules/user/tests/src/Unit/Migrate/d6/UserPictureFileTest.php b/core/modules/user/tests/src/Unit/Migrate/d6/UserPictureFileTest.php
index 6c045ea..e274968 100644
--- a/core/modules/user/tests/src/Unit/Migrate/d6/UserPictureFileTest.php
+++ b/core/modules/user/tests/src/Unit/Migrate/d6/UserPictureFileTest.php
@@ -24,7 +24,7 @@ class UserPictureFileTest extends MigrateSqlSourceTestCase {
   protected $expectedResults = array(
     array(
       'uid' => '2',
-      'picture' => 'core/modules/simpletest/files/image-test.jpg',
+      'picture' => 'core/tests/fixtures/files/image-test.jpg',
     ),
   );
 
@@ -35,7 +35,7 @@ protected function setUp() {
     $this->databaseContents['users'] = array(
       array(
         'uid' => '2',
-        'picture' => 'core/modules/simpletest/files/image-test.jpg',
+        'picture' => 'core/tests/fixtures/files/image-test.jpg',
       ),
       array(
         'uid' => '15',
diff --git a/core/tests/Drupal/KernelTests/Core/File/ScanDirectoryTest.php b/core/tests/Drupal/KernelTests/Core/File/ScanDirectoryTest.php
index 8362c04..ebd3b56 100644
--- a/core/tests/Drupal/KernelTests/Core/File/ScanDirectoryTest.php
+++ b/core/tests/Drupal/KernelTests/Core/File/ScanDirectoryTest.php
@@ -23,11 +23,7 @@ class ScanDirectoryTest extends FileTestBase {
 
   protected function setUp() {
     parent::setUp();
-    // Hardcode the location of the simpletest files as it is already known
-    // and shouldn't change, and we don't yet have a way to retrieve their
-    // location from drupal_get_filename() in a cached way.
-    // @todo Remove as part of https://www.drupal.org/node/2186491
-    $this->path = 'core/modules/simpletest/files';
+    $this->path = 'core/tests/fixtures/files';
   }
 
   /**
diff --git a/core/tests/Drupal/KernelTests/Core/Image/ToolkitGdTest.php b/core/tests/Drupal/KernelTests/Core/Image/ToolkitGdTest.php
index fe36c3d..ba3c0b2 100644
--- a/core/tests/Drupal/KernelTests/Core/Image/ToolkitGdTest.php
+++ b/core/tests/Drupal/KernelTests/Core/Image/ToolkitGdTest.php
@@ -42,7 +42,7 @@ class ToolkitGdTest extends KernelTestBase {
    *
    * @var array
    */
-  public static $modules = array('system', 'simpletest');
+  public static $modules = ['system'];
 
   /**
    * {@inheritdoc}
@@ -275,7 +275,7 @@ function testManipulations() {
     foreach ($files as $file) {
       foreach ($operations as $op => $values) {
         // Load up a fresh image.
-        $image = $this->imageFactory->get(drupal_get_path('module', 'simpletest') . '/files/' . $file);
+        $image = $this->imageFactory->get("core/tests/fixtures/files/$file");
         $toolkit = $image->getToolkit();
         if (!$image->isValid()) {
           $this->fail(SafeMarkup::format('Could not load image %file.', array('%file' => $file)));
@@ -421,14 +421,14 @@ function testManipulations() {
    */
   public function testResourceDestruction() {
     // Test that an Image object going out of scope releases its GD resource.
-    $image = $this->imageFactory->get(drupal_get_path('module', 'simpletest') . '/files/image-test.png');
+    $image = $this->imageFactory->get('core/tests/fixtures/files/image-test.png');
     $res = $image->getToolkit()->getResource();
     $this->assertTrue(is_resource($res), 'Successfully loaded image resource.');
     $image = NULL;
     $this->assertFalse(is_resource($res), 'Image resource was destroyed after losing scope.');
 
     // Test that 'create_new' operation does not leave orphaned GD resources.
-    $image = $this->imageFactory->get(drupal_get_path('module', 'simpletest') . '/files/image-test.png');
+    $image = $this->imageFactory->get('core/tests/fixtures/files/image-test.png');
     $old_res = $image->getToolkit()->getResource();
     // Check if resource has been created successfully.
     $this->assertTrue(is_resource($old_res));
@@ -451,7 +451,7 @@ function testGifTransparentImages() {
     // Test loading an indexed GIF image with transparent color set.
     // Color at top-right pixel should be fully transparent.
     $file = 'image-test-transparent-indexed.gif';
-    $image = $this->imageFactory->get(drupal_get_path('module', 'simpletest') . '/files/' . $file);
+    $image = $this->imageFactory->get("core/tests/fixtures/files/$file");
     $resource = $image->getToolkit()->getResource();
     $color_index = imagecolorat($resource, $image->getWidth() - 1, 0);
     $color = array_values(imagecolorsforindex($resource, $color_index));
@@ -485,14 +485,14 @@ function testGifTransparentImages() {
     // of 6 colors, and setting the transparent color index to 6 (one higher
     // than the largest allowed index), as follows:
     // @code
-    // $image = imagecreatefromgif('core/modules/simpletest/files/image-test.gif');
+    // $image = imagecreatefromgif('core/tests/fixtures/files/image-test.gif');
     // imagecolortransparent($image, 6);
-    // imagegif($image, 'core/modules/simpletest/files/image-test-transparent-out-of-range.gif');
+    // imagegif($image, 'core/tests/fixtures/files/image-test-transparent-out-of-range.gif');
     // @endcode
     // This allows us to test that an image with an out-of-range color index
     // can be loaded correctly.
     $file = 'image-test-transparent-out-of-range.gif';
-    $image = $this->imageFactory->get(drupal_get_path('module', 'simpletest') . '/files/' . $file);
+    $image = $this->imageFactory->get("core/tests/fixtures/files/$file");
     $toolkit = $image->getToolkit();
 
     if (!$image->isValid()) {
@@ -517,7 +517,7 @@ function testMissingOperation() {
     $file = 'image-test.png';
 
     // Load up a fresh image.
-    $image = $this->imageFactory->get(drupal_get_path('module', 'simpletest') . '/files/' . $file);
+    $image = $this->imageFactory->get("core/tests/fixtures/files/$file");
     if (!$image->isValid()) {
       $this->fail(SafeMarkup::format('Could not load image %file.', array('%file' => $file)));
     }
diff --git a/core/tests/Drupal/KernelTests/Core/Installer/InstallerLanguageTest.php b/core/tests/Drupal/KernelTests/Core/Installer/InstallerLanguageTest.php
index 060ee46..f552774 100644
--- a/core/tests/Drupal/KernelTests/Core/Installer/InstallerLanguageTest.php
+++ b/core/tests/Drupal/KernelTests/Core/Installer/InstallerLanguageTest.php
@@ -27,7 +27,7 @@ function testInstallerTranslationFiles() {
 
     // Hardcode the simpletest module location as we don't yet know where it is.
     // @todo Remove as part of https://www.drupal.org/node/2186491
-    $file_translation = new FileTranslation('core/modules/simpletest/files/translations');
+    $file_translation = new FileTranslation('core/tests/fixtures/files/translations');
     foreach ($expected_translation_files as $langcode => $files_expected) {
       $files_found = $file_translation->findTranslationFiles($langcode);
       $this->assertTrue(count($files_found) == count($files_expected), format_string('@count installer languages found.', array('@count' => count($files_expected))));
diff --git a/core/tests/Drupal/Tests/TestFileCreationTrait.php b/core/tests/Drupal/Tests/TestFileCreationTrait.php
index 33d36fb..b9b253c 100644
--- a/core/tests/Drupal/Tests/TestFileCreationTrait.php
+++ b/core/tests/Drupal/Tests/TestFileCreationTrait.php
@@ -68,7 +68,7 @@ protected function getTestFiles($type, $size = NULL) {
       }
 
       // Copy other test files.
-      $original = \Drupal::root() . '/core/tests/fixtures/files';
+      $original = 'core/tests/fixtures/files';
       $files = file_scan_directory($original, '/(html|image|javascript|php|sql)-.*/');
       foreach ($files as $file) {
         file_unmanaged_copy($file->uri, PublicStream::basePath());