diff -u b/core/modules/image/src/Tests/ImageStylesPathAndUrlTest.php b/core/modules/image/src/Tests/ImageStylesPathAndUrlTest.php
--- b/core/modules/image/src/Tests/ImageStylesPathAndUrlTest.php
+++ b/core/modules/image/src/Tests/ImageStylesPathAndUrlTest.php
@@ -18,23 +18,28 @@
    *
    * @var array
    */
-  public static $modules = array('image', 'image_module_test', 'language');
+  public static $modules = ['image', 'image_module_test', 'language'];
 
   /**
+   * The image style.
+   *
    * @var \Drupal\image\ImageStyleInterface
    */
   protected $style;
 
+  /**
+   * {@inheritdoc}
+   */
   protected function setUp() {
     parent::setUp();
 
     $this->style = ImageStyle::create([
       'name' => 'style_foo',
-      'label' => $this->randomString()
+      'label' => $this->randomString(),
     ]);
     $this->style->save();
 
-    // Create a new language
+    // Create a new language.
     ConfigurableLanguage::createFromLangcode('fr')->save();
   }
 
@@ -83,14 +88,14 @@
   /**
    * Tests an image style URL with the "public://" schema and language prefix.
    */
-  function testImageStyleUrlAndPathPublicLanguage() {
+  public function testImageStyleUrlAndPathPublicLanguage() {
     $this->doImageStyleUrlAndPathTests('public', TRUE, TRUE, 'fr');
   }
 
   /**
    * Tests an image style URL with the "private://" schema and language prefix.
    */
-  function testImageStyleUrlAndPathPrivateLanguage() {
+  public function testImageStyleUrlAndPathPrivateLanguage() {
     $this->doImageStyleUrlAndPathTests('private', TRUE, TRUE, 'fr');
   }
 
@@ -114,7 +119,7 @@
   /**
    * Tests building an image style URL.
    */
-  function doImageStyleUrlAndPathTests($scheme, $clean_url = TRUE, $extra_slash = FALSE, $langcode = FALSE) {
+  public function doImageStyleUrlAndPathTests($scheme, $clean_url = TRUE, $extra_slash = FALSE, $langcode = FALSE) {
     $this->prepareRequestForGenerator($clean_url);
 
     // Make the default scheme neither "public" nor "private" to verify the
@@ -126,7 +131,7 @@
     $status = file_prepare_directory($directory, FILE_CREATE_DIRECTORY);
     $this->assertNotIdentical(FALSE, $status, 'Created the directory for the generated images for the test style.');
 
-    // Override the language to build the URL for the correct language
+    // Override the language to build the URL for the correct language.
     if ($langcode) {
       $language_manager = \Drupal::service('language_manager');
       $language = $language_manager->getLanguage($langcode);
@@ -147,7 +152,7 @@
     $this->assertFalse(file_exists($generated_uri), 'Generated file does not exist.');
     $generate_url = $this->style->buildUrl($original_uri, $clean_url);
 
-    // Make sure that language prefix is never added to the image style URL.q
+    // Make sure that language prefix is never added to the image style URL.
     if ($langcode) {
       $this->assertTrue(strpos($generate_url, "/$langcode/") === FALSE, 'Langcode was not found in the image style URL.');
     }
@@ -226,13 +231,15 @@
 
       $this->drupalGet($generate_url_noaccess);
       $this->assertResponse(403, 'Confirmed that access is denied for the private image style.');
-      // Verify that images are not appended to the response. Currently this test only uses PNG images.
+      // Verify that images are not appended to the response.
+      // Currently this test only uses PNG images.
       if (strpos($generate_url, '.png') === FALSE) {
         $this->fail('Confirming that private image styles are not appended require PNG file.');
       }
       else {
-        // Check for PNG-Signature (cf. http://www.libpng.org/pub/png/book/chapter08.html#png.ch08.div.2) in the
-        // response body.
+        // Check for PNG-Signature
+        // (cf. http://www.libpng.org/pub/png/book/chapter08.html#png.ch08.div.2)
+        // in the response body.
         $this->assertNoRaw(chr(137) . chr(80) . chr(78) . chr(71) . chr(13) . chr(10) . chr(26) . chr(10), 'No PNG signature found in the response body.');
       }
     }