diff --git a/core/modules/filter/lib/Drupal/filter/Tests/FilterHtmlImageSecureTest.php b/core/modules/filter/lib/Drupal/filter/Tests/FilterHtmlImageSecureTest.php
index d61bfa1..41c96c2 100644
--- a/core/modules/filter/lib/Drupal/filter/Tests/FilterHtmlImageSecureTest.php
+++ b/core/modules/filter/lib/Drupal/filter/Tests/FilterHtmlImageSecureTest.php
@@ -92,6 +92,11 @@ function testImageSource() {
     $test_images = $this->drupalGetTestFiles('image');
     $test_image = $test_images[0]->filename;
 
+    // Put a test image in the files directory with special filename.
+    $special_filename = 'tést fïle nàme.png';
+    $special_image = rawurlencode($special_filename);
+    file_unmanaged_copy($test_images[0]->uri, 'public://' . $special_filename);
+
     // Create a list of test image sources.
     // The keys become the value of the IMG 'src' attribute, the values are the
     // expected filter conversions.
@@ -102,6 +107,8 @@ function testImageSource() {
       $files_path . '/' . $test_image => $files_path . '/' . $test_image,
       $http_base_url . '/' . $public_files_path . '/' . $test_image => $files_path . '/' . $test_image,
       $https_base_url . '/' . $public_files_path . '/' . $test_image => $files_path . '/' . $test_image,
+      $http_base_url . '/' . $public_files_path . '/' . $special_image => $files_path . '/' . $special_image,
+      $https_base_url . '/' . $public_files_path . '/' . $special_image => $files_path . '/' . $special_image,
       $files_path . '/example.png' => $red_x_image,
       'http://example.com/' . $druplicon => $red_x_image,
       'https://example.com/' . $druplicon => $red_x_image,
diff --git a/sites/default/default.settings.php b/sites/default/default.settings.php
old mode 100644
new mode 100755