diff --git a/core/drupalci.yml b/core/drupalci.yml
index 6ce07ee7ad..3f85299d47 100644
--- a/core/drupalci.yml
+++ b/core/drupalci.yml
@@ -15,6 +15,10 @@ build:
         sniff-all-files: false
         halt-on-fail: false
     testing:
+      container_command:
+        commands:
+          - "sudo -u www-data /usr/local/bin/composer update mikey179/vfsstream --with-dependencies --no-progress"
+          - "sudo -u www-data /usr/local/bin/composer require typo3/phar-stream-wrapper:dev-master --no-progress"
       # run_tests task is executed several times in order of performance speeds.
       # halt-on-fail can be set on the run_tests tasks in order to fail fast.
       # suppress-deprecations is false in order to be alerted to usages of
diff --git a/core/lib/Drupal/Core/Security/PharExtensionInterceptor.php b/core/lib/Drupal/Core/Security/PharExtensionInterceptor.php
index a13e8ce819..0d8e8e8304 100644
--- a/core/lib/Drupal/Core/Security/PharExtensionInterceptor.php
+++ b/core/lib/Drupal/Core/Security/PharExtensionInterceptor.php
@@ -31,7 +31,7 @@ class PharExtensionInterceptor implements Assertable {
    * @throws \TYPO3\PharStreamWrapper\Exception
    *   Thrown when the file is not allowed to execute.
    */
-  public function assert($path, $command) {
+  public function assert(string $path, string $command): bool {
     if ($this->baseFileContainsPharExtension($path)) {
       return TRUE;
     }