diff --git a/core/modules/simpletest/simpletest.module b/core/modules/simpletest/simpletest.module
index d04012e..947ef26 100644
--- a/core/modules/simpletest/simpletest.module
+++ b/core/modules/simpletest/simpletest.module
@@ -244,6 +244,7 @@ function simpletest_phpunit_run_command(array $unescaped_test_classnames, $phpun
 
   $command = array(
     $phpunit_bin,
+    '--strict',
     '--filter',
     escapeshellarg($filter_string),
     '--log-junit',
diff --git a/core/tests/Drupal/Tests/Core/Extension/ModuleHandlerUnitTest.php b/core/tests/Drupal/Tests/Core/Extension/ModuleHandlerUnitTest.php
index 49ab1f8..0e35bba 100644
--- a/core/tests/Drupal/Tests/Core/Extension/ModuleHandlerUnitTest.php
+++ b/core/tests/Drupal/Tests/Core/Extension/ModuleHandlerUnitTest.php
@@ -40,7 +40,7 @@ function setUp() {
    */
   public function testLoadInclude() {
     // Attepmting to load a file from a non-existent module should return FALSE.
-    $this->assertFalse($this->moduleHandler->loadInclude('foo', 'inc'));
+    $this->moduleHandler->loadInclude('foo', 'inc');
   }
 
 }