diff --git a/core/modules/file/src/Tests/FileManagedFileElementTest.php b/core/modules/file/src/Tests/FileManagedFileElementTest.php
index 0de2ded..5740509 100644
--- a/core/modules/file/src/Tests/FileManagedFileElementTest.php
+++ b/core/modules/file/src/Tests/FileManagedFileElementTest.php
@@ -18,6 +18,18 @@
  *   that aren't related to fields into it.
  */
 class FileManagedFileElementTest extends FileFieldTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp() {
+    parent::setUp();
+
+    // Setup the max filesize to be the same as the post max size, so we can
+    // post a file which let's PHP to exceed its post max size.
+    ini_set('upload_max_filesize', ini_get('post_max_size'));
+  }
+
   /**
    * Tests the managed_file element type.
    */
@@ -113,8 +125,6 @@ function testManagedFile() {
             // Upload a file which exceeds the configured post_max_size limit.
             $post_max_size_ini = ini_get('post_max_size');
             if ($post_max_size_ini) {
-              $this->assertTrue(FALSE, ini_get('post_max_size'));
-              $this->assertTrue(FALSE, ini_get('upload_max_filesize'));
               $post_max_size = Bytes::toInt($post_max_size_ini);
               $big_test_data = str_repeat('a', $post_max_size * 1.1);
               file_put_contents('public://test.dat', $big_test_data);