diff --git a/core/modules/user/tests/src/Functional/UserCancelTest.php b/core/modules/user/tests/src/Functional/UserCancelTest.php
index 951ffcf44f..9889cd65bb 100644
--- a/core/modules/user/tests/src/Functional/UserCancelTest.php
+++ b/core/modules/user/tests/src/Functional/UserCancelTest.php
@@ -99,6 +99,23 @@ public function testUserCancelUid1() {
 
     \Drupal::service('module_installer')->install(['views']);
     \Drupal::service('router.builder')->rebuild();
+    // Update uid 1's name and password to we know it.
+    $password = user_password();
+    $account = [
+      'name' => 'user1',
+      'pass' => $this->container->get('password')->hash(trim($password)),
+    ];
+    // We cannot use $account->save() here, because this would result in the
+    // password being hashed again.
+    db_update('users_field_data')
+      ->fields($account)
+      ->condition('uid', 1)
+      ->execute();
+
+    // Reload and log in uid 1.
+    $user_storage->resetCache([1]);
+    $user1 = $user_storage->load(1);
+    $user1->pass_raw = $password;
 
     // Try to cancel uid 1's account with a different user.
     $admin_user = $this->drupalCreateUser(['administer users']);
@@ -110,6 +127,7 @@ public function testUserCancelUid1() {
     $this->drupalPostForm('admin/people', $edit, t('Apply to selected items'));
 
     // Verify that uid 1's account was not cancelled.
+    $user_storage->resetCache([1]);
     $user1 = $user_storage->load(1);
     $this->assertTrue($user1->isActive(), 'User #1 still exists and is not blocked.');
   }