FOS\UserBundle\Document\UserManager::deleteUser PHP Method

    public function deleteUser(UserInterface $user)
    {
        $this->dm->remove($user);
        $this->dm->flush();
    }

 /**
  * @depends testUserNew
  * @depends testUserData
  * @param User $user
  */
 public function testUserDelete(User $user)
 {
     $user = $this->userManager->findUserBy(['username' => $user->getUsername()]);
     $this->userManager->deleteUser($user);
 }