private function mockUserProvider()
{
$user = $this->mockUser();
$provider = $this->getMock('Symfony\\Component\\Security\\Core\\User\\UserProviderInterface', ['loadUserByUsername', 'refreshUser', 'supportsClass']);
$provider->expects($this->any())->method('loadUserByUsername')->willReturnCallback(function ($username) use($user) {
if ('frontend' === $username || 'backend' === $username) {
return $user;
} else {
throw new UsernameNotFoundException();
}
});
return $provider;
}