public function testKeepsEncryptionOnEmptyPasswords()
 {
     $member = new Member();
     $member->Password = '******';
     $member->PasswordEncryption = 'sha1_v2.4';
     $member->write();
     $member->Password = '';
     $member->write();
     $this->assertEquals($member->PasswordEncryption, 'sha1_v2.4');
     $result = $member->checkPassword('');
     $this->assertTrue($result->valid());
 }