public function testRegistryReadOnce()
 {
     // read once must remove the key after reading once
     $r = $this->rm->registryWrite(0, 'once_key', 'name_bln', 'bln', true);
     $this->assertTrue($r, 'registryWrite not successful');
     $r = $this->rm->registryReadOnce(0, 'once_key', 'name_bln', 'bln');
     $this->assertTrue($r, 'registryrReadOnce not successful');
     $r = $this->rm->registryExists(0, 'once_key', 'name_bln', 'bln');
     $this->assertFalse($r, 'registryExists not successful');
 }