public function testPropertiesExist()
{
$o = new \stdClass();
$o->hello = null;
$o->world = null;
$o->{'!'} = null;
$this->assertTrue(Object::propertiesExist($o, 'hello', 'world', '!'));
$this->assertTrue(Object::propertiesExist($o, 'hello', '!'));
$this->assertFalse(Object::propertiesExist($o, 'hello', 'test'));
}
