How old is it?
When you turn on the ignition, 2nd click before you fire the engine, all the check lights come on. I think there's an ABS light amongst them IIRC.
However all passenger cars after a certain date must have ABS as standard.
Another way to test is hammer down an empty straight road and hit the anchors fairly hard, the ABS normally gives a vibration through the pedal when it activates, although this is much less marked in newer cars than ones made ten years ago, plus you will find yourself not skidding into the hedge if you have ABS.