I bit the bullet and upgraded my Sky package to include the sports channels for the duration of the Tests. I suppose I could go to the pub or the rugby club to watch it, but then I'd be forced into sociable boozing, and I'm trying to avoid booze at the moment.
You can probably find a dodgy live stream on the internet. I sometimes watch cycling this way, though my internet connection is rubbish so it often doesn't work very well for me.