If you dream of landing a big angry fish, you have to get the best from your gear.
This is why I've spent hours and hours rigging my gear and hooking it up to the fence, clothesline or whatever that can take the pressure. And then, heave until something breaks!
If it's a knot that has broken, look closely at where it broke, why did it break right there and is there something I can do while tying the knot to make it stronger?
Keep on repeating the process until it is the main line that breaks. It's a lot of effort going into this, but when you're hooked up to your Personal Best you don't want to discover that the knot was one of your Personal Worst!
If your going to test knots, make sure to tie the swivel to something to keep it in position. If you rig breaks on the other side of the swivel, the swivel will come straight back at you like a bullet. You don't want that, trust me!