Ok Jeremy. If you only have two wires, a white and a black in the box where the switch is you can tie them together to see if the switch is bad. What you have is called a switch leg. Yes, turn the breaker off first!
The way they have it wired at the light fixture will determine which wire brings power to the switch and which takes it back to the fixture. As far as checking the switch it makes no difference. I normally use the black wire to bring power in and white to send it back to the light.
At the light fixture what color wire is hooked to the black wire of the light? It is possible if you check you will find that a single white wire could be hooked to the black wire there. If it is black to black going to the light then there should be a white wire tied in with a black wire or wires somewhere in the box for the light. Again it makes no difference as far as checking the switch. Just a teaching moment.
In summary, after you turn off the breaker if you only have two wires at the switch tie them together, turn the breaker on and see if the light works. If it does turn the breaker off and change the switch. Sorry I tend to get long winded. Just trying to explain the what and why.