First, there is no sense in wasting a whole test roll just to test the chemicals. A film clip alone will sufficiently test the chemicals. An exposed test roll can be used to test the camera or to test exposure and development time/temp/agitation parameters but only with chemicals that you know are good, otherwise your test has waaaay too many variables to give useful results.
Clip tests are easy. Just cut off a piece of exposed leader, mix all chemicals to the correct dilutions and temperatures and put the clip of film in the developer with the lights on for the correct amount of time, then dip it in the stop bath and then fix it for the recommended time. Check the density of it compared to previously developed film leaders -- if it is completely clear then either you fixed first or your developer is completely dead. If it is well developed but milky then your fixer is done. If it is thin (light gray rather than black) then either the developer is weak or the time was too short.
You should also test your fixer without developing the film first, just put a clip of undeveloped leader into the fixer and time how long it takes to clear compared to the normal time of about a minute. If it takes over 2 minutes then you need new fixer most likely (or if you have no more fixer then fix for at least 5 minutes to be sure and check the film before you toss the fixer in case you need to fix for even longer in an emergency).
You should really clip test developer every time and fixer too unless you have just mixed it and you know the concentrate/powder was fairly fresh.