If you are taking a degree program, it is the institutions responsibility to ensure that you have met all the requirements. If they don't have enough information on equivalence of a different institutions course, the easiest thing for them is to require you retake the sequence.

The way to get around this isn't by taking pretests (which don't mean much) it's by writing the final exams. In some institutions you will be able to do this without (full?) course fees if you are attempting to demonstrate equivalence.