If the pretest assessment is a MATLAB Code test type, then learners can expand the test to see the underlying assessment test code.
If that code gives away too much, then consider not making that assessment a pretest. If you are not limiting the number of submissions (default behavior in MATLAB Grader), then there is really no value to making any of the tests pretests anyway.
For an example of how to use pretests, consider looking at the "Calculating voltage using Kirchhoff loops" example problem in the Getting Started with MATLAB Grader problem collection.
I do have some concerns with the code you have shown. Perhaps if you can explain what you are trying to do with this code, perhaps there is an opportunity to modify the problem design.
