It should be the same as for normal undergrads or MBA students. There are lots of practice cases out there (check MBB websites and look for case books). The general rule is, that they will normally be business-based (either market-sizing or some kind of 'strategic' problem - often entering a new market). They should not require specific business (or industry) knowledge beyond the basics (profit=revenue-cost, revenue=price x volume, costs are of different types, fixed and variable, what are the types of things a company might do to cut costs or increase revenue etc). The will generally be looking to test (a) basic mathematical literacy and comfort with maths, (b) ability to structure/synthesise and communicate your understanding (c) creativity/ability to learn quickly and (d) interpersonal skills.
Hope this helps
