You should try NBi available at nbi.codeplex.com
If you compare it to QueryUnit, it's easier to spot the difference between the expected resultset and the result of the test execution (especially with large resultset).
With NBi you can also test the structure of your cube and check that dimensions, hierarchies, measures are avilable. Other features include also the possibility to check your memebers in dimensions/hierrachies.
You can create large test-suite with this tool, on our side we've more than 2000 tests on the structure and the test-suite run without problems.