Previously, the assertEquivalentProblems function and functions used by it dealt with results inside Maybe, sometimes then inside IO. These functions have been migrated to the new TestMonad. Instead of using Maybe, any problems with the test are dealt with by failing the test instead.
The assertEquivalentProblems function used to take a list of labelled expressions for comparison purposes. Now that we have an ordering on the AST, this is pointless. Instead we can directly sort the lists by the expressions involved. This simplifies the code a little.
Finally, a bug has been fixed. The mapping between expected and actual columns in the swapColumns' function of translateEquations was being used as a backward mapping, even though it was in fact a forward mapping. So that has also been corrected.
