Add a set of functional tests to MIP Convert covering at least the following;
- surface atmos field
- atmos field on pressure levels
- atmos field on model levels
- atmos field on half model levels
- zonal mean atmos field
- land field on soil levels (sdepth)
- ocean surface field
- ocean field on model levels
- zonal mean ocean field
Add a set of functional tests to MIP Convert covering at least the following;