Making your code testable

We were looking at getting standard tests fixed and we did. But at the same time we did overlook that fixing them made a pair of our own tests fall over. Do you see?

We have two failing tests and in the same codeunit LookupValue Posting:

• PostSalesOrderWithNoLookupValue
• PostWarehouseShipmentFromSalesOrderWithNoLookupValue

This is their error text:

Microsoft.Dynamics.Nav.Types.Exceptions.NavNCLAssertErrorException: An error was expected inside an ASSERTERROR statement.\   at Microsoft.Dynamics.Nav.Runtime.NavMethodScope.AssertError(Action body)\   at Microsoft.Dynamics.Nav.BusinessApplication.C

Without debugging, this information already tells me a whole story. This is confirmed by the code of the first test method:

procedure PostSalesOrderWithNoLookupValue();
//[FEATURE] LookupValue Posting Sales Document
var
    SalesHeader: Record "Sales Header...