All I can do about this subject is the fact that when you program in a DSL you don´t have to worry about the infrastrutural code (assertions, validations, component technical specificities, etc). This is automatically added by the code generators and represents, according to a common refered statistics, about 60-70% of the final code. At least in the area where I work, CICS/COBOL/DB2 and J2EE integration platform and web services, this percentage is not exagerated.

When you are testing an application generated from a DSL specification typically you only need to concentrate on the functional code, the remaining 40-30%. This a obvious major advantage compared to mainstream programming.