Grails - How to - Unit test Service that uses params from controller

Answer 1

Are you running your test as a unit or integration test? If it's not already there, try moving it into test/integration and run it from there using

grails test-app integration:

That runs the test within the Grails environment and will give the joda-time plugin the opportunity to do whatever meta programming magic it's doing to create the type conversion to DateTime it looks like you're missing.