Improved code coverage for CpsDataServiceImpl

- Added (extended) test to cover missed scenarios
- Removed unnecesarry null check from Production code
- Improved error messages in production code
- Removed duplicate test
- Cleaned up existign test somewhat (labels and aligment)

Issue-ID: CPS-475
Signed-off-by: ToineSiebelink <toine.siebelink@est.tech>
Change-Id: I9761ad6d4777a6bcfee4cbe1b876dd39fa218fc8
3 files changed