Add unit tests for rdbms-crud module

[derek63]

There is a stub for tests of this module, however no actual tests currently exist. Add as necessary to validate functionality and increase code coverage

[luan-cestari]

I will create some test (I dont think the goal is 100% test coverage by now, but if it is, please let me know). I will make unit test cases using mock as the integration tests in the rest-module is responsible to test using the real external components

[jewzaam]

100% coverage shouldn't be a goal for anything! We are comfortable with 65% on lightblue-core and it's actually gotten above 70% now. So, given on specific policy I'd say shooting for 60%+ is reasonable in the short/mid term.

[luan-cestari]

We can use the nemo instance to see the lines needed to be covered
http://nemo.sonarqube.org/dashboard/index/717419
http://nemo.sonarqube.org/drilldown/measures/717419?highlight=line_coverage&metric=uncovered_lines