Unit Testing in Open Sentencing Aggregator

### Background on the problem the feature will solve/improved user experience
Our code currently lacks unit testing, which is needed for test driven development practices: easy debugging, functional testing, etc.

### Describe the solution you'd like
Provide unit tests for Open Sentencing Aggregator

### Tasks

Description of the development tasks needed to complete this issue, including tests,

### Acceptance Criteria
Standards we believe this issue must reach to be considered complete and ready for a pull request. E.g precisely all the user should be able to do with this update, performance requirements, security requirements, etc as appropriate.