Provide meaningful unit tests for src/lib/controller/index.ts

[samayer12]

Describe what should be investigated or refactored

index.ts exposes a constructor suffers from poor test-coverage. There are several instances of branching logic in that file that need test coverage.

Create some unit tests that execute some of the varying paths through src/lib/controller/index.ts and make meaningful assertions to aid someone who is digging into future issues with a Journey or E2E test. We'll know we're "done" with this when CodeCov reports a better coverage (say, 60% or greater?) percentage and the corresponding unit tests make meaningful assertions.

Links to any relevant code

Additional context

We noticed a need for better testing in this file as part of #1519.