Create Unit tests for Controllers using K8s Fake Client

[bacherfl]

Short abstract

The goal of this issue is to add unit tests for the FeatureFlagConfiguration and FlagSourceConfiguration controllers, using the Kubernetes fake client.

Why

Adding these tests will help to better verify the behavior of the controllers, as opposed to the ginkgo component tests, since with this approach it's possible to check for certain assertions after each invocation of the controller's Reconcile method, and controlling the current state of the relevant resources with the fake kubernetes client.

Functional requirements

• [ ] Create unit tests using the K8s fake client for both controllers

[odubajDT]

Hi, I would like to work on this please :)

[toddbaert]

@odubajDT assigned!