Add test for backend

## What
Add more tests, we want 80% coverage on .NET code.
We also want summery for the net tests.

## Why
Add more test to .Net code to get a better coverage.

## Definition of done
- Add build test
- All new tests should be successful
- 80% of the net code should be tested
- Summery should be shown
- Test against an api endpoint should always be mocked

Start by locating the .NET code, existing tests, and the build configuration; the issue does not name specific files or test entry points. Add the requested build and API-focused tests with endpoint mocking, measure coverage toward 80%, and ensure a test summary is shown.

Written by the indexing model from the issue text.