test: add missing tests and fix codecov setup

[ivaylonikolov7]

Description:

• adds missing coverage via unit tests
• fix typo of test timeout from 12s to 120s which made some tests flaky
• add a local command to check codecov so we don't have to wait for remote output
• reached 90% code coverage 🙌

Fixes:
#2588

Notes for reviewer:
Reaching more than the current codecov will be a huge pain as we don't have any big files that have a lot of missing lines but more like 60 files each having 30-40 lines of uncovered rows.

Checklist

• Documented (Code comments, README, etc.)
• Tested (unit, integration, etc.)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

see 48 files with indirect coverage changes

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
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[lfdt-bot]

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