[wip] Add error tests

[tobias-tengler]

No description provided.

[github-actions]

Qodana for .NET

10 new problems were found

Inspection name	Severity	Problems
Redundant nullable warning suppression expression	🔶 Warning	8
Redundant using directive	🔶 Warning	1
Unused parameter (private accessibility)	🔶 Warning	1

💡 Qodana analysis was run in the pull request mode: only the changed files were checked
☁️ View the detailed Qodana report

Contact Qodana team

Contact us at qodana-support@jetbrains.com

• Or via our issue tracker: https://jb.gg/qodana-issue
• Or share your feedback: https://jb.gg/qodana-discussions

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you all sign our Contributor License Agreement before we can accept your contribution.
1 out of 2 committers have signed the CLA.

✅ tobias-tengler
❌ Michael Staib

---

Michael Staib seems not to be a GitHub user. You need a GitHub account to be able to sign the CLA. If you have already a GitHub account, please add the email address used for this commit to your account.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}