Make the clang report cleaner

This PR:

• Gets rid of deprecated warnings in the test files (They create too much noise in the input, therefore the actual issues are harder to spot)
• Solves some of the 'false negatives'
• Address some issues

Checklist

• Commits have Signed-off-by: with name/author being identical to the commit author
• Code modified for feature
• Test suite updated with functionality tests
• Test suite updated with negative tests
• Documentation updated

Reviewer's checklist:

• Any issues marked for closing are addressed
• There is a test suite reasonably covering new functionality or modifications
• Function naming, parameters, return values, types, etc., are consistent and according to CONTRIBUTING.md
• This feature/change has adequate documentation added
• No obvious mistakes in the code