Tests for io_utils and removal of duplicate code

[strickvl]

Tests for the methods inside io_utils and a couple of places where I thought the original source needed small changes.

Found some duplicate code which existed inside fileio as well as in io_utils so I removed it, leaving fileio.py as the canonical place for most of those kinds of functions.

Pre-requisites

Please ensure you have done the following:

• I have read the CONTRIBUTING.md document.
• If my change requires a change to docs, I have updated the documentation accordingly.
• If I have added an integration, I have updated the integrations table and the corresponding website section.
• I have added tests to cover my changes.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Other (add details above)

[fa9r]

Awesome, always happy to get rid of unused/duplicate code 😊

New tests all look good. Only question: what happened to the is_remote tests?

[fa9r]

🚀

[strickvl]

@bcdurak As discussed, I moved things back such that fileio is the core selection of filesystem functions, and io_utils is where everything else lives. I left convert_to_str in fileio on account of circular import issues.

[bcdurak]

@strickvl Looks great! Amazing job with the tests as well!