Fixed failures in test_save

[jesper-friis]

Description

Accept that other files than exactly those tested for may have been created.

Type of change

• Bug fix.
• New feature.
• Documentation update.
• Test update.

Checklist

This checklist can be used as a help for the reviewer.

• Is the code easy to read and understand?
• Are comments for humans to read, not computers to disregard?
• Does a new feature has an accompanying new test (in the CI or unit testing schemes)?
• Has the documentation been updated as necessary?
• Does this close the issue?
• Is the change limited to the issue?
• Are errors handled for all outcomes?
• Does the new feature provide new restrictions on dependencies, and if so is this documented?

Comments

[jesper-friis]

Instead of suggested fixes, make sure that we always work on an empty directory.

[jesper-friis]

Closing since a simpler fix was added in PR #756