TST: expand tests for private repos

[hagenw]

Trying to reproduce errors we experience at audeering/audbcards#45 by expanding the functions called for the test cases that have access to the public and private repo.

[codecov]

Codecov Report

Merging #339 (a4d00f1) into main (c564289) will decrease coverage by 1.2%.
The diff coverage is 100.0%.

❗ Current head a4d00f1 differs from pull request most recent head f04e009. Consider uploading reports for the commit f04e009 to get more accurate results

Additional details and impacted files

Files	Coverage Δ
audb/core/api.py	100.0% <100.0%> (ø)

... and 2 files with indirect coverage changes

[hagenw]

No longer needed.