Commit d50ffa1 introduced a breaking change to Filesystem's makePathRelative method.

Previously, running

$fs->makePathRelative('a', 'b');

correctly resulted in ../a/.

After the mentioned commit, running the same code now results in ./, which is clearly not correct.

This case is not covered by the Filesystem tests since they seem to only test absolute paths.

Imho there should either be tests for relative paths or it should be mentioned in the documentation that the makePathRelative method is only for absolute paths (which I don't assume).