Before this change some of the integration tests were producing this error
panic: runtime error: invalid memory address or nil pointer dereference
This was caused by an `fs.Object` of which the type (`*Object`) was
not `nil`, but the value within was `nil`. These do not compare as
`nil` leading to the panic.
This is a classic Go gotcha: https://go.dev/doc/faq#nil_error
This was easily fixed by changing the type of one function to return
fs.Object instead of *Object.
