Compare test data's content generally (#436)
Compare test data's content generally (#436)

Instead of strictly expecting values returned from a store to be `bytes`
instances only in the tests, relax this to anything that supports the
buffer protocol and has the expected content. This makes it possible to
return things like NumPy `memmap` objects and still have the tests work
correctly.

Co-authored-by: Josh Moore <cd55bd8440e0805376df112a94a6d682617a665c@dundee.ac.uk>
zarr-developers/zarr-python