Filestorage: Improve assert coverage and robustness
Filestorage: Improve assert coverage and robustness

Checks that sha256sum is also not undefrined nor null.
Avoids ReferenceError when window is not defined e.g. on NodeJS.

copy/v86,copy/v86,copy/v86,copy/v86,copy/v86,copy/v86,copy/v86