Fix SAS token generation for directory-scoped access

[dmweis]

Directory scoped SAS tokens require signedDirectoryDepth field to work. This adds it as an optional element.

Docs say "The value of the sdd field must be a non-negative integer." so I went with a u32 assuming no one would need a higher directory depth than that. Is that a sensible assumption?

I also added some tests but they aren't particularly inspired so I am happy to change/remove them

Links:
About directory scoped access: https://learn.microsoft.com/en-us/rest/api/storageservices/create-service-sas#service-sas-support-for-directory-scoped-access
Directory depth field: https://learn.microsoft.com/en-us/rest/api/storageservices/create-service-sas#specify-the-directory-depth

[demoray]

Thanks for the contribution! This looks positive.

My only requested change is to use usize rather than u32, in most of the counting results (think Iterator::count or String::len return usize.

[demoray]

As this example uses a constant expire date of 1970-01-08, the signed token result should always be the same. What are your thoughts for just having a const for the expected result?

Otherwise, to address your comment, this could also naively split on &, as the SasToken in the example should not result in a & except as a delim.

[dmweis]

Good idea!

I added both better splitting and an assert against a hardcoded string. This way you get more clear failures if things break but have a wider test too.

If people add more tests later or other things break the hardcoded tests they can remove one or the other

[dmweis]

Thanks for the approve @demoray !
I assume that since it's approved it's just going to be merged later? Or is there something else I need to do?

[demoray]

Thanks for the approve @demoray ! I assume that since it's approved it's just going to be merged later? Or is there something else I need to do?

You didn't need to do anything else. I needed CI to validate the changes, which has been done now.