feat(assert): added AssertDirEmpty and AssertDirNotEmpty. fixes #37

[schambers]

Adds AssertDirEmpty, AssertDirNotEmpty by checking for io.EOF to assert an empty directory or not. This is more efficient than retrieving a slice of the objects in the directory.

I think everything here works, please let me know if I missed anything obvious or this is missing something.

Thank you!

[codecov]

Codecov Report

Merging #52 (acc85e7) into main (9951098) will increase coverage by 0.20%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main      #52      +/-   ##
==========================================
+ Coverage   87.90%   88.10%   +0.20%     
==========================================
  Files          10       10              
  Lines         587      597      +10     
==========================================
+ Hits          516      526      +10     
  Misses         37       37              
  Partials       34       34              

Impacted Files	Coverage Δ
assert.go	98.35% <100.00%> (+0.07%)	⬆️

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[MarvinJWendt]

Hi @schambers, the PR looks good! Could please fix the linting error (you can see it in the changed files view), thanks!

[schambers]

@MarvinJWendt should be all set now! Thanks!

[MarvinJWendt]

There are a couple of small changes that I'd like.
I will merge the PR as soon as they are fixed :)
Thanks for the submission!

[schambers]

Should be all set to go now @MarvinJWendt!

[MarvinJWendt]

LGTM, thanks for the great work!
Could you please resolve the merge conflict?

[schambers]

@MarvinJWendt should be all set now. Conflicts resolved and fixed up the formatting. Thanks!