services/qingstor: Refactor work dir handler with unit tests

[Prnyself]

No description provided.

[codecov]

Codecov Report

Merging #139 into master will increase coverage by 0.18%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #139      +/-   ##
==========================================
+ Coverage   85.15%   85.34%   +0.18%     
==========================================
  Files          12       12              
  Lines         943      955      +12     
==========================================
+ Hits          803      815      +12     
  Misses         87       87              
  Partials       53       53              

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[Xuanwo]

Here is an overview of what got changed by this pull request:

Complexity increasing per file
==============================
- services/qingstor/servicer_test.go  2
- services/qingstor/servicer.go  1
         

Clones added
============
- services/qingstor/servicer_test.go  4
         

Clones removed
==============
+ services/qingstor/storager.go  -2
         

See the complete overview on Codacy