Add unit test for TensorNetwork module

[Todorbsc]

No description provided.

[mofeing]

Okay, just need to format the code with JuliaFormatter and it would be done.

[jofrevalles]

Do you want to merge this, @mofeing ?

[mofeing]

Not yet. I think @Todorbsc wants to finish some tests more.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 75.09%. Comparing base (5ee9b93) to head (807328b).
Report is 29 commits behind head on master.

❗ Current head 807328b differs from pull request most recent head 2da731d

Please upload reports for the commit 2da731d to get more accurate results.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #152      +/-   ##
==========================================
+ Coverage   68.76%   75.09%   +6.33%     
==========================================
  Files          19       19              
  Lines        1050     1060      +10     
==========================================
+ Hits          722      796      +74     
+ Misses        328      264      -64     

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[Todorbsc]

As long as you have no more suggestions/corrections, it is ready for merge.