Improve coverage #17

[ansasaki]

Implemented test cases to improve the coverage.

The issue #17 is tracking the coverage improvement.

[codecov-io]

Codecov Report

Merging #24 into master will increase coverage by 25.06%. The diff coverage is 86%.

@@             Coverage Diff             @@
##           master      #24       +/-   ##
===========================================
+ Coverage   63.79%   88.85%   +25.06%     
===========================================
  Files           2        2               
  Lines         696      700        +4     
  Branches      178      181        +3     
===========================================
+ Hits          444      622      +178     
+ Misses        169       41      -128     
+ Partials       83       37       -46

Impacted Files	Coverage Δ
src/symbol_version/symbol_version.py	88.79% <86%> (+25.2%)	:arrow_up:

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[coveralls]

Pull Request Test Coverage Report for Build 35

• 45 of 50 (90.0%) changed or added relevant lines in 1 file are covered.
• 3 unchanged lines in 1 file lost coverage.
• Overall coverage increased (+18.3%) to 91.063%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/symbol_version/symbol_version.py	45	50	90.0%
<!--	Total:	45	50	90.0%	-->

Files with Coverage Reduction	New Missed Lines	%
src/symbol_version/symbol_version.py	3	91.03%
<!--	Total:	3		-->

Totals
Change from base Build 26:	18.3%
Covered Lines:	659
Relevant Lines:	700

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💛 - Coveralls