Enable warning option on the test task
Adjust indentation
Use parentheses for argument of regular expression literal

This commit removes a ruby's warning.

* "ambiguous first argument; put parentheses or even spaces"
Use parentheses for argument of regular expression literal in test

This commit removes a ruby's warning.

* "ambiguous first argument; put parentheses or even spaces"
Use parentheses for rest arguments

This commit removes a ruby's warning.

* "`*' interpreted as argument prefix"
Check @{ivar} definiton before accessing to it

This commit removes a ruby's warning.

* "instance variable @{ivar} not initialized"