Remove redundant test file 'onfire_integration_test.rb'
Remove TODO file as redundant [ci skip]
Remove `ProcEventHandler` as nobody uses it
Merge pull request #107 from kuraga/remove-todo

Remove TODO file as redundant [ci skip]
Merge pull request #106 from kuraga/patch-4

Remove redundant test file 'onfire_integration_test.rb'
Revert "Tests: Refactor the main module test"

This reverts commit b4a97f3fefb54e9f93aa7343668aaed06df41e28
with some modifications.
Merge pull request #120 from kuraga/revert-refactor-apotomo_test

Revert "Tests: Refactor the main module test"
Merge pull request #105 from kuraga/remove-proc-event-handler

Remove `ProcEventHandler` as nobody uses it
Improve EventHandler test and small comments on other