Testing should be considered more seriously

[tiwanari]

I know I am a careless man who makes many bugs but #46 has too many bugs I expected and what made the matter worse, they hadn't been checked for a long time. So, I propose that we think about testing more seriously. Even if old codes somehow work, I think they also need tests to add changes to them.

[tiwanari]

Here is a discussion space. Please share any idea. Thanks.

[tiwanari]

We considered ways of making tests through #46. @Myusak's comments are really helpful to understand how to make tests.