Use self explanatory test rather than snapshot testing.

[yujonglee]

Hi. I'm having good time reading code from dooboo-ui.
But I think some test code in dooboo-ui needs improvements.

Is your feature request related to a problem? Please describe.
Quite a lot of test code is not self-explanatory, it's just snapshot testing.

// every test code is almost same as below

testingLib = render(component);

const json = testingLib.toJSON();

expect(json).toMatchSnapshot();

Describe the solution you'd like
I think it might be better if components are tested using assertions in testing-library, context, given.

Describe alternatives you've considered
If there are reasons to stick to snapshot testing(ofcourse there's some situation hard to test without it), I think at least code organizing with context/given, and removing let might be great.

// ex
let props: any;
let component: ReactElement;
let testingLib: RenderAPI;

Additional context
I found article which is similar to my opinion. Maybe it will let you understand my point.

I'm not experienced programmer so maybe there's something I missed. Then please let me know. If you think part of my idea is acceptable, I'll be working on it.

Thanks.

[hyochan]

@yujong-lee Thanks for the great issue! I've learned from you. Yes, your insight is really blazing and I really wish to see your work and refactoring test code.