[Suggest] test files place to same location.

[hg-pyun]

Summary

How about placing the test file and implementation code together? The two codes are separated and there are many files in the folder, so it is inconvenient to see them together.

As-Is

• src
  • sum.ts
• test
  • sum.spec.ts

To-Be

• src
  • sum.ts
  • sum.spec.ts

[ppeeou]

I referenced the lib below and reflected the folder structure
https://github.com/ramda/ramda
https://github.com/ReactiveX/rxjs
https://github.com/axios/axios
https://github.com/socketio/socket.io
...

However, If the test file is not included when deploying, your suggestion also seems to be fine.

{
   "include": ["src/**/*"],
   "exclude": ["node_modules", "**/*.spec.ts"]
}

What do you think? @shine1594