namespace declare in .d.ts been ignored

[welsea]

I'm using 29.1.2, ts compiler works as expected, and other tests work also fine, only the one works with the .d.ts report error.
I created a repo for this: https://github.com/welsea/test-jest.git
The error message is ReferenceError: R is not defined.

I don't have much experience with Typescript and unit tests, any help will be appreciated. Thanks.
also in stackoverflow