Where does the current user come from?

The controller reads it from the X-User-Id header and passes it to the service.

What should the tests check?

Check that a document detail is returned for a request user, that title/body/updated date are present, and that a missing document is handled properly.

Team document detailWorkplace case

A real-world situation reported by 박**

Your task

Build the detail API for a team document library. The current user id is passed in a request header, and the user can open a team document to see its title, body, and last-updated date. Complete GET /documents/{id}. Read the current user id from the X-User-Id header. Implement DocumentService.getDocument and add the needed tests.

Ground rules

•Repositories are provided in memory.
•Keep the controller route and X-User-Id header convention as-is.
•Add tests for new or changed behavior.

Not required

•Login or session issuing.
•Document create, update, or delete APIs.
•Organization invites or team member management.

▶About this challenge

Complete a Spring Boot 3 detail API for a team document library. The request header provides the user id, and the response returns the document title, body, and last-updated date.

In work document systems, the same endpoint can show different data depending on the current user. The controller reads request values, while the service owns the lookup rules for the current user and the document. This problem practices that backend flow.

Where does the current user come from?: The controller reads it from the X-User-Id header and passes it to the service.
What should the tests check?: Check that a document detail is returned for a request user, that title/body/updated date are present, and that a missing document is handled properly.