This commit introduces a new test suite for the `DeleteUser` GraphQL mutation in `internal/adapters/graphql/user_mutations_test.go`. The tests cover successful deletion by an admin and by the user themselves, as well as failure cases for invalid permissions, non-existent users, and invalid input.
During the implementation of these tests, an inconsistency in error handling was discovered. The `internal/data/sql` repositories were using a mix of local and domain-level errors. This has been refactored to consistently use the centralized errors defined in the `internal/domain` package. This change improves the robustness and predictability of the data layer.
The following files were modified to standardize error handling:
- internal/data/sql/base_repository.go
- internal/data/sql/book_repository.go
- internal/data/sql/category_repository.go
- internal/data/sql/copyright_repository.go
- internal/data/sql/country_repository.go
- internal/data/sql/edition_repository.go
- internal/data/sql/email_verification_repository.go
- internal/data/sql/password_reset_repository.go
- internal/data/sql/source_repository.go
- internal/data/sql/tag_repository.go
- internal/data/sql/user_profile_repository.go
- internal/data/sql/user_repository.go
- internal/data/sql/user_session_repository.go
- internal/data/sql/work_repository.go
- internal/data/sql/base_repository_test.go
- internal/data/sql/copyright_repository_test.go
