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from day one.

// internal/user/repository.go
package user

import (
    "context"
    "errors"

    "gorm.io/gorm"
    "github.com/BounkhongDev/bkgo/contract"
    "github.com/BounkhongDev/bkgo/errs"
)

type repository struct { db contract.ORM }

func NewRepository(db contract.ORM) UserRepository {
    return &repository{db: db}
}

func (r *repository) FindByID(
    ctx context.Context, id string,
) (*User, error) {
    var u User
    err := r.db.Session(ctx).First(&u, "id = ?", id).Error
    if errors.Is(err, gorm.ErrRecordNotFound) {
        return nil, errs.NotFound("user not found")
    }
    return &u, err
}

// internal/user/usecase_test.go
type mockUserRepo struct {
    FindByIDFn func(ctx context.Context, id string) (*user.User, error)
    // ... other methods
}
func (m *mockUserRepo) FindByID(ctx context.Context, id string) (*user.User, error) {
    return m.FindByIDFn(ctx, id)
}

func TestGetByID_NotFound(t *testing.T) {
    repo := &mockUserRepo{
        FindByIDFn: func(ctx context.Context, id string) (*user.User, error) {
            return nil, errs.NotFound("user not found")
        },
    }

    uc := user.NewUserUsecase(repo)
    _, err := uc.GetByID(context.Background(), "missing")

    ae, ok := errs.IsAppError(err)
    if !ok || ae.Status != 404 {
        t.Fatalf("expected 404, got %v", err)
    }
}