refac: missing user or article is reported with a domain not-found error instead of a raw GORM error, and the API answers 404 for it

api/handlers/article/articleHandler.go

@@ -46,7 +46,7 @@ func (h *Handler) GetArticle(w http.ResponseWriter, r *http.Request) {
 	article, err := h.GetUseCase.GetOnlineArticle(uint32(id))
 	if err != nil {
 		if errors.Is(err, domain.ErrArticleNotFound) {
-			http.Error(w, "Article not found", http.StatusNotFound)
+			http.Error(w, apperr.ArticleNotFoundErrorMessage, http.StatusNotFound)
 			return
 		}
 		http.Error(w, "Internal server error", http.StatusInternalServerError)

api/pkg/apperr/messages.go

@@ -3,3 +3,4 @@ package apperr
 const LogsErrorMessage = "Access to the requested resource is forbidden due to incorrect password and/or username."
 const BodyErrorMessage = "The request cannot be processed due to a mismatch in the format of the body."
 const IdUint32ErrorMessage = "The server expects the ID to be in the format of an unsigned 32-bit integer (uint32)."
+const ArticleNotFoundErrorMessage = "Article not found"

features/not_found_errors.feature

@@ -0,0 +1,75 @@
+Feature: Domain not-found errors instead of raw GORM errors
+
+  As the maintainer of RenewCMS
+  I want a missing article or user reported as a domain not-found error
+  So that the API answers 404 for it instead of leaking a raw GORM error as a 500, and so that
+    a caller can rely on errors.Is(err, article.ErrArticleNotFound) or errors.Is(err, user.ErrUserNotFound)
+
+  Background:
+    Given internal/domain/article defines the sentinel article.ErrArticleNotFound
+    And internal/domain/user defines the sentinel user.ErrUserNotFound
+    And ArticleRepository.Get and ArticleRepository.GetByName return article.ErrArticleNotFound, not gorm.ErrRecordNotFound, when no row matches
+    And UserRepository.Get, UserRepository.GetByUsername and UserRepository.GetByEmail return user.ErrUserNotFound, not gorm.ErrRecordNotFound, when no row matches
+    And GET /v1/article/{id} sits behind the jwtauth Verifier and Authenticator group, and requires a valid jwt cookie
+
+  Scenario Outline: The article repository reports a missing article as a domain error
+    Given a repository backed by an in-memory SQLite database containing an article titled "Backyard Renovation Update" with id 1
+    When <method> is called with <input>
+    Then the result is the error article.ErrArticleNotFound
+    And errors.Is(err, gorm.ErrRecordNotFound) is false
+
+    Examples:
+      | method    | input            |
+      | Get       | id 9             |
+      | GetByName | "Unknown Title"  |
+
+  Scenario Outline: The user repository reports a missing user as a domain error
+    Given a repository backed by an in-memory SQLite database containing a user with id 1, username "alice" and email "alice@example.com"
+    When <method> is called with <input>
+    Then the result is the error user.ErrUserNotFound
+    And errors.Is(err, gorm.ErrRecordNotFound) is false
+
+    Examples:
+      | method        | input                |
+      | Get           | id 9                 |
+      | GetByUsername | "bob"                |
+      | GetByEmail    | "bob@example.com"    |
+
+  Scenario: Fetching a nonexistent article answers 404, not 500
+    Given a valid jwt cookie for a user with id 1
+    And the article repository has no article with id 9999
+    When the client sends GET /v1/article/9999 with that cookie
+    Then the response status is 404
+    And the response body is the text "Article not found"
+
+  Scenario: Fetching an offline article still answers 404 with the same message
+    Given a valid jwt cookie for a user with id 1
+    And the article repository contains an article with id 2, is_online false
+    When the client sends GET /v1/article/2 with that cookie
+    Then the response status is 404
+    And the response body is the text "Article not found"
+
+  Scenario: Fetching an online article still answers 200
+    Given a valid jwt cookie for a user with id 1
+    And the article repository contains an article with id 1, is_online true
+    When the client sends GET /v1/article/1 with that cookie
+    Then the response status is 200
+    And the response body is the article's JSON representation
+
+  Scenario: The article route still requires authentication before existence is even checked
+    Given no jwt cookie is sent
+    And the article repository has no article with id 9999
+    When the client sends GET /v1/article/9999 without a cookie
+    Then the response status is 401
+
+  Scenario Outline: Login never reveals whether the username exists
+    Given a user repository containing a user "alice" with password "hunter2example"
+    When the client sends POST /v1/auth/login with username "<username>" and password "<password>"
+    Then the response status is 403
+    And the response body is the text apperr.LogsErrorMessage
+    And no jwt cookie is set
+
+    Examples:
+      | username | password        | case                    |
+      | alice    | wrongpassword12 | existing user, bad pass |
+      | bob      | hunter2example  | unknown username        |

features/not_found_errors.qa.md

@@ -0,0 +1,26 @@
+# QA procedure: not_found_errors
+
+Package: `test` (black-box, alongside the existing `article_test.go` / `user_test.go` / `use_case_baseline_test.go`).
+
+## Setup shared by every case
+1. Call `validator.InitValidator()` once.
+2. Build in-memory fakes for `article.Repository` and `user.Repository` (extend the existing `mockArticleRepo` / `mockUserRepo` patterns in `test/`), updated so that a lookup by an unknown id/name/username/email now returns `article.ErrArticleNotFound` / `user.ErrUserNotFound` instead of `gorm.ErrRecordNotFound` — mirroring the fixed real repositories.
+3. Wire the real use cases (`useCases.NewGetArticleUseCase`, `useCases.NewCreateArticleUseCase` if needed, `useCases.NewGetUserUseCase`, `useCases.NewListUsersUseCase`, `useCases.NewCreateUserUseCase`) over those fakes.
+4. Build `article.NewHandler(...)` and `auth.NewHandler(...)` from those use cases plus a test `jwtauth.New("HS256", []byte("test-secret"), nil)`.
+5. Mount a fresh `chi.NewRouter()` mirroring `api/router.go`: the article handler's routes inside a group wrapped by `jwtauth.Verifier(token)` + `jwtauth.Authenticator(token)`, the auth handler's routes unprotected. No live server.
+
+## Repository-level checks (real persistence repositories, in-memory SQLite, no HTTP)
+6. Open a `gorm.DB` with `sqlite.Open("file:" + t.Name() + "?mode=memory&cache=shared")` (one named in-memory DB per test, so tests never share rows) (the project's `github.com/glebarez/sqlite` driver, never the real `DB_FILE`), and `db.AutoMigrate(&models.Article{})`. Construct a real `persistence.NewArticleRepository(db)`, seed it with an article id 1 via `Create`. Call `Get(9)` directly; assert `errors.Is(err, article.ErrArticleNotFound)` is true and `errors.Is(err, gorm.ErrRecordNotFound)` is false. Repeat for `GetByName("Unknown Title")`. Close the in-memory DB (or let it drop) at the end of the test.
+7. Open a second `gorm.DB` the same way with `db.AutoMigrate(&models.User{})`. Construct a real `persistence.NewUserRepository(db)`, seed it with a user id 1 / username "alice" / email "alice@example.com" via `Create`. Call `Get(9)`, `GetByUsername("bob")`, `GetByEmail("bob@example.com")` directly; assert each returns `user.ErrUserNotFound` and not `gorm.ErrRecordNotFound`.
+
+## HTTP checks (fakes, per the shared setup above)
+8. Mint a valid jwt cookie for user id 1 with the test `jwtauth.JWTAuth` (encode with `token.Encode(map[string]any{"user_id": uint32(1)})` and set it as the `jwt` cookie on the `httptest.NewRequest`).
+9. `GET /v1/article/9999` with that cookie, empty repo id 9999 → assert status `404`, body `"Article not found\n"` (http.Error appends a trailing newline).
+10. `GET /v1/article/2` with that cookie, repo seeded with an offline article id 2 → assert status `404`, body `"Article not found\n"` (regression: unchanged from before this fix).
+11. `GET /v1/article/1` with that cookie, repo seeded with an online article id 1 → assert status `200`, body decodes to the article JSON with id 1.
+12. `GET /v1/article/9999` with **no** cookie → assert status `401` (regression: jwtauth still gates the route).
+13. `POST /v1/auth/login` with `{"username":"alice","password":"wrongpassword12"}` (repo seeded with user "alice"/bcrypt-hashed "hunter2example") → assert status `403`, body equals `apperr.LogsErrorMessage + "\n"`, no `Set-Cookie: jwt=...` header present.
+14. `POST /v1/auth/login` with `{"username":"bob","password":"hunter2example"}` (no such user in the repo) → assert status `403`, **identical** body to step 13, no `Set-Cookie` header — proves the domain-error change didn't turn this into a distinguishable 404/500 and didn't start leaking existence.
+
+## Manual verification (not exercised by the Go test)
+- None. This slice has no SPA-visible behavior and no SMTP involvement; the SPA's article-detail view already treats any non-2xx as "not found" generically (verify only if the SPA has an article-detail page — otherwise skip).

features/use_case_baseline.feature

@@ -40,10 +40,10 @@ Feature: Use case baseline characterization
       | method           | id | outcome                                                                                    |
       | GetArticle       | 1  | the article with id 1                                                                      |
       | GetArticle       | 2  | the article with id 2 (GetArticle does not hide offline articles)                          |
-      | GetArticle       | 9  | the repository's not-found error (gorm.ErrRecordNotFound)                                  |
+      | GetArticle       | 9  | the error article.ErrArticleNotFound                                                       |
       | GetOnlineArticle | 1  | the article with id 1                                                                      |
       | GetOnlineArticle | 2  | the error article.ErrArticleNotFound                                                       |
-      | GetOnlineArticle | 9  | the repository's not-found error (gorm.ErrRecordNotFound), not article.ErrArticleNotFound  |
+      | GetOnlineArticle | 9  | the error article.ErrArticleNotFound                                                       |
 
   Scenario Outline: GetArticleByName delegates verbatim to the repository
     Given an article repository fake containing an article titled "Backyard Renovation Update" with id 1
@@ -53,7 +53,7 @@ Feature: Use case baseline characterization
     Examples:
       | name                       | outcome                                                    |
       | Backyard Renovation Update | the article with id 1                                      |
-      | Unknown Title              | the repository's not-found error (gorm.ErrRecordNotFound)  |
+      | Unknown Title              | the error article.ErrArticleNotFound                       |
 
   Scenario Outline: ListArticles filters by is_online
     Given an article repository fake containing:
@@ -150,11 +150,11 @@ Feature: Use case baseline characterization
     Examples:
       | method            | input             | outcome                                                    |
       | GetUser           | 1                 | the user with id 1                                         |
-      | GetUser           | 9                 | the repository's not-found error (gorm.ErrRecordNotFound)  |
+      | GetUser           | 9                 | the error user.ErrUserNotFound                              |
       | GetUserByUsername | alice             | the user with id 1                                         |
-      | GetUserByUsername | bob               | the repository's not-found error (gorm.ErrRecordNotFound)  |
+      | GetUserByUsername | bob               | the error user.ErrUserNotFound                              |
       | GetUserByEmail    | alice@example.com | the user with id 1                                         |
-      | GetUserByEmail    | bob@example.com   | the repository's not-found error (gorm.ErrRecordNotFound)  |
+      | GetUserByEmail    | bob@example.com   | the error user.ErrUserNotFound                              |
 
   Scenario: ListUsers returns every user in the fake
     Given a user repository fake containing users with ids 1 and 2

internal/domain/user/userDomain.go

@@ -1,9 +1,12 @@
 package user
 
 import (
+	"errors"
 	"time"
 )
 
+var ErrUserNotFound = errors.New("user not found")
+
 type User struct {
 	ID                     uint32    `json:"id"`
 	Username               string    `json:"username"`

internal/infrastructure/persistence/repositories/articleRepository.go

@@ -38,7 +38,7 @@ func (a *ArticleRepository) Get(id uint32) (domain.Article, error) {
 	var article entity.Article
 	err := a.db.Model(&entity.Article{}).Preload("Images").First(&article, id).Error
 	if err != nil {
-		return domain.Article{}, err
+		return domain.Article{}, mapNotFoundErr(err, domain.ErrArticleNotFound)
 	}
 
 	return mappers.ArticleToDomain(article), nil
@@ -48,7 +48,7 @@ func (a *ArticleRepository) GetByName(name string) (domain.Article, error) {
 	var article entity.Article
 	err := a.db.Model(&entity.Article{}).Where("title = ?", name).First(&article).Error
 	if err != nil {
-		return domain.Article{}, err
+		return domain.Article{}, mapNotFoundErr(err, domain.ErrArticleNotFound)
 	}
 
 	return mappers.ArticleToDomain(article), nil

internal/infrastructure/persistence/repositories/notFound.go

@@ -0,0 +1,14 @@
+package persistence
+
+import (
+	"errors"
+
+	"gorm.io/gorm"
+)
+
+func mapNotFoundErr(err error, sentinel error) error {
+	if errors.Is(err, gorm.ErrRecordNotFound) {
+		return sentinel
+	}
+	return err
+}

internal/infrastructure/persistence/repositories/userRepository.go

@@ -21,7 +21,7 @@ func (u *UserRepository) Get(id uint32) (domainUser.User, error) {
 	var localUser entity.User
 	err := u.db.Model(&entity.User{}).First(&localUser, id).Error
 	if err != nil {
-		return domainUser.User{}, err
+		return domainUser.User{}, mapNotFoundErr(err, domainUser.ErrUserNotFound)
 	}
 
 	return mappers.UserToDomain(localUser), nil
@@ -69,7 +69,7 @@ func (u *UserRepository) GetByUsername(username string) (domainUser.User, error)
 	var localUser entity.User
 	err := u.db.Model(&entity.User{}).Where("username = ?", username).First(&localUser).Error
 	if err != nil {
-		return domainUser.User{}, err
+		return domainUser.User{}, mapNotFoundErr(err, domainUser.ErrUserNotFound)
 	}
 
 	return mappers.UserToDomain(localUser), nil
@@ -79,7 +79,7 @@ func (u *UserRepository) GetByEmail(email string) (domainUser.User, error) {
 	var localUser entity.User
 	err := u.db.Model(&entity.User{}).Where("email = ?", email).First(&localUser).Error
 	if err != nil {
-		return domainUser.User{}, err
+		return domainUser.User{}, mapNotFoundErr(err, domainUser.ErrUserNotFound)
 	}
 
 	return mappers.UserToDomain(localUser), nil

test/article_test.go

@@ -55,7 +55,7 @@ func (m *mockArticleRepo) Get(id uint32) (article.Article, error) {
 	}
 	a, ok := m.articles[id]
 	if !ok {
-		return article.Article{}, gorm.ErrRecordNotFound
+		return article.Article{}, article.ErrArticleNotFound
 	}
 	return a, nil
 }
@@ -70,7 +70,7 @@ func (m *mockArticleRepo) GetByName(name string) (article.Article, error) {
 			return a, nil
 		}
 	}
-	return article.Article{}, gorm.ErrRecordNotFound
+	return article.Article{}, article.ErrArticleNotFound
 }
 
 func (m *mockArticleRepo) GetAll() []article.Article {

test/not_found_errors_test.go

@@ -0,0 +1,278 @@
+package test
+
+import (
+	"RenewCMS/api/handlers/article"
+	"RenewCMS/api/handlers/auth"
+	"RenewCMS/api/pkg/apperr"
+	validator "RenewCMS/api/pkg/validator"
+	domainArticle "RenewCMS/internal/domain/article"
+	domainUser "RenewCMS/internal/domain/user"
+	"RenewCMS/internal/infrastructure/persistence/models"
+	persistence "RenewCMS/internal/infrastructure/persistence/repositories"
+	"RenewCMS/internal/infrastructure/useCases"
+	"bytes"
+	"encoding/json"
+	"errors"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/glebarez/sqlite"
+	"github.com/go-chi/chi/v5"
+	"github.com/go-chi/jwtauth/v5"
+	"golang.org/x/crypto/bcrypt"
+	"gorm.io/gorm"
+)
+
+func openInMemoryDb(t *testing.T) *gorm.DB {
+	t.Helper()
+	db, err := gorm.Open(sqlite.Open("file:"+t.Name()+"?mode=memory&cache=shared"), &gorm.Config{})
+	if err != nil {
+		t.Fatalf("failed to open in-memory database: %v", err)
+	}
+	return db
+}
+
+func TestArticleRepositoryReportsMissingArticleAsDomainError(t *testing.T) {
+	db := openInMemoryDb(t)
+	if err := db.AutoMigrate(&models.Article{}); err != nil {
+		t.Fatalf("failed to migrate: %v", err)
+	}
+	repo := persistence.NewArticleRepository(db)
+	if _, err := repo.Create(domainArticle.Article{Title: "Backyard Renovation Update", Body: "Body"}); err != nil {
+		t.Fatalf("failed to seed article: %v", err)
+	}
+
+	t.Run("Get id 9", func(t *testing.T) {
+		_, err := repo.Get(9)
+		if !errors.Is(err, domainArticle.ErrArticleNotFound) {
+			t.Errorf("expected article.ErrArticleNotFound, got %v", err)
+		}
+		if errors.Is(err, gorm.ErrRecordNotFound) {
+			t.Errorf("expected the domain error, not gorm.ErrRecordNotFound")
+		}
+	})
+
+	t.Run("GetByName Unknown Title", func(t *testing.T) {
+		_, err := repo.GetByName("Unknown Title")
+		if !errors.Is(err, domainArticle.ErrArticleNotFound) {
+			t.Errorf("expected article.ErrArticleNotFound, got %v", err)
+		}
+		if errors.Is(err, gorm.ErrRecordNotFound) {
+			t.Errorf("expected the domain error, not gorm.ErrRecordNotFound")
+		}
+	})
+
+	t.Run("Get propagates a non-not-found database error unchanged", func(t *testing.T) {
+		sqlDb, err := db.DB()
+		if err != nil {
+			t.Fatalf("failed to get sql db: %v", err)
+		}
+		if err := sqlDb.Close(); err != nil {
+			t.Fatalf("failed to close db: %v", err)
+		}
+
+		_, err = repo.Get(1)
+		if err == nil {
+			t.Fatal("expected an error, got nil")
+		}
+		if errors.Is(err, domainArticle.ErrArticleNotFound) {
+			t.Errorf("expected a non-not-found error, got domain.ErrArticleNotFound")
+		}
+	})
+}
+
+func TestUserRepositoryReportsMissingUserAsDomainError(t *testing.T) {
+	db := openInMemoryDb(t)
+	if err := db.AutoMigrate(&models.User{}); err != nil {
+		t.Fatalf("failed to migrate: %v", err)
+	}
+	repo := persistence.NewUserRepository(db)
+	if _, err := repo.Create(domainUser.User{Username: "alice", Password: "hunter2example", Email: "alice@example.com", VerificationCode: "code"}); err != nil {
+		t.Fatalf("failed to seed user: %v", err)
+	}
+
+	t.Run("Get id 9", func(t *testing.T) {
+		_, err := repo.Get(9)
+		if !errors.Is(err, domainUser.ErrUserNotFound) {
+			t.Errorf("expected user.ErrUserNotFound, got %v", err)
+		}
+		if errors.Is(err, gorm.ErrRecordNotFound) {
+			t.Errorf("expected the domain error, not gorm.ErrRecordNotFound")
+		}
+	})
+
+	t.Run("GetByUsername bob", func(t *testing.T) {
+		_, err := repo.GetByUsername("bob")
+		if !errors.Is(err, domainUser.ErrUserNotFound) {
+			t.Errorf("expected user.ErrUserNotFound, got %v", err)
+		}
+		if errors.Is(err, gorm.ErrRecordNotFound) {
+			t.Errorf("expected the domain error, not gorm.ErrRecordNotFound")
+		}
+	})
+
+	t.Run("GetByEmail bob@example.com", func(t *testing.T) {
+		_, err := repo.GetByEmail("bob@example.com")
+		if !errors.Is(err, domainUser.ErrUserNotFound) {
+			t.Errorf("expected user.ErrUserNotFound, got %v", err)
+		}
+		if errors.Is(err, gorm.ErrRecordNotFound) {
+			t.Errorf("expected the domain error, not gorm.ErrRecordNotFound")
+		}
+	})
+}
+
+func newNotFoundErrorsRouter(articleRepo *mockArticleRepo, userRepo *mockUserRepo, token *jwtauth.JWTAuth) *chi.Mux {
+	articleHandler := article.NewHandler(
+		useCases.NewCreateArticleUseCase(articleRepo),
+		useCases.NewGetArticleUseCase(articleRepo),
+		useCases.NewListArticlesUseCase(articleRepo),
+		useCases.NewDeleteArticleUseCase(articleRepo),
+	)
+	authHandler := auth.NewHandler(
+		token,
+		useCases.NewGetUserUseCase(userRepo),
+		useCases.NewListUsersUseCase(userRepo),
+		useCases.NewCreateUserUseCase(userRepo),
+	)
+
+	r := chi.NewRouter()
+	r.Route("/v1", func(r chi.Router) {
+		r.Group(func(r chi.Router) {
+			r.Use(jwtauth.Verifier(token))
+			r.Use(jwtauth.Authenticator(token))
+			r.Route("/article", func(r chi.Router) {
+				r.Get("/{id}", articleHandler.GetArticle)
+			})
+		})
+		r.Route("/auth", func(r chi.Router) {
+			r.Post("/login", authHandler.Login)
+		})
+	})
+	return r
+}
+
+func setJwtCookie(t *testing.T, req *http.Request, token *jwtauth.JWTAuth, userId uint32) {
+	t.Helper()
+	_, tokenString, err := token.Encode(map[string]any{"user_id": userId})
+	if err != nil {
+		t.Fatalf("failed to encode jwt: %v", err)
+	}
+	req.AddCookie(&http.Cookie{Name: "jwt", Value: tokenString})
+}
+
+func TestNotFoundErrorsHttp(t *testing.T) {
+	validator.InitValidator()
+	token := jwtauth.New("HS256", []byte("test-secret"), nil)
+
+	newArticleRepo := func() *mockArticleRepo {
+		repo := newMockArticleRepo()
+		repo.articles[1] = domainArticle.Article{ID: 1, Title: "Backyard Renovation Update", IsOnline: true}
+		repo.articles[2] = domainArticle.Article{ID: 2, Title: "Offline Article", IsOnline: false}
+		return repo
+	}
+
+	t.Run("Fetching a nonexistent article answers 404, not 500", func(t *testing.T) {
+		router := newNotFoundErrorsRouter(newArticleRepo(), newMockUserRepo(), token)
+		req := httptest.NewRequest(http.MethodGet, "/v1/article/9999", nil)
+		setJwtCookie(t, req, token, 1)
+		rec := httptest.NewRecorder()
+		router.ServeHTTP(rec, req)
+
+		if rec.Code != http.StatusNotFound {
+			t.Fatalf("expected status 404, got %d", rec.Code)
+		}
+		if rec.Body.String() != apperr.ArticleNotFoundErrorMessage+"\n" {
+			t.Errorf("unexpected body: %q", rec.Body.String())
+		}
+	})
+
+	t.Run("Fetching an offline article still answers 404 with the same message", func(t *testing.T) {
+		router := newNotFoundErrorsRouter(newArticleRepo(), newMockUserRepo(), token)
+		req := httptest.NewRequest(http.MethodGet, "/v1/article/2", nil)
+		setJwtCookie(t, req, token, 1)
+		rec := httptest.NewRecorder()
+		router.ServeHTTP(rec, req)
+
+		if rec.Code != http.StatusNotFound {
+			t.Fatalf("expected status 404, got %d", rec.Code)
+		}
+		if rec.Body.String() != apperr.ArticleNotFoundErrorMessage+"\n" {
+			t.Errorf("unexpected body: %q", rec.Body.String())
+		}
+	})
+
+	t.Run("Fetching an online article still answers 200", func(t *testing.T) {
+		router := newNotFoundErrorsRouter(newArticleRepo(), newMockUserRepo(), token)
+		req := httptest.NewRequest(http.MethodGet, "/v1/article/1", nil)
+		setJwtCookie(t, req, token, 1)
+		rec := httptest.NewRecorder()
+		router.ServeHTTP(rec, req)
+
+		if rec.Code != http.StatusOK {
+			t.Fatalf("expected status 200, got %d", rec.Code)
+		}
+		var got domainArticle.Article
+		if err := json.Unmarshal(rec.Body.Bytes(), &got); err != nil {
+			t.Fatalf("failed to decode response: %v", err)
+		}
+		if got.ID != 1 {
+			t.Errorf("expected article id 1, got %d", got.ID)
+		}
+	})
+
+	t.Run("The article route still requires authentication before existence is even checked", func(t *testing.T) {
+		router := newNotFoundErrorsRouter(newArticleRepo(), newMockUserRepo(), token)
+		req := httptest.NewRequest(http.MethodGet, "/v1/article/9999", nil)
+		rec := httptest.NewRecorder()
+		router.ServeHTTP(rec, req)
+
+		if rec.Code != http.StatusUnauthorized {
+			t.Fatalf("expected status 401, got %d", rec.Code)
+		}
+	})
+
+	newAliceUserRepo := func() *mockUserRepo {
+		repo := newMockUserRepo()
+		hashed, err := bcrypt.GenerateFromPassword([]byte("hunter2example"), 12)
+		if err != nil {
+			t.Fatalf("failed to hash password: %v", err)
+		}
+		repo.users[1] = domainUser.User{ID: 1, Username: "alice", Password: string(hashed)}
+		return repo
+	}
+
+	loginCases := []struct {
+		name     string
+		username string
+		password string
+	}{
+		{"wrong password for existing user", "alice", "wrongpassword12"},
+		{"nonexistent username", "bob", "hunter2example"},
+	}
+
+	for _, tc := range loginCases {
+		t.Run("Login never reveals whether the username exists: "+tc.name, func(t *testing.T) {
+			router := newNotFoundErrorsRouter(newArticleRepo(), newAliceUserRepo(), token)
+			body, err := json.Marshal(map[string]string{"username": tc.username, "password": tc.password})
+			if err != nil {
+				t.Fatalf("failed to marshal body: %v", err)
+			}
+			req := httptest.NewRequest(http.MethodPost, "/v1/auth/login", bytes.NewReader(body))
+			req.Header.Set("Content-Type", "application/json")
+			rec := httptest.NewRecorder()
+			router.ServeHTTP(rec, req)
+
+			if rec.Code != http.StatusForbidden {
+				t.Fatalf("expected status 403, got %d", rec.Code)
+			}
+			if rec.Body.String() != apperr.LogsErrorMessage+"\n" {
+				t.Errorf("unexpected body: %q", rec.Body.String())
+			}
+			if rec.Header().Get("Set-Cookie") != "" {
+				t.Errorf("expected no Set-Cookie header, got %q", rec.Header().Get("Set-Cookie"))
+			}
+		})
+	}
+}

test/use_case_baseline_test.go

@@ -111,8 +111,8 @@ func TestGetArticleAndGetOnlineArticle(t *testing.T) {
 		repo := newRepo()
 		uc := useCases.NewGetArticleUseCase(repo)
 		_, err := uc.GetArticle(9)
-		if !errors.Is(err, gorm.ErrRecordNotFound) {
+		if !errors.Is(err, article.ErrArticleNotFound) {
-			t.Errorf("expected gorm.ErrRecordNotFound, got %v", err)
+			t.Errorf("expected article.ErrArticleNotFound, got %v", err)
 		}
 	})
 
@@ -141,11 +141,8 @@ func TestGetArticleAndGetOnlineArticle(t *testing.T) {
 		repo := newRepo()
 		uc := useCases.NewGetArticleUseCase(repo)
 		_, err := uc.GetOnlineArticle(9)
-		if !errors.Is(err, gorm.ErrRecordNotFound) {
+		if !errors.Is(err, article.ErrArticleNotFound) {
-			t.Errorf("expected gorm.ErrRecordNotFound, got %v", err)
+			t.Errorf("expected article.ErrArticleNotFound, got %v", err)
-		}
-		if errors.Is(err, article.ErrArticleNotFound) {
-			t.Errorf("expected the raw not-found error, not article.ErrArticleNotFound")
 		}
 	})
 }
@@ -173,8 +170,8 @@ func TestGetArticleByNameDelegatesVerbatim(t *testing.T) {
 		repo := newRepo()
 		uc := useCases.NewGetArticleUseCase(repo)
 		_, err := uc.GetArticleByName("Unknown Title")
-		if !errors.Is(err, gorm.ErrRecordNotFound) {
+		if !errors.Is(err, article.ErrArticleNotFound) {
-			t.Errorf("expected gorm.ErrRecordNotFound, got %v", err)
+			t.Errorf("expected article.ErrArticleNotFound, got %v", err)
 		}
 	})
 }
@@ -519,8 +516,8 @@ func TestGetUserReadsByIdUsernameOrEmail(t *testing.T) {
 		repo := newRepo()
 		uc := useCases.NewGetUserUseCase(repo)
 		_, err := uc.GetUser(9)
-		if !errors.Is(err, gorm.ErrRecordNotFound) {
+		if !errors.Is(err, user.ErrUserNotFound) {
-			t.Errorf("expected gorm.ErrRecordNotFound, got %v", err)
+			t.Errorf("expected user.ErrUserNotFound, got %v", err)
 		}
 	})
 
@@ -540,8 +537,8 @@ func TestGetUserReadsByIdUsernameOrEmail(t *testing.T) {
 		repo := newRepo()
 		uc := useCases.NewGetUserUseCase(repo)
 		_, err := uc.GetUserByUsername("bob")
-		if !errors.Is(err, gorm.ErrRecordNotFound) {
+		if !errors.Is(err, user.ErrUserNotFound) {
-			t.Errorf("expected gorm.ErrRecordNotFound, got %v", err)
+			t.Errorf("expected user.ErrUserNotFound, got %v", err)
 		}
 	})
 
@@ -561,8 +558,8 @@ func TestGetUserReadsByIdUsernameOrEmail(t *testing.T) {
 		repo := newRepo()
 		uc := useCases.NewGetUserUseCase(repo)
 		_, err := uc.GetUserByEmail("bob@example.com")
-		if !errors.Is(err, gorm.ErrRecordNotFound) {
+		if !errors.Is(err, user.ErrUserNotFound) {
-			t.Errorf("expected gorm.ErrRecordNotFound, got %v", err)
+			t.Errorf("expected user.ErrUserNotFound, got %v", err)
 		}
 	})
 }

test/user_test.go

@@ -34,7 +34,7 @@ func (m *mockUserRepo) Get(id uint32) (user.User, error) {
 	}
 	u, ok := m.users[id]
 	if !ok {
-		return user.User{}, gorm.ErrRecordNotFound
+		return user.User{}, user.ErrUserNotFound
 	}
 	return u, nil
 }
@@ -49,7 +49,7 @@ func (m *mockUserRepo) GetByUsername(username string) (user.User, error) {
 			return u, nil
 		}
 	}
-	return user.User{}, gorm.ErrRecordNotFound
+	return user.User{}, user.ErrUserNotFound
 }
 
 func (m *mockUserRepo) GetByEmail(email string) (user.User, error) {
@@ -62,7 +62,7 @@ func (m *mockUserRepo) GetByEmail(email string) (user.User, error) {
 			return u, nil
 		}
 	}
-	return user.User{}, gorm.ErrRecordNotFound
+	return user.User{}, user.ErrUserNotFound
 }
 
 func (m *mockUserRepo) GetAll() []user.User {