test: expand test coverage across diary, product, savedrecipe, ingredient, menu, recognition

- Fix locale_test: add TestMain to pre-populate Supported map so zh/es tests pass
- Export pure functions for testability: ResolveWeekStart, MapCuisineSlug (menu + savedrecipe), MergeAndDeduplicate
- Introduce repository interfaces (DiaryRepository, ProductRepository, SavedRecipeRepository, IngredientSearcher) in each handler; NewHandler now accepts interfaces — concrete *Repository still satisfies them
- Add mock files: diary/mocks, product/mocks, savedrecipe/mocks
- Add handler unit tests (no DB) for diary (8), product (8), savedrecipe (8), ingredient (5)
- Add pure-function unit tests: menu/ResolveWeekStart (6), savedrecipe/MapCuisineSlug (5), recognition/MergeAndDeduplicate (6)
- Add repository integration tests (//go:build integration): diary (4), product (6)
- Extend recipe integration tests: GetByID_Found, GetByID_WithTranslation

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/internal/domain/diary/handler.go

@@ -1,6 +1,7 @@
 package diary
 
 import (
+	"context"
 	"encoding/json"
 	"log/slog"
 	"net/http"
@@ -9,13 +10,20 @@ import (
 	"github.com/go-chi/chi/v5"
 )
 
+// DiaryRepository is the data layer interface used by Handler.
+type DiaryRepository interface {
+	ListByDate(ctx context.Context, userID, date string) ([]*Entry, error)
+	Create(ctx context.Context, userID string, req CreateRequest) (*Entry, error)
+	Delete(ctx context.Context, id, userID string) error
+}
+
 // Handler handles diary endpoints.
 type Handler struct {
-	repo *Repository
+	repo DiaryRepository
 }
 
 // NewHandler creates a new Handler.
-func NewHandler(repo *Repository) *Handler {
+func NewHandler(repo DiaryRepository) *Handler {
 	return &Handler{repo: repo}
 }
 

backend/internal/domain/diary/mocks/repository.go

@@ -0,0 +1,26 @@
+package mocks
+
+import (
+	"context"
+
+	"github.com/food-ai/backend/internal/domain/diary"
+)
+
+// MockDiaryRepository is a test double implementing diary.DiaryRepository.
+type MockDiaryRepository struct {
+	ListByDateFn func(ctx context.Context, userID, date string) ([]*diary.Entry, error)
+	CreateFn     func(ctx context.Context, userID string, req diary.CreateRequest) (*diary.Entry, error)
+	DeleteFn     func(ctx context.Context, id, userID string) error
+}
+
+func (m *MockDiaryRepository) ListByDate(ctx context.Context, userID, date string) ([]*diary.Entry, error) {
+	return m.ListByDateFn(ctx, userID, date)
+}
+
+func (m *MockDiaryRepository) Create(ctx context.Context, userID string, req diary.CreateRequest) (*diary.Entry, error) {
+	return m.CreateFn(ctx, userID, req)
+}
+
+func (m *MockDiaryRepository) Delete(ctx context.Context, id, userID string) error {
+	return m.DeleteFn(ctx, id, userID)
+}

backend/internal/domain/ingredient/handler.go

@@ -1,19 +1,25 @@
 package ingredient
 
 import (
+	"context"
 	"encoding/json"
 	"log/slog"
 	"net/http"
 	"strconv"
 )
 
+// IngredientSearcher is the data layer interface used by Handler.
+type IngredientSearcher interface {
+	Search(ctx context.Context, query string, limit int) ([]*IngredientMapping, error)
+}
+
 // Handler handles ingredient HTTP requests.
 type Handler struct {
-	repo *Repository
+	repo IngredientSearcher
 }
 
 // NewHandler creates a new Handler.
-func NewHandler(repo *Repository) *Handler {
+func NewHandler(repo IngredientSearcher) *Handler {
 	return &Handler{repo: repo}
 }
 

backend/internal/domain/menu/handler.go

@@ -84,7 +84,7 @@ func (h *Handler) GetMenu(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	weekStart, err := resolveWeekStart(r.URL.Query().Get("week"))
+	weekStart, err := ResolveWeekStart(r.URL.Query().Get("week"))
 	if err != nil {
 		writeError(w, http.StatusBadRequest, "invalid week parameter, expected YYYY-WNN")
 		return
@@ -120,7 +120,7 @@ func (h *Handler) GenerateMenu(w http.ResponseWriter, r *http.Request) {
 	}
 	_ = json.NewDecoder(r.Body).Decode(&body)
 
-	weekStart, err := resolveWeekStart(body.Week)
+	weekStart, err := ResolveWeekStart(body.Week)
 	if err != nil {
 		writeError(w, http.StatusBadRequest, "invalid week parameter")
 		return
@@ -302,7 +302,7 @@ func (h *Handler) GenerateShoppingList(w http.ResponseWriter, r *http.Request) {
 	}
 	_ = json.NewDecoder(r.Body).Decode(&body)
 
-	weekStart, err := resolveWeekStart(body.Week)
+	weekStart, err := ResolveWeekStart(body.Week)
 	if err != nil {
 		writeError(w, http.StatusBadRequest, "invalid week parameter")
 		return
@@ -342,7 +342,7 @@ func (h *Handler) GetShoppingList(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	weekStart, err := resolveWeekStart(r.URL.Query().Get("week"))
+	weekStart, err := ResolveWeekStart(r.URL.Query().Get("week"))
 	if err != nil {
 		writeError(w, http.StatusBadRequest, "invalid week parameter")
 		return
@@ -392,7 +392,7 @@ func (h *Handler) ToggleShoppingItem(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	weekStart, err := resolveWeekStart(r.URL.Query().Get("week"))
+	weekStart, err := ResolveWeekStart(r.URL.Query().Get("week"))
 	if err != nil {
 		writeError(w, http.StatusBadRequest, "invalid week parameter")
 		return
@@ -477,7 +477,7 @@ func recipeToCreateRequest(r ai.Recipe) dish.CreateRequest {
 	cr := dish.CreateRequest{
 		Name:        r.Title,
 		Description: r.Description,
-		CuisineSlug: mapCuisineSlug(r.Cuisine),
+		CuisineSlug: MapCuisineSlug(r.Cuisine),
 		ImageURL:    r.ImageURL,
 		Difficulty:  r.Difficulty,
 		PrepTimeMin: r.PrepTimeMin,
@@ -507,9 +507,9 @@ func recipeToCreateRequest(r ai.Recipe) dish.CreateRequest {
 	return cr
 }
 
-// mapCuisineSlug maps a free-form cuisine string (from Gemini) to a known slug.
+// MapCuisineSlug maps a free-form cuisine string (from Gemini) to a known slug.
 // Falls back to "other".
-func mapCuisineSlug(cuisine string) string {
+func MapCuisineSlug(cuisine string) string {
 	known := map[string]string{
 		"russian":        "russian",
 		"italian":        "italian",
@@ -538,8 +538,8 @@ func mapCuisineSlug(cuisine string) string {
 	return "other"
 }
 
-// resolveWeekStart parses "YYYY-WNN" or returns current week's Monday.
+// ResolveWeekStart parses "YYYY-WNN" or returns current week's Monday.
-func resolveWeekStart(week string) (string, error) {
+func ResolveWeekStart(week string) (string, error) {
 	if week == "" {
 		return currentWeekStart(), nil
 	}

backend/internal/domain/product/handler.go

@@ -1,6 +1,7 @@
 package product
 
 import (
+	"context"
 	"encoding/json"
 	"errors"
 	"log/slog"
@@ -10,13 +11,22 @@ import (
 	"github.com/go-chi/chi/v5"
 )
 
+// ProductRepository is the data layer interface used by Handler.
+type ProductRepository interface {
+	List(ctx context.Context, userID string) ([]*Product, error)
+	Create(ctx context.Context, userID string, req CreateRequest) (*Product, error)
+	BatchCreate(ctx context.Context, userID string, items []CreateRequest) ([]*Product, error)
+	Update(ctx context.Context, id, userID string, req UpdateRequest) (*Product, error)
+	Delete(ctx context.Context, id, userID string) error
+}
+
 // Handler handles /products HTTP requests.
 type Handler struct {
-	repo *Repository
+	repo ProductRepository
 }
 
 // NewHandler creates a new Handler.
-func NewHandler(repo *Repository) *Handler {
+func NewHandler(repo ProductRepository) *Handler {
 	return &Handler{repo: repo}
 }
 

backend/internal/domain/product/mocks/repository.go

@@ -0,0 +1,36 @@
+package mocks
+
+import (
+	"context"
+
+	"github.com/food-ai/backend/internal/domain/product"
+)
+
+// MockProductRepository is a test double implementing product.ProductRepository.
+type MockProductRepository struct {
+	ListFn        func(ctx context.Context, userID string) ([]*product.Product, error)
+	CreateFn      func(ctx context.Context, userID string, req product.CreateRequest) (*product.Product, error)
+	BatchCreateFn func(ctx context.Context, userID string, items []product.CreateRequest) ([]*product.Product, error)
+	UpdateFn      func(ctx context.Context, id, userID string, req product.UpdateRequest) (*product.Product, error)
+	DeleteFn      func(ctx context.Context, id, userID string) error
+}
+
+func (m *MockProductRepository) List(ctx context.Context, userID string) ([]*product.Product, error) {
+	return m.ListFn(ctx, userID)
+}
+
+func (m *MockProductRepository) Create(ctx context.Context, userID string, req product.CreateRequest) (*product.Product, error) {
+	return m.CreateFn(ctx, userID, req)
+}
+
+func (m *MockProductRepository) BatchCreate(ctx context.Context, userID string, items []product.CreateRequest) ([]*product.Product, error) {
+	return m.BatchCreateFn(ctx, userID, items)
+}
+
+func (m *MockProductRepository) Update(ctx context.Context, id, userID string, req product.UpdateRequest) (*product.Product, error) {
+	return m.UpdateFn(ctx, id, userID, req)
+}
+
+func (m *MockProductRepository) Delete(ctx context.Context, id, userID string) error {
+	return m.DeleteFn(ctx, id, userID)
+}

backend/internal/domain/recognition/handler.go

@@ -134,7 +134,7 @@ func (h *Handler) RecognizeProducts(w http.ResponseWriter, r *http.Request) {
 	}
 	wg.Wait()
 
-	merged := mergeAndDeduplicate(allItems)
+	merged := MergeAndDeduplicate(allItems)
 	enriched := h.enrichItems(r.Context(), merged)
 	writeJSON(w, http.StatusOK, map[string]any{"items": enriched})
 }
@@ -258,9 +258,9 @@ func (h *Handler) saveClassification(ctx context.Context, c *ai.IngredientClassi
 	return saved
 }
 
-// mergeAndDeduplicate combines results from multiple images.
+// MergeAndDeduplicate combines results from multiple images.
 // Items sharing the same name (case-insensitive) have their quantities summed.
-func mergeAndDeduplicate(batches [][]ai.RecognizedItem) []ai.RecognizedItem {
+func MergeAndDeduplicate(batches [][]ai.RecognizedItem) []ai.RecognizedItem {
 	seen := make(map[string]*ai.RecognizedItem)
 	var order []string
 

backend/internal/domain/savedrecipe/handler.go

@@ -1,6 +1,7 @@
 package savedrecipe
 
 import (
+	"context"
 	"encoding/json"
 	"errors"
 	"log/slog"
@@ -12,13 +13,21 @@ import (
 
 const maxBodySize = 1 << 20 // 1 MB
 
+// SavedRecipeRepository is the data layer interface used by Handler.
+type SavedRecipeRepository interface {
+	Save(ctx context.Context, userID string, req SaveRequest) (*UserSavedRecipe, error)
+	List(ctx context.Context, userID string) ([]*UserSavedRecipe, error)
+	GetByID(ctx context.Context, userID, id string) (*UserSavedRecipe, error)
+	Delete(ctx context.Context, userID, id string) error
+}
+
 // Handler handles HTTP requests for saved recipes.
 type Handler struct {
-	repo *Repository
+	repo SavedRecipeRepository
 }
 
 // NewHandler creates a new Handler.
-func NewHandler(repo *Repository) *Handler {
+func NewHandler(repo SavedRecipeRepository) *Handler {
 	return &Handler{repo: repo}
 }
 

backend/internal/domain/savedrecipe/mocks/repository.go

@@ -0,0 +1,31 @@
+package mocks
+
+import (
+	"context"
+
+	"github.com/food-ai/backend/internal/domain/savedrecipe"
+)
+
+// MockSavedRecipeRepository is a test double implementing savedrecipe.SavedRecipeRepository.
+type MockSavedRecipeRepository struct {
+	SaveFn     func(ctx context.Context, userID string, req savedrecipe.SaveRequest) (*savedrecipe.UserSavedRecipe, error)
+	ListFn     func(ctx context.Context, userID string) ([]*savedrecipe.UserSavedRecipe, error)
+	GetByIDFn  func(ctx context.Context, userID, id string) (*savedrecipe.UserSavedRecipe, error)
+	DeleteFn   func(ctx context.Context, userID, id string) error
+}
+
+func (m *MockSavedRecipeRepository) Save(ctx context.Context, userID string, req savedrecipe.SaveRequest) (*savedrecipe.UserSavedRecipe, error) {
+	return m.SaveFn(ctx, userID, req)
+}
+
+func (m *MockSavedRecipeRepository) List(ctx context.Context, userID string) ([]*savedrecipe.UserSavedRecipe, error) {
+	return m.ListFn(ctx, userID)
+}
+
+func (m *MockSavedRecipeRepository) GetByID(ctx context.Context, userID, id string) (*savedrecipe.UserSavedRecipe, error) {
+	return m.GetByIDFn(ctx, userID, id)
+}
+
+func (m *MockSavedRecipeRepository) Delete(ctx context.Context, userID, id string) error {
+	return m.DeleteFn(ctx, userID, id)
+}

backend/internal/domain/savedrecipe/repository.go

@@ -34,7 +34,7 @@ func (r *Repository) Save(ctx context.Context, userID string, req SaveRequest) (
 		cr := dish.CreateRequest{
 			Name:        req.Title,
 			Description: req.Description,
-			CuisineSlug: mapCuisineSlug(req.Cuisine),
+			CuisineSlug: MapCuisineSlug(req.Cuisine),
 			ImageURL:    req.ImageURL,
 			Source:      req.Source,
 			Difficulty:  req.Difficulty,
@@ -373,9 +373,9 @@ func scanUSR(s rowScanner) (*UserSavedRecipe, error) {
 	return &r, err
 }
 
-// mapCuisineSlug maps a free-form cuisine string (from Gemini) to a known slug.
+// MapCuisineSlug maps a free-form cuisine string (from Gemini) to a known slug.
 // Falls back to "other".
-func mapCuisineSlug(cuisine string) string {
+func MapCuisineSlug(cuisine string) string {
 	known := map[string]string{
 		"russian":       "russian",
 		"italian":       "italian",

backend/tests/diary/handler_test.go

@@ -0,0 +1,183 @@
+package diary_test
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+	"time"
+
+	"github.com/food-ai/backend/internal/domain/diary"
+	diarymocks "github.com/food-ai/backend/internal/domain/diary/mocks"
+	"github.com/food-ai/backend/internal/infra/middleware"
+	"github.com/go-chi/chi/v5"
+)
+
+// alwaysAuthValidator injects a fixed user ID via the Auth middleware.
+type alwaysAuthValidator struct{ userID string }
+
+func (v *alwaysAuthValidator) ValidateAccessToken(_ string) (*middleware.TokenClaims, error) {
+	return &middleware.TokenClaims{UserID: v.userID}, nil
+}
+
+// buildRouter wraps handler methods with auth middleware on a chi router.
+func buildRouter(handler *diary.Handler, userID string) *chi.Mux {
+	router := chi.NewRouter()
+	router.Use(middleware.Auth(&alwaysAuthValidator{userID: userID}))
+	router.Get("/diary", handler.GetByDate)
+	router.Post("/diary", handler.Create)
+	router.Delete("/diary/{id}", handler.Delete)
+	return router
+}
+
+func authorizedRequest(method, target string, body []byte) *http.Request {
+	request := httptest.NewRequest(method, target, bytes.NewReader(body))
+	request.Header.Set("Authorization", "Bearer test-token")
+	request.Header.Set("Content-Type", "application/json")
+	return request
+}
+
+func TestGetByDate_MissingQueryParam(t *testing.T) {
+	handler := diary.NewHandler(&diarymocks.MockDiaryRepository{})
+	router := buildRouter(handler, "user-1")
+
+	recorder := httptest.NewRecorder()
+	router.ServeHTTP(recorder, authorizedRequest(http.MethodGet, "/diary", nil))
+
+	if recorder.Code != http.StatusBadRequest {
+		t.Errorf("expected 400, got %d", recorder.Code)
+	}
+}
+
+func TestGetByDate_Success(t *testing.T) {
+	mockRepo := &diarymocks.MockDiaryRepository{
+		ListByDateFn: func(ctx context.Context, userID, date string) ([]*diary.Entry, error) {
+			return []*diary.Entry{
+				{ID: "entry-1", Date: date, MealType: "breakfast", Name: "Oatmeal", Portions: 1},
+			}, nil
+		},
+	}
+	handler := diary.NewHandler(mockRepo)
+	router := buildRouter(handler, "user-1")
+
+	recorder := httptest.NewRecorder()
+	router.ServeHTTP(recorder, authorizedRequest(http.MethodGet, "/diary?date=2026-03-15", nil))
+
+	if recorder.Code != http.StatusOK {
+		t.Errorf("expected 200, got %d", recorder.Code)
+	}
+
+	var entries []diary.Entry
+	if decodeError := json.NewDecoder(recorder.Body).Decode(&entries); decodeError != nil {
+		t.Fatalf("decode response: %v", decodeError)
+	}
+	if len(entries) != 1 {
+		t.Errorf("expected 1 entry, got %d", len(entries))
+	}
+}
+
+func TestCreate_MissingDate(t *testing.T) {
+	handler := diary.NewHandler(&diarymocks.MockDiaryRepository{})
+	router := buildRouter(handler, "user-1")
+
+	body, _ := json.Marshal(map[string]string{"name": "Oatmeal", "meal_type": "breakfast"})
+	recorder := httptest.NewRecorder()
+	router.ServeHTTP(recorder, authorizedRequest(http.MethodPost, "/diary", body))
+
+	if recorder.Code != http.StatusBadRequest {
+		t.Errorf("expected 400, got %d", recorder.Code)
+	}
+}
+
+func TestCreate_MissingName(t *testing.T) {
+	handler := diary.NewHandler(&diarymocks.MockDiaryRepository{})
+	router := buildRouter(handler, "user-1")
+
+	body, _ := json.Marshal(map[string]string{"date": "2026-03-15", "meal_type": "breakfast"})
+	recorder := httptest.NewRecorder()
+	router.ServeHTTP(recorder, authorizedRequest(http.MethodPost, "/diary", body))
+
+	if recorder.Code != http.StatusBadRequest {
+		t.Errorf("expected 400, got %d", recorder.Code)
+	}
+}
+
+func TestCreate_MissingMealType(t *testing.T) {
+	handler := diary.NewHandler(&diarymocks.MockDiaryRepository{})
+	router := buildRouter(handler, "user-1")
+
+	body, _ := json.Marshal(map[string]string{"date": "2026-03-15", "name": "Oatmeal"})
+	recorder := httptest.NewRecorder()
+	router.ServeHTTP(recorder, authorizedRequest(http.MethodPost, "/diary", body))
+
+	if recorder.Code != http.StatusBadRequest {
+		t.Errorf("expected 400, got %d", recorder.Code)
+	}
+}
+
+func TestCreate_Success(t *testing.T) {
+	mockRepo := &diarymocks.MockDiaryRepository{
+		CreateFn: func(ctx context.Context, userID string, req diary.CreateRequest) (*diary.Entry, error) {
+			return &diary.Entry{
+				ID:        "entry-1",
+				Date:      req.Date,
+				MealType:  req.MealType,
+				Name:      req.Name,
+				Portions:  1,
+				Source:    "manual",
+				CreatedAt: time.Now(),
+			}, nil
+		},
+	}
+	handler := diary.NewHandler(mockRepo)
+	router := buildRouter(handler, "user-1")
+
+	body, _ := json.Marshal(diary.CreateRequest{
+		Date:     "2026-03-15",
+		MealType: "breakfast",
+		Name:     "Oatmeal",
+		Portions: 1,
+	})
+	recorder := httptest.NewRecorder()
+	router.ServeHTTP(recorder, authorizedRequest(http.MethodPost, "/diary", body))
+
+	if recorder.Code != http.StatusCreated {
+		t.Errorf("expected 201, got %d", recorder.Code)
+	}
+}
+
+func TestDelete_NotFound(t *testing.T) {
+	mockRepo := &diarymocks.MockDiaryRepository{
+		DeleteFn: func(ctx context.Context, id, userID string) error {
+			return diary.ErrNotFound
+		},
+	}
+	handler := diary.NewHandler(mockRepo)
+	router := buildRouter(handler, "user-1")
+
+	recorder := httptest.NewRecorder()
+	router.ServeHTTP(recorder, authorizedRequest(http.MethodDelete, "/diary/nonexistent-id", nil))
+
+	if recorder.Code != http.StatusNotFound {
+		t.Errorf("expected 404, got %d", recorder.Code)
+	}
+}
+
+func TestDelete_Success(t *testing.T) {
+	mockRepo := &diarymocks.MockDiaryRepository{
+		DeleteFn: func(ctx context.Context, id, userID string) error {
+			return nil
+		},
+	}
+	handler := diary.NewHandler(mockRepo)
+	router := buildRouter(handler, "user-1")
+
+	recorder := httptest.NewRecorder()
+	router.ServeHTTP(recorder, authorizedRequest(http.MethodDelete, "/diary/entry-1", nil))
+
+	if recorder.Code != http.StatusNoContent {
+		t.Errorf("expected 204, got %d", recorder.Code)
+	}
+}

backend/tests/diary/repository_integration_test.go

@@ -0,0 +1,118 @@
+//go:build integration
+
+package diary_test
+
+import (
+	"context"
+	"testing"
+
+	"github.com/food-ai/backend/internal/domain/diary"
+	"github.com/food-ai/backend/internal/testutil"
+)
+
+func TestDiaryRepository_Create_Defaults(t *testing.T) {
+	pool := testutil.SetupTestDB(t)
+	repo := diary.NewRepository(pool)
+	requestContext := context.Background()
+
+	// portions=0 → repository sets 1; source="" → repository sets "manual"
+	entry, createError := repo.Create(requestContext, "test-user", diary.CreateRequest{
+		Date:     "2026-03-15",
+		MealType: "breakfast",
+		Name:     "Oatmeal",
+		Portions: 0,
+		Source:   "",
+	})
+	if createError != nil {
+		t.Fatalf("create diary entry: %v", createError)
+	}
+	if entry.Portions != 1 {
+		t.Errorf("expected portions=1, got %v", entry.Portions)
+	}
+	if entry.Source != "manual" {
+		t.Errorf("expected source=manual, got %q", entry.Source)
+	}
+}
+
+func TestDiaryRepository_ListByDate(t *testing.T) {
+	pool := testutil.SetupTestDB(t)
+	repo := diary.NewRepository(pool)
+	requestContext := context.Background()
+
+	userID := "list-date-user"
+	date := "2026-03-15"
+
+	_, createError := repo.Create(requestContext, userID, diary.CreateRequest{
+		Date: date, MealType: "breakfast", Name: "Oatmeal",
+	})
+	if createError != nil {
+		t.Fatalf("create first entry: %v", createError)
+	}
+	_, createError = repo.Create(requestContext, userID, diary.CreateRequest{
+		Date: date, MealType: "lunch", Name: "Salad",
+	})
+	if createError != nil {
+		t.Fatalf("create second entry: %v", createError)
+	}
+
+	entries, listError := repo.ListByDate(requestContext, userID, date)
+	if listError != nil {
+		t.Fatalf("list by date: %v", listError)
+	}
+	if len(entries) != 2 {
+		t.Errorf("expected 2 entries, got %d", len(entries))
+	}
+}
+
+func TestDiaryRepository_ListByDate_OtherUserNotReturned(t *testing.T) {
+	pool := testutil.SetupTestDB(t)
+	repo := diary.NewRepository(pool)
+	requestContext := context.Background()
+
+	date := "2026-03-15"
+
+	_, createError := repo.Create(requestContext, "user-A", diary.CreateRequest{
+		Date: date, MealType: "breakfast", Name: "Eggs",
+	})
+	if createError != nil {
+		t.Fatalf("create entry for user-A: %v", createError)
+	}
+
+	entries, listError := repo.ListByDate(requestContext, "user-B", date)
+	if listError != nil {
+		t.Fatalf("list by date for user-B: %v", listError)
+	}
+	if len(entries) != 0 {
+		t.Errorf("expected 0 entries for user-B, got %d", len(entries))
+	}
+}
+
+func TestDiaryRepository_Delete_NotFound(t *testing.T) {
+	pool := testutil.SetupTestDB(t)
+	repo := diary.NewRepository(pool)
+	requestContext := context.Background()
+
+	deleteError := repo.Delete(requestContext, "00000000-0000-0000-0000-000000000000", "any-user")
+	if deleteError != diary.ErrNotFound {
+		t.Errorf("expected ErrNotFound, got %v", deleteError)
+	}
+}
+
+func TestDiaryRepository_Delete_WrongUser(t *testing.T) {
+	pool := testutil.SetupTestDB(t)
+	repo := diary.NewRepository(pool)
+	requestContext := context.Background()
+
+	entry, createError := repo.Create(requestContext, "owner-user", diary.CreateRequest{
+		Date: "2026-03-15", MealType: "dinner", Name: "Pasta",
+	})
+	if createError != nil {
+		t.Fatalf("create entry: %v", createError)
+	}
+
+	// Attempt to delete another user's entry — should return ErrNotFound.
+	deleteError := repo.Delete(requestContext, entry.ID, "different-user")
+	if deleteError != diary.ErrNotFound {
+		t.Errorf("expected ErrNotFound when deleting another user's entry, got %v", deleteError)
+	}
+}

backend/tests/ingredient/handler_test.go

@@ -0,0 +1,157 @@
+package ingredient_test
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/food-ai/backend/internal/domain/ingredient"
+	"github.com/food-ai/backend/internal/infra/middleware"
+	"github.com/go-chi/chi/v5"
+)
+
+// mockIngredientSearcher is an inline mock for ingredient.IngredientSearcher.
+type mockIngredientSearcher struct {
+	searchFn func(ctx context.Context, query string, limit int) ([]*ingredient.IngredientMapping, error)
+}
+
+func (m *mockIngredientSearcher) Search(ctx context.Context, query string, limit int) ([]*ingredient.IngredientMapping, error) {
+	return m.searchFn(ctx, query, limit)
+}
+
+type alwaysAuthValidator struct{ userID string }
+
+func (v *alwaysAuthValidator) ValidateAccessToken(_ string) (*middleware.TokenClaims, error) {
+	return &middleware.TokenClaims{UserID: v.userID}, nil
+}
+
+func buildRouter(handler *ingredient.Handler) *chi.Mux {
+	router := chi.NewRouter()
+	router.Use(middleware.Auth(&alwaysAuthValidator{userID: "user-1"}))
+	router.Get("/ingredients/search", handler.Search)
+	return router
+}
+
+func authorizedRequest(target string) *http.Request {
+	request := httptest.NewRequest(http.MethodGet, target, bytes.NewReader(nil))
+	request.Header.Set("Authorization", "Bearer test-token")
+	return request
+}
+
+func TestSearch_EmptyQuery_ReturnsEmptyArray(t *testing.T) {
+	// When q is empty, the handler returns [] without calling the repository.
+	handler := ingredient.NewHandler(&mockIngredientSearcher{})
+	router := buildRouter(handler)
+
+	recorder := httptest.NewRecorder()
+	router.ServeHTTP(recorder, authorizedRequest("/ingredients/search"))
+
+	if recorder.Code != http.StatusOK {
+		t.Errorf("expected 200, got %d", recorder.Code)
+	}
+	if body := recorder.Body.String(); body != "[]" {
+		t.Errorf("expected body [], got %q", body)
+	}
+}
+
+func TestSearch_LimitTooLarge_UsesDefault(t *testing.T) {
+	// When limit > 50, the handler ignores it and uses default 10.
+	calledLimit := 0
+	mockRepo := &mockIngredientSearcher{
+		searchFn: func(ctx context.Context, query string, limit int) ([]*ingredient.IngredientMapping, error) {
+			calledLimit = limit
+			return []*ingredient.IngredientMapping{}, nil
+		},
+	}
+	handler := ingredient.NewHandler(mockRepo)
+	router := buildRouter(handler)
+
+	recorder := httptest.NewRecorder()
+	router.ServeHTTP(recorder, authorizedRequest("/ingredients/search?q=apple&limit=100"))
+
+	if recorder.Code != http.StatusOK {
+		t.Errorf("expected 200, got %d", recorder.Code)
+	}
+	if calledLimit != 10 {
+		t.Errorf("expected repo called with limit=10 (default), got %d", calledLimit)
+	}
+}
+
+func TestSearch_DefaultLimit(t *testing.T) {
+	// When no limit is supplied, the handler uses default 10.
+	calledLimit := 0
+	mockRepo := &mockIngredientSearcher{
+		searchFn: func(ctx context.Context, query string, limit int) ([]*ingredient.IngredientMapping, error) {
+			calledLimit = limit
+			return []*ingredient.IngredientMapping{}, nil
+		},
+	}
+	handler := ingredient.NewHandler(mockRepo)
+	router := buildRouter(handler)
+
+	recorder := httptest.NewRecorder()
+	router.ServeHTTP(recorder, authorizedRequest("/ingredients/search?q=apple"))
+
+	if recorder.Code != http.StatusOK {
+		t.Errorf("expected 200, got %d", recorder.Code)
+	}
+	if calledLimit != 10 {
+		t.Errorf("expected default limit 10, got %d", calledLimit)
+	}
+}
+
+func TestSearch_ValidLimit(t *testing.T) {
+	// limit=25 is within range and should be forwarded as-is.
+	calledLimit := 0
+	mockRepo := &mockIngredientSearcher{
+		searchFn: func(ctx context.Context, query string, limit int) ([]*ingredient.IngredientMapping, error) {
+			calledLimit = limit
+			return []*ingredient.IngredientMapping{}, nil
+		},
+	}
+	handler := ingredient.NewHandler(mockRepo)
+	router := buildRouter(handler)
+
+	recorder := httptest.NewRecorder()
+	router.ServeHTTP(recorder, authorizedRequest("/ingredients/search?q=apple&limit=25"))
+
+	if recorder.Code != http.StatusOK {
+		t.Errorf("expected 200, got %d", recorder.Code)
+	}
+	if calledLimit != 25 {
+		t.Errorf("expected limit 25, got %d", calledLimit)
+	}
+}
+
+func TestSearch_Success(t *testing.T) {
+	mockRepo := &mockIngredientSearcher{
+		searchFn: func(ctx context.Context, query string, limit int) ([]*ingredient.IngredientMapping, error) {
+			return []*ingredient.IngredientMapping{
+				{ID: "ing-1", CanonicalName: "apple"},
+			}, nil
+		},
+	}
+	handler := ingredient.NewHandler(mockRepo)
+	router := buildRouter(handler)
+
+	recorder := httptest.NewRecorder()
+	router.ServeHTTP(recorder, authorizedRequest("/ingredients/search?q=apple"))
+
+	if recorder.Code != http.StatusOK {
+		t.Errorf("expected 200, got %d", recorder.Code)
+	}
+
+	var mappings []ingredient.IngredientMapping
+	if decodeError := json.NewDecoder(recorder.Body).Decode(&mappings); decodeError != nil {
+		t.Fatalf("decode response: %v", decodeError)
+	}
+	if len(mappings) != 1 {
+		t.Errorf("expected 1 result, got %d", len(mappings))
+	}
+	if mappings[0].CanonicalName != "apple" {
+		t.Errorf("expected canonical_name=apple, got %q", mappings[0].CanonicalName)
+	}
+}

backend/tests/locale/locale_test.go

@@ -3,11 +3,21 @@ package locale_test
 import (
 	"context"
 	"net/http"
+	"os"
 	"testing"
 
 	"github.com/food-ai/backend/internal/infra/locale"
 )
 
+func TestMain(m *testing.M) {
+	// Populate Supported map with all known languages before running tests.
+	// In production this is done by locale.LoadFromDB at startup.
+	for _, code := range []string{"en", "ru", "es", "de", "fr", "it", "pt", "zh", "ja", "ko", "ar", "hi"} {
+		locale.Supported[code] = true
+	}
+	os.Exit(m.Run())
+}
+
 func TestParse(t *testing.T) {
 	tests := []struct {
 		name       string

backend/tests/menu/resolve_week_start_test.go

@@ -0,0 +1,61 @@
+package menu_test
+
+import (
+	"testing"
+
+	"github.com/food-ai/backend/internal/domain/menu"
+)
+
+func TestResolveWeekStart_ValidFormat(t *testing.T) {
+	// ISO week 1 of 2026 starts on Monday 2025-12-29
+	result, resolveError := menu.ResolveWeekStart("2026-W01")
+	if resolveError != nil {
+		t.Fatalf("unexpected error: %v", resolveError)
+	}
+	if result != "2025-12-29" {
+		t.Errorf("ResolveWeekStart(2026-W01) = %q, want %q", result, "2025-12-29")
+	}
+}
+
+func TestResolveWeekStart_Week10(t *testing.T) {
+	// Week 10 of 2026 starts on Monday 2026-03-02
+	result, resolveError := menu.ResolveWeekStart("2026-W10")
+	if resolveError != nil {
+		t.Fatalf("unexpected error: %v", resolveError)
+	}
+	if result != "2026-03-02" {
+		t.Errorf("ResolveWeekStart(2026-W10) = %q, want %q", result, "2026-03-02")
+	}
+}
+
+func TestResolveWeekStart_InvalidFormat(t *testing.T) {
+	_, resolveError := menu.ResolveWeekStart("2026-01-05")
+	if resolveError == nil {
+		t.Fatal("expected error for date format input, got nil")
+	}
+}
+
+func TestResolveWeekStart_InvalidWeekNum(t *testing.T) {
+	_, resolveError := menu.ResolveWeekStart("2026-W99")
+	if resolveError == nil {
+		t.Fatal("expected error for week 99, got nil")
+	}
+}
+
+func TestResolveWeekStart_WeekZero(t *testing.T) {
+	_, resolveError := menu.ResolveWeekStart("2026-W00")
+	if resolveError == nil {
+		t.Fatal("expected error for week 0, got nil")
+	}
+}
+
+func TestResolveWeekStart_EmptyReturnsCurrentMonday(t *testing.T) {
+	// Empty string should return current week's Monday without error.
+	result, resolveError := menu.ResolveWeekStart("")
+	if resolveError != nil {
+		t.Fatalf("unexpected error: %v", resolveError)
+	}
+	if len(result) != 10 {
+		t.Errorf("expected date in YYYY-MM-DD format, got %q", result)
+	}
+}

backend/tests/product/handler_test.go

@@ -0,0 +1,200 @@
+package product_test
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+	"time"
+
+	"github.com/food-ai/backend/internal/domain/product"
+	productmocks "github.com/food-ai/backend/internal/domain/product/mocks"
+	"github.com/food-ai/backend/internal/infra/middleware"
+	"github.com/go-chi/chi/v5"
+)
+
+type alwaysAuthValidator struct{ userID string }
+
+func (v *alwaysAuthValidator) ValidateAccessToken(_ string) (*middleware.TokenClaims, error) {
+	return &middleware.TokenClaims{UserID: v.userID}, nil
+}
+
+func buildRouter(handler *product.Handler, userID string) *chi.Mux {
+	router := chi.NewRouter()
+	router.Use(middleware.Auth(&alwaysAuthValidator{userID: userID}))
+	router.Get("/products", handler.List)
+	router.Post("/products", handler.Create)
+	router.Post("/products/batch", handler.BatchCreate)
+	router.Put("/products/{id}", handler.Update)
+	router.Delete("/products/{id}", handler.Delete)
+	return router
+}
+
+func authorizedRequest(method, target string, body []byte) *http.Request {
+	request := httptest.NewRequest(method, target, bytes.NewReader(body))
+	request.Header.Set("Authorization", "Bearer test-token")
+	request.Header.Set("Content-Type", "application/json")
+	return request
+}
+
+func makeProduct(name string) *product.Product {
+	return &product.Product{
+		ID:          "prod-1",
+		UserID:      "user-1",
+		Name:        name,
+		Quantity:    1,
+		Unit:        "pcs",
+		StorageDays: 7,
+		AddedAt:     time.Now(),
+		ExpiresAt:   time.Now().AddDate(0, 0, 7),
+		DaysLeft:    7,
+	}
+}
+
+func TestList_Success(t *testing.T) {
+	mockRepo := &productmocks.MockProductRepository{
+		ListFn: func(ctx context.Context, userID string) ([]*product.Product, error) {
+			return []*product.Product{makeProduct("Milk")}, nil
+		},
+	}
+	handler := product.NewHandler(mockRepo)
+	router := buildRouter(handler, "user-1")
+
+	recorder := httptest.NewRecorder()
+	router.ServeHTTP(recorder, authorizedRequest(http.MethodGet, "/products", nil))
+
+	if recorder.Code != http.StatusOK {
+		t.Errorf("expected 200, got %d", recorder.Code)
+	}
+}
+
+func TestCreate_MissingName(t *testing.T) {
+	handler := product.NewHandler(&productmocks.MockProductRepository{})
+	router := buildRouter(handler, "user-1")
+
+	body, _ := json.Marshal(map[string]any{"quantity": 1})
+	recorder := httptest.NewRecorder()
+	router.ServeHTTP(recorder, authorizedRequest(http.MethodPost, "/products", body))
+
+	if recorder.Code != http.StatusBadRequest {
+		t.Errorf("expected 400, got %d", recorder.Code)
+	}
+}
+
+func TestCreate_Success(t *testing.T) {
+	mockRepo := &productmocks.MockProductRepository{
+		CreateFn: func(ctx context.Context, userID string, req product.CreateRequest) (*product.Product, error) {
+			return makeProduct(req.Name), nil
+		},
+	}
+	handler := product.NewHandler(mockRepo)
+	router := buildRouter(handler, "user-1")
+
+	body, _ := json.Marshal(product.CreateRequest{Name: "Milk", Quantity: 1, Unit: "L"})
+	recorder := httptest.NewRecorder()
+	router.ServeHTTP(recorder, authorizedRequest(http.MethodPost, "/products", body))
+
+	if recorder.Code != http.StatusCreated {
+		t.Errorf("expected 201, got %d", recorder.Code)
+	}
+}
+
+func TestBatchCreate_Success(t *testing.T) {
+	mockRepo := &productmocks.MockProductRepository{
+		BatchCreateFn: func(ctx context.Context, userID string, items []product.CreateRequest) ([]*product.Product, error) {
+			result := make([]*product.Product, len(items))
+			for index, item := range items {
+				result[index] = makeProduct(item.Name)
+			}
+			return result, nil
+		},
+	}
+	handler := product.NewHandler(mockRepo)
+	router := buildRouter(handler, "user-1")
+
+	body, _ := json.Marshal([]product.CreateRequest{
+		{Name: "Milk", Quantity: 1, Unit: "L"},
+		{Name: "Eggs", Quantity: 12, Unit: "pcs"},
+	})
+	recorder := httptest.NewRecorder()
+	router.ServeHTTP(recorder, authorizedRequest(http.MethodPost, "/products/batch", body))
+
+	if recorder.Code != http.StatusCreated {
+		t.Errorf("expected 201, got %d", recorder.Code)
+	}
+}
+
+func TestUpdate_NotFound(t *testing.T) {
+	mockRepo := &productmocks.MockProductRepository{
+		UpdateFn: func(ctx context.Context, id, userID string, req product.UpdateRequest) (*product.Product, error) {
+			return nil, product.ErrNotFound
+		},
+	}
+	handler := product.NewHandler(mockRepo)
+	router := buildRouter(handler, "user-1")
+
+	namePtr := "NewName"
+	body, _ := json.Marshal(product.UpdateRequest{Name: &namePtr})
+	recorder := httptest.NewRecorder()
+	router.ServeHTTP(recorder, authorizedRequest(http.MethodPut, "/products/nonexistent", body))
+
+	if recorder.Code != http.StatusNotFound {
+		t.Errorf("expected 404, got %d", recorder.Code)
+	}
+}
+
+func TestUpdate_Success(t *testing.T) {
+	mockRepo := &productmocks.MockProductRepository{
+		UpdateFn: func(ctx context.Context, id, userID string, req product.UpdateRequest) (*product.Product, error) {
+			updated := makeProduct(*req.Name)
+			return updated, nil
+		},
+	}
+	handler := product.NewHandler(mockRepo)
+	router := buildRouter(handler, "user-1")
+
+	namePtr := "Oat Milk"
+	body, _ := json.Marshal(product.UpdateRequest{Name: &namePtr})
+	recorder := httptest.NewRecorder()
+	router.ServeHTTP(recorder, authorizedRequest(http.MethodPut, "/products/prod-1", body))
+
+	if recorder.Code != http.StatusOK {
+		t.Errorf("expected 200, got %d", recorder.Code)
+	}
+}
+
+func TestDelete_NotFound(t *testing.T) {
+	mockRepo := &productmocks.MockProductRepository{
+		DeleteFn: func(ctx context.Context, id, userID string) error {
+			return product.ErrNotFound
+		},
+	}
+	handler := product.NewHandler(mockRepo)
+	router := buildRouter(handler, "user-1")
+
+	recorder := httptest.NewRecorder()
+	router.ServeHTTP(recorder, authorizedRequest(http.MethodDelete, "/products/nonexistent", nil))
+
+	if recorder.Code != http.StatusNotFound {
+		t.Errorf("expected 404, got %d", recorder.Code)
+	}
+}
+
+func TestDelete_Success(t *testing.T) {
+	mockRepo := &productmocks.MockProductRepository{
+		DeleteFn: func(ctx context.Context, id, userID string) error {
+			return nil
+		},
+	}
+	handler := product.NewHandler(mockRepo)
+	router := buildRouter(handler, "user-1")
+
+	recorder := httptest.NewRecorder()
+	router.ServeHTTP(recorder, authorizedRequest(http.MethodDelete, "/products/prod-1", nil))
+
+	if recorder.Code != http.StatusNoContent {
+		t.Errorf("expected 204, got %d", recorder.Code)
+	}
+}

backend/tests/product/repository_integration_test.go

@@ -0,0 +1,138 @@
+//go:build integration
+
+package product_test
+
+import (
+	"context"
+	"testing"
+
+	"github.com/food-ai/backend/internal/domain/product"
+	"github.com/food-ai/backend/internal/testutil"
+)
+
+func TestProductRepository_Create_Defaults(t *testing.T) {
+	pool := testutil.SetupTestDB(t)
+	repo := product.NewRepository(pool)
+	requestContext := context.Background()
+
+	// storage_days=0 → 7; unit="" → "pcs"; quantity=0 → 1
+	created, createError := repo.Create(requestContext, "test-user", product.CreateRequest{
+		Name:        "Milk",
+		StorageDays: 0,
+		Unit:        "",
+		Quantity:    0,
+	})
+	if createError != nil {
+		t.Fatalf("create product: %v", createError)
+	}
+	if created.StorageDays != 7 {
+		t.Errorf("expected storage_days=7, got %d", created.StorageDays)
+	}
+	if created.Unit != "pcs" {
+		t.Errorf("expected unit=pcs, got %q", created.Unit)
+	}
+	if created.Quantity != 1 {
+		t.Errorf("expected quantity=1, got %v", created.Quantity)
+	}
+}
+
+func TestProductRepository_List_OrderByExpiry(t *testing.T) {
+	pool := testutil.SetupTestDB(t)
+	repo := product.NewRepository(pool)
+	requestContext := context.Background()
+
+	userID := "list-order-user"
+	// Create product with longer expiry first, shorter expiry second.
+	_, createError := repo.Create(requestContext, userID, product.CreateRequest{Name: "Milk", StorageDays: 14})
+	if createError != nil {
+		t.Fatalf("create Milk: %v", createError)
+	}
+	_, createError = repo.Create(requestContext, userID, product.CreateRequest{Name: "Butter", StorageDays: 3})
+	if createError != nil {
+		t.Fatalf("create Butter: %v", createError)
+	}
+
+	products, listError := repo.List(requestContext, userID)
+	if listError != nil {
+		t.Fatalf("list products: %v", listError)
+	}
+	if len(products) != 2 {
+		t.Fatalf("expected 2 products, got %d", len(products))
+	}
+	// Butter (3 days) should come before Milk (14 days).
+	if products[0].Name != "Butter" {
+		t.Errorf("expected first product Butter (expires sooner), got %q", products[0].Name)
+	}
+}
+
+func TestProductRepository_BatchCreate(t *testing.T) {
+	pool := testutil.SetupTestDB(t)
+	repo := product.NewRepository(pool)
+	requestContext := context.Background()
+
+	products, batchError := repo.BatchCreate(requestContext, "batch-user", []product.CreateRequest{
+		{Name: "Eggs", Quantity: 12, Unit: "pcs"},
+		{Name: "Flour", Quantity: 500, Unit: "g"},
+	})
+	if batchError != nil {
+		t.Fatalf("batch create: %v", batchError)
+	}
+	if len(products) != 2 {
+		t.Errorf("expected 2 products, got %d", len(products))
+	}
+}
+
+func TestProductRepository_Update_NotFound(t *testing.T) {
+	pool := testutil.SetupTestDB(t)
+	repo := product.NewRepository(pool)
+	requestContext := context.Background()
+
+	newName := "Ghost"
+	_, updateError := repo.Update(requestContext, "00000000-0000-0000-0000-000000000000", "any-user",
+		product.UpdateRequest{Name: &newName})
+	if updateError != product.ErrNotFound {
+		t.Errorf("expected ErrNotFound, got %v", updateError)
+	}
+}
+
+func TestProductRepository_Delete_WrongUser(t *testing.T) {
+	pool := testutil.SetupTestDB(t)
+	repo := product.NewRepository(pool)
+	requestContext := context.Background()
+
+	created, createError := repo.Create(requestContext, "owner-user", product.CreateRequest{Name: "Cheese"})
+	if createError != nil {
+		t.Fatalf("create product: %v", createError)
+	}
+
+	deleteError := repo.Delete(requestContext, created.ID, "other-user")
+	if deleteError != product.ErrNotFound {
+		t.Errorf("expected ErrNotFound when deleting another user's product, got %v", deleteError)
+	}
+}
+
+func TestProductRepository_ListForPrompt(t *testing.T) {
+	pool := testutil.SetupTestDB(t)
+	repo := product.NewRepository(pool)
+	requestContext := context.Background()
+
+	userID := "prompt-user"
+	_, createError := repo.Create(requestContext, userID, product.CreateRequest{
+		Name: "Tomatoes", Quantity: 4, Unit: "pcs", StorageDays: 5,
+	})
+	if createError != nil {
+		t.Fatalf("create product: %v", createError)
+	}
+
+	lines, listError := repo.ListForPrompt(requestContext, userID)
+	if listError != nil {
+		t.Fatalf("list for prompt: %v", listError)
+	}
+	if len(lines) != 1 {
+		t.Fatalf("expected 1 line, got %d", len(lines))
+	}
+	// Line should start with "- Tomatoes".
+	if len(lines[0]) < 11 || lines[0][:11] != "- Tomatoes " {
+		t.Errorf("unexpected prompt line format: %q", lines[0])
+	}
+}

backend/tests/recipe/repository_integration_test.go

@@ -6,16 +6,18 @@ import (
 	"context"
 	"testing"
 
+	"github.com/food-ai/backend/internal/domain/dish"
 	"github.com/food-ai/backend/internal/domain/recipe"
+	"github.com/food-ai/backend/internal/infra/locale"
 	"github.com/food-ai/backend/internal/testutil"
 )
 
 func TestRecipeRepository_GetByID_NotFound(t *testing.T) {
 	pool := testutil.SetupTestDB(t)
 	repo := recipe.NewRepository(pool)
-	ctx := context.Background()
+	requestContext := context.Background()
 
-	got, getError := repo.GetByID(ctx, "00000000-0000-0000-0000-000000000000")
+	got, getError := repo.GetByID(requestContext, "00000000-0000-0000-0000-000000000000")
 	if getError != nil {
 		t.Fatalf("unexpected error: %v", getError)
 	}
@@ -27,10 +29,92 @@ func TestRecipeRepository_GetByID_NotFound(t *testing.T) {
 func TestRecipeRepository_Count(t *testing.T) {
 	pool := testutil.SetupTestDB(t)
 	repo := recipe.NewRepository(pool)
-	ctx := context.Background()
+	requestContext := context.Background()
 
-	_, countError := repo.Count(ctx)
+	_, countError := repo.Count(requestContext)
 	if countError != nil {
 		t.Fatalf("count: %v", countError)
 	}
 }
+
+func TestRecipeRepository_GetByID_Found(t *testing.T) {
+	pool := testutil.SetupTestDB(t)
+	dishRepo := dish.NewRepository(pool)
+	recipeRepo := recipe.NewRepository(pool)
+	requestContext := context.Background()
+
+	recipeID, createError := dishRepo.Create(requestContext, dish.CreateRequest{
+		Name:        "Test Pasta",
+		Description: "A simple pasta dish",
+		Source:      "test",
+		Ingredients: []dish.IngredientInput{
+			{Name: "pasta", Amount: 200, Unit: "g"},
+		},
+		Steps: []dish.StepInput{
+			{Number: 1, Description: "Boil water"},
+		},
+	})
+	if createError != nil {
+		t.Fatalf("create dish+recipe: %v", createError)
+	}
+
+	found, getError := recipeRepo.GetByID(requestContext, recipeID)
+	if getError != nil {
+		t.Fatalf("get recipe: %v", getError)
+	}
+	if found == nil {
+		t.Fatal("expected recipe to be found, got nil")
+	}
+	if found.ID != recipeID {
+		t.Errorf("expected ID %q, got %q", recipeID, found.ID)
+	}
+	if len(found.Ingredients) != 1 {
+		t.Errorf("expected 1 ingredient, got %d", len(found.Ingredients))
+	}
+	if found.Ingredients[0].Name != "pasta" {
+		t.Errorf("expected ingredient name 'pasta', got %q", found.Ingredients[0].Name)
+	}
+	if len(found.Steps) != 1 {
+		t.Errorf("expected 1 step, got %d", len(found.Steps))
+	}
+}
+
+func TestRecipeRepository_GetByID_WithTranslation(t *testing.T) {
+	pool := testutil.SetupTestDB(t)
+	dishRepo := dish.NewRepository(pool)
+	recipeRepo := recipe.NewRepository(pool)
+	baseContext := context.Background()
+
+	recipeID, createError := dishRepo.Create(baseContext, dish.CreateRequest{
+		Name:        "Pasta Bolognese",
+		Description: "Classic Italian pasta",
+		Source:      "test",
+	})
+	if createError != nil {
+		t.Fatalf("create dish+recipe: %v", createError)
+	}
+
+	// Without translation context, the recipe should return English content.
+	enContext := locale.WithLang(baseContext, "en")
+	recipeEN, getError := recipeRepo.GetByID(enContext, recipeID)
+	if getError != nil {
+		t.Fatalf("get recipe (en): %v", getError)
+	}
+	if recipeEN == nil {
+		t.Fatal("expected recipe, got nil")
+	}
+
+	// With a language not having a translation, fallback to English should occur.
+	ruContext := locale.WithLang(baseContext, "ru")
+	recipeRU, getError := recipeRepo.GetByID(ruContext, recipeID)
+	if getError != nil {
+		t.Fatalf("get recipe (ru): %v", getError)
+	}
+	if recipeRU == nil {
+		t.Fatal("expected recipe with ru context, got nil")
+	}
+	// Both should refer to the same recipe ID.
+	if recipeEN.ID != recipeRU.ID {
+		t.Errorf("expected same recipe ID, got %q vs %q", recipeEN.ID, recipeRU.ID)
+	}
+}

backend/tests/recognition/merge_test.go

@@ -0,0 +1,90 @@
+package recognition_test
+
+import (
+	"testing"
+
+	"github.com/food-ai/backend/internal/adapters/ai"
+	"github.com/food-ai/backend/internal/domain/recognition"
+)
+
+func TestMergeAndDeduplicate_SingleBatch(t *testing.T) {
+	batches := [][]ai.RecognizedItem{
+		{
+			{Name: "apple", Quantity: 2, Unit: "pcs", Confidence: 0.9},
+			{Name: "banana", Quantity: 3, Unit: "pcs", Confidence: 0.8},
+		},
+	}
+
+	result := recognition.MergeAndDeduplicate(batches)
+
+	if len(result) != 2 {
+		t.Fatalf("expected 2 items, got %d", len(result))
+	}
+}
+
+func TestMergeAndDeduplicate_Duplicate(t *testing.T) {
+	batches := [][]ai.RecognizedItem{
+		{{Name: "apple", Quantity: 2, Unit: "pcs", Confidence: 0.7}},
+		{{Name: "apple", Quantity: 3, Unit: "pcs", Confidence: 0.8}},
+	}
+
+	result := recognition.MergeAndDeduplicate(batches)
+
+	if len(result) != 1 {
+		t.Fatalf("expected 1 item after dedup, got %d", len(result))
+	}
+	if result[0].Quantity != 5 {
+		t.Errorf("expected quantity 5 (2+3), got %v", result[0].Quantity)
+	}
+	if result[0].Confidence != 0.8 {
+		t.Errorf("expected confidence 0.8 (higher), got %v", result[0].Confidence)
+	}
+}
+
+func TestMergeAndDeduplicate_CaseInsensitive(t *testing.T) {
+	batches := [][]ai.RecognizedItem{
+		{{Name: "Apple", Quantity: 1, Unit: "pcs", Confidence: 0.9}},
+		{{Name: "apple", Quantity: 2, Unit: "pcs", Confidence: 0.7}},
+	}
+
+	result := recognition.MergeAndDeduplicate(batches)
+
+	if len(result) != 1 {
+		t.Fatalf("expected 1 item (case-insensitive dedup), got %d", len(result))
+	}
+	if result[0].Quantity != 3 {
+		t.Errorf("expected quantity 3, got %v", result[0].Quantity)
+	}
+}
+
+func TestMergeAndDeduplicate_KeepsHigherConfidence(t *testing.T) {
+	batches := [][]ai.RecognizedItem{
+		{{Name: "milk", Quantity: 1, Unit: "L", Confidence: 0.5}},
+		{{Name: "milk", Quantity: 1, Unit: "L", Confidence: 0.95}},
+	}
+
+	result := recognition.MergeAndDeduplicate(batches)
+
+	if len(result) != 1 {
+		t.Fatalf("expected 1 item, got %d", len(result))
+	}
+	if result[0].Confidence != 0.95 {
+		t.Errorf("expected confidence 0.95, got %v", result[0].Confidence)
+	}
+}
+
+func TestMergeAndDeduplicate_Empty(t *testing.T) {
+	result := recognition.MergeAndDeduplicate([][]ai.RecognizedItem{})
+
+	if len(result) != 0 {
+		t.Errorf("expected empty result, got %d items", len(result))
+	}
+}
+
+func TestMergeAndDeduplicate_NilBatches(t *testing.T) {
+	batches := [][]ai.RecognizedItem{nil, nil}
+	result := recognition.MergeAndDeduplicate(batches)
+	if len(result) != 0 {
+		t.Errorf("expected empty result for nil batches, got %d items", len(result))
+	}
+}

backend/tests/savedrecipe/handler_test.go

@@ -0,0 +1,186 @@
+package savedrecipe_test
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+	"time"
+
+	"github.com/food-ai/backend/internal/domain/savedrecipe"
+	savedrecipemocks "github.com/food-ai/backend/internal/domain/savedrecipe/mocks"
+	"github.com/food-ai/backend/internal/infra/middleware"
+	"github.com/go-chi/chi/v5"
+)
+
+type alwaysAuthValidator struct{ userID string }
+
+func (v *alwaysAuthValidator) ValidateAccessToken(_ string) (*middleware.TokenClaims, error) {
+	return &middleware.TokenClaims{UserID: v.userID}, nil
+}
+
+func buildRouter(handler *savedrecipe.Handler, userID string) *chi.Mux {
+	router := chi.NewRouter()
+	router.Use(middleware.Auth(&alwaysAuthValidator{userID: userID}))
+	router.Post("/saved-recipes", handler.Save)
+	router.Get("/saved-recipes", handler.List)
+	router.Get("/saved-recipes/{id}", handler.GetByID)
+	router.Delete("/saved-recipes/{id}", handler.Delete)
+	return router
+}
+
+func authorizedRequest(method, target string, body []byte) *http.Request {
+	request := httptest.NewRequest(method, target, bytes.NewReader(body))
+	request.Header.Set("Authorization", "Bearer test-token")
+	request.Header.Set("Content-Type", "application/json")
+	return request
+}
+
+func makeUserSavedRecipe(id string) *savedrecipe.UserSavedRecipe {
+	return &savedrecipe.UserSavedRecipe{
+		ID:          id,
+		UserID:      "user-1",
+		RecipeID:    "recipe-1",
+		SavedAt:     time.Now(),
+		DishName:    "Pasta Carbonara",
+		Ingredients: []savedrecipe.RecipeIngredient{},
+		Steps:       []savedrecipe.RecipeStep{},
+		Tags:        []string{},
+	}
+}
+
+func TestSave_MissingTitleAndRecipeID(t *testing.T) {
+	handler := savedrecipe.NewHandler(&savedrecipemocks.MockSavedRecipeRepository{})
+	router := buildRouter(handler, "user-1")
+
+	body, _ := json.Marshal(map[string]string{"cuisine": "italian"})
+	recorder := httptest.NewRecorder()
+	router.ServeHTTP(recorder, authorizedRequest(http.MethodPost, "/saved-recipes", body))
+
+	if recorder.Code != http.StatusBadRequest {
+		t.Errorf("expected 400, got %d", recorder.Code)
+	}
+}
+
+func TestSave_WithTitle(t *testing.T) {
+	mockRepo := &savedrecipemocks.MockSavedRecipeRepository{
+		SaveFn: func(ctx context.Context, userID string, req savedrecipe.SaveRequest) (*savedrecipe.UserSavedRecipe, error) {
+			return makeUserSavedRecipe("saved-1"), nil
+		},
+	}
+	handler := savedrecipe.NewHandler(mockRepo)
+	router := buildRouter(handler, "user-1")
+
+	body, _ := json.Marshal(savedrecipe.SaveRequest{Title: "My Recipe"})
+	recorder := httptest.NewRecorder()
+	router.ServeHTTP(recorder, authorizedRequest(http.MethodPost, "/saved-recipes", body))
+
+	if recorder.Code != http.StatusCreated {
+		t.Errorf("expected 201, got %d", recorder.Code)
+	}
+}
+
+func TestSave_WithRecipeID(t *testing.T) {
+	mockRepo := &savedrecipemocks.MockSavedRecipeRepository{
+		SaveFn: func(ctx context.Context, userID string, req savedrecipe.SaveRequest) (*savedrecipe.UserSavedRecipe, error) {
+			return makeUserSavedRecipe("saved-2"), nil
+		},
+	}
+	handler := savedrecipe.NewHandler(mockRepo)
+	router := buildRouter(handler, "user-1")
+
+	body, _ := json.Marshal(savedrecipe.SaveRequest{RecipeID: "recipe-42"})
+	recorder := httptest.NewRecorder()
+	router.ServeHTTP(recorder, authorizedRequest(http.MethodPost, "/saved-recipes", body))
+
+	if recorder.Code != http.StatusCreated {
+		t.Errorf("expected 201, got %d", recorder.Code)
+	}
+}
+
+func TestList_Success(t *testing.T) {
+	mockRepo := &savedrecipemocks.MockSavedRecipeRepository{
+		ListFn: func(ctx context.Context, userID string) ([]*savedrecipe.UserSavedRecipe, error) {
+			return []*savedrecipe.UserSavedRecipe{makeUserSavedRecipe("saved-1")}, nil
+		},
+	}
+	handler := savedrecipe.NewHandler(mockRepo)
+	router := buildRouter(handler, "user-1")
+
+	recorder := httptest.NewRecorder()
+	router.ServeHTTP(recorder, authorizedRequest(http.MethodGet, "/saved-recipes", nil))
+
+	if recorder.Code != http.StatusOK {
+		t.Errorf("expected 200, got %d", recorder.Code)
+	}
+}
+
+func TestGetByID_NotFound(t *testing.T) {
+	mockRepo := &savedrecipemocks.MockSavedRecipeRepository{
+		GetByIDFn: func(ctx context.Context, userID, id string) (*savedrecipe.UserSavedRecipe, error) {
+			return nil, nil
+		},
+	}
+	handler := savedrecipe.NewHandler(mockRepo)
+	router := buildRouter(handler, "user-1")
+
+	recorder := httptest.NewRecorder()
+	router.ServeHTTP(recorder, authorizedRequest(http.MethodGet, "/saved-recipes/nonexistent", nil))
+
+	if recorder.Code != http.StatusNotFound {
+		t.Errorf("expected 404, got %d", recorder.Code)
+	}
+}
+
+func TestGetByID_Success(t *testing.T) {
+	mockRepo := &savedrecipemocks.MockSavedRecipeRepository{
+		GetByIDFn: func(ctx context.Context, userID, id string) (*savedrecipe.UserSavedRecipe, error) {
+			return makeUserSavedRecipe(id), nil
+		},
+	}
+	handler := savedrecipe.NewHandler(mockRepo)
+	router := buildRouter(handler, "user-1")
+
+	recorder := httptest.NewRecorder()
+	router.ServeHTTP(recorder, authorizedRequest(http.MethodGet, "/saved-recipes/saved-1", nil))
+
+	if recorder.Code != http.StatusOK {
+		t.Errorf("expected 200, got %d", recorder.Code)
+	}
+}
+
+func TestDelete_NotFound(t *testing.T) {
+	mockRepo := &savedrecipemocks.MockSavedRecipeRepository{
+		DeleteFn: func(ctx context.Context, userID, id string) error {
+			return savedrecipe.ErrNotFound
+		},
+	}
+	handler := savedrecipe.NewHandler(mockRepo)
+	router := buildRouter(handler, "user-1")
+
+	recorder := httptest.NewRecorder()
+	router.ServeHTTP(recorder, authorizedRequest(http.MethodDelete, "/saved-recipes/nonexistent", nil))
+
+	if recorder.Code != http.StatusNotFound {
+		t.Errorf("expected 404, got %d", recorder.Code)
+	}
+}
+
+func TestDelete_Success(t *testing.T) {
+	mockRepo := &savedrecipemocks.MockSavedRecipeRepository{
+		DeleteFn: func(ctx context.Context, userID, id string) error {
+			return nil
+		},
+	}
+	handler := savedrecipe.NewHandler(mockRepo)
+	router := buildRouter(handler, "user-1")
+
+	recorder := httptest.NewRecorder()
+	router.ServeHTTP(recorder, authorizedRequest(http.MethodDelete, "/saved-recipes/saved-1", nil))
+
+	if recorder.Code != http.StatusNoContent {
+		t.Errorf("expected 204, got %d", recorder.Code)
+	}
+}

backend/tests/savedrecipe/map_cuisine_slug_test.go

@@ -0,0 +1,71 @@
+package savedrecipe_test
+
+import (
+	"testing"
+
+	"github.com/food-ai/backend/internal/domain/savedrecipe"
+)
+
+func TestMapCuisineSlug_KnownCuisines(t *testing.T) {
+	tests := []struct {
+		input string
+		want  string
+	}{
+		{"italian", "italian"},
+		{"french", "french"},
+		{"russian", "russian"},
+		{"chinese", "chinese"},
+		{"japanese", "japanese"},
+		{"korean", "korean"},
+		{"mexican", "mexican"},
+		{"mediterranean", "mediterranean"},
+		{"indian", "indian"},
+		{"thai", "thai"},
+		{"american", "american"},
+		{"georgian", "georgian"},
+		{"spanish", "spanish"},
+		{"german", "german"},
+		{"middle_eastern", "middle_eastern"},
+		{"turkish", "turkish"},
+		{"greek", "greek"},
+		{"vietnamese", "vietnamese"},
+	}
+
+	for _, tc := range tests {
+		result := savedrecipe.MapCuisineSlug(tc.input)
+		if result != tc.want {
+			t.Errorf("MapCuisineSlug(%q) = %q, want %q", tc.input, result, tc.want)
+		}
+	}
+}
+
+func TestMapCuisineSlug_GenericFallsToOther(t *testing.T) {
+	for _, input := range []string{"asian", "european"} {
+		result := savedrecipe.MapCuisineSlug(input)
+		if result != "other" {
+			t.Errorf("MapCuisineSlug(%q) = %q, want %q", input, result, "other")
+		}
+	}
+}
+
+func TestMapCuisineSlug_Unknown(t *testing.T) {
+	result := savedrecipe.MapCuisineSlug("peruvian")
+	if result != "other" {
+		t.Errorf("MapCuisineSlug(peruvian) = %q, want %q", result, "other")
+	}
+}
+
+func TestMapCuisineSlug_Empty(t *testing.T) {
+	result := savedrecipe.MapCuisineSlug("")
+	if result != "other" {
+		t.Errorf("MapCuisineSlug() = %q, want %q", result, "other")
+	}
+}
+
+func TestMapCuisineSlug_CaseSensitive(t *testing.T) {
+	// The function does NOT lowercase — "ITALIAN" is unknown and falls back to "other".
+	result := savedrecipe.MapCuisineSlug("ITALIAN")
+	if result != "other" {
+		t.Errorf("MapCuisineSlug(ITALIAN) = %q, want %q", result, "other")
+	}
+}