refactor: move all tests to backend/tests/ as black-box packages

All test files relocated from internal/X/ to tests/X/ and converted
to package X_test, using only the public API of each package.

- tests/auth/: jwt, service, handler integration tests
- tests/middleware/: auth, request_id, recovery tests
- tests/user/: calories, service, repository integration tests
- tests/locale/: locale tests (already package locale_test, just moved)
- tests/ingredient/: repository integration tests
- tests/recipe/: repository integration tests

mockUserRepo in tests/user/service_test.go redefined locally with
fully-qualified user.* types. Unexported auth.refreshRequest replaced
with a local testRefreshRequest struct in the integration test.

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

backend/tests/auth/handler_integration_test.go

@@ -0,0 +1,278 @@
+//go:build integration
+
+package auth_test
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+	"time"
+
+	"github.com/food-ai/backend/internal/auth"
+	"github.com/food-ai/backend/internal/auth/mocks"
+	"github.com/food-ai/backend/internal/middleware"
+	"github.com/food-ai/backend/internal/testutil"
+	"github.com/food-ai/backend/internal/user"
+	"github.com/go-chi/chi/v5"
+)
+
+// testRefreshRequest mirrors the unexported handler request type for test marshalling.
+type testRefreshRequest struct {
+	RefreshToken string `json:"refresh_token"`
+}
+
+// testValidator adapts auth.JWTManager to middleware.AccessTokenValidator for tests.
+type testValidator struct {
+	jm *auth.JWTManager
+}
+
+func (v *testValidator) ValidateAccessToken(tokenStr string) (*middleware.TokenClaims, error) {
+	claims, validateError := v.jm.ValidateAccessToken(tokenStr)
+	if validateError != nil {
+		return nil, validateError
+	}
+	return &middleware.TokenClaims{UserID: claims.UserID, Plan: claims.Plan}, nil
+}
+
+func setupIntegrationTest(t *testing.T) (*chi.Mux, *auth.JWTManager) {
+	t.Helper()
+	pool := testutil.SetupTestDB(t)
+
+	verifier := &mocks.MockTokenVerifier{
+		VerifyTokenFn: func(ctx context.Context, idToken string) (string, string, string, string, error) {
+			return "fb-" + idToken, idToken + "@test.com", "Test User", "", nil
+		},
+	}
+
+	jm := auth.NewJWTManager("test-secret", 15*time.Minute, 720*time.Hour)
+	repo := user.NewRepository(pool)
+	svc := auth.NewService(verifier, repo, jm)
+	handler := auth.NewHandler(svc)
+
+	r := chi.NewRouter()
+	r.Post("/auth/login", handler.Login)
+	r.Post("/auth/refresh", handler.Refresh)
+	r.Group(func(r chi.Router) {
+		r.Use(middleware.Auth(&testValidator{jm: jm}))
+		r.Post("/auth/logout", handler.Logout)
+	})
+
+	return r, jm
+}
+
+func TestIntegration_Login(t *testing.T) {
+	router, _ := setupIntegrationTest(t)
+
+	body := `{"firebase_token":"user1"}`
+	req := httptest.NewRequest("POST", "/auth/login", bytes.NewBufferString(body))
+	req.Header.Set("Content-Type", "application/json")
+	rr := httptest.NewRecorder()
+
+	router.ServeHTTP(rr, req)
+	if rr.Code != http.StatusOK {
+		t.Fatalf("expected 200, got %d: %s", rr.Code, rr.Body.String())
+	}
+
+	var resp auth.LoginResponse
+	json.NewDecoder(rr.Body).Decode(&resp)
+	if resp.AccessToken == "" {
+		t.Error("expected non-empty access token")
+	}
+	if resp.RefreshToken == "" {
+		t.Error("expected non-empty refresh token")
+	}
+	if resp.User == nil {
+		t.Fatal("expected user in response")
+	}
+}
+
+func TestIntegration_Login_EmptyToken(t *testing.T) {
+	router, _ := setupIntegrationTest(t)
+
+	body := `{"firebase_token":""}`
+	req := httptest.NewRequest("POST", "/auth/login", bytes.NewBufferString(body))
+	req.Header.Set("Content-Type", "application/json")
+	rr := httptest.NewRecorder()
+
+	router.ServeHTTP(rr, req)
+	if rr.Code != http.StatusBadRequest {
+		t.Errorf("expected 400, got %d", rr.Code)
+	}
+}
+
+func TestIntegration_Login_InvalidBody(t *testing.T) {
+	router, _ := setupIntegrationTest(t)
+
+	req := httptest.NewRequest("POST", "/auth/login", bytes.NewBufferString("invalid"))
+	req.Header.Set("Content-Type", "application/json")
+	rr := httptest.NewRecorder()
+
+	router.ServeHTTP(rr, req)
+	if rr.Code != http.StatusBadRequest {
+		t.Errorf("expected 400, got %d", rr.Code)
+	}
+}
+
+func TestIntegration_Refresh(t *testing.T) {
+	router, _ := setupIntegrationTest(t)
+
+	// First login
+	loginBody := `{"firebase_token":"user2"}`
+	loginReq := httptest.NewRequest("POST", "/auth/login", bytes.NewBufferString(loginBody))
+	loginReq.Header.Set("Content-Type", "application/json")
+	loginRR := httptest.NewRecorder()
+	router.ServeHTTP(loginRR, loginReq)
+
+	var loginResp auth.LoginResponse
+	json.NewDecoder(loginRR.Body).Decode(&loginResp)
+
+	// Then refresh
+	refreshBody, _ := json.Marshal(testRefreshRequest{RefreshToken: loginResp.RefreshToken})
+	refreshReq := httptest.NewRequest("POST", "/auth/refresh", bytes.NewBuffer(refreshBody))
+	refreshReq.Header.Set("Content-Type", "application/json")
+	refreshRR := httptest.NewRecorder()
+	router.ServeHTTP(refreshRR, refreshReq)
+
+	if refreshRR.Code != http.StatusOK {
+		t.Fatalf("expected 200, got %d: %s", refreshRR.Code, refreshRR.Body.String())
+	}
+
+	var resp auth.RefreshResponse
+	json.NewDecoder(refreshRR.Body).Decode(&resp)
+	if resp.AccessToken == "" {
+		t.Error("expected non-empty access token")
+	}
+	if resp.RefreshToken == loginResp.RefreshToken {
+		t.Error("expected rotated refresh token")
+	}
+}
+
+func TestIntegration_Refresh_InvalidToken(t *testing.T) {
+	router, _ := setupIntegrationTest(t)
+
+	body := `{"refresh_token":"nonexistent"}`
+	req := httptest.NewRequest("POST", "/auth/refresh", bytes.NewBufferString(body))
+	req.Header.Set("Content-Type", "application/json")
+	rr := httptest.NewRecorder()
+
+	router.ServeHTTP(rr, req)
+	if rr.Code != http.StatusUnauthorized {
+		t.Errorf("expected 401, got %d", rr.Code)
+	}
+}
+
+func TestIntegration_Refresh_EmptyToken(t *testing.T) {
+	router, _ := setupIntegrationTest(t)
+
+	body := `{"refresh_token":""}`
+	req := httptest.NewRequest("POST", "/auth/refresh", bytes.NewBufferString(body))
+	req.Header.Set("Content-Type", "application/json")
+	rr := httptest.NewRecorder()
+
+	router.ServeHTTP(rr, req)
+	if rr.Code != http.StatusBadRequest {
+		t.Errorf("expected 400, got %d", rr.Code)
+	}
+}
+
+func TestIntegration_Logout(t *testing.T) {
+	router, _ := setupIntegrationTest(t)
+
+	// Login first
+	loginBody := `{"firebase_token":"user3"}`
+	loginReq := httptest.NewRequest("POST", "/auth/login", bytes.NewBufferString(loginBody))
+	loginReq.Header.Set("Content-Type", "application/json")
+	loginRR := httptest.NewRecorder()
+	router.ServeHTTP(loginRR, loginReq)
+
+	var loginResp auth.LoginResponse
+	json.NewDecoder(loginRR.Body).Decode(&loginResp)
+
+	// Logout
+	logoutReq := httptest.NewRequest("POST", "/auth/logout", nil)
+	logoutReq.Header.Set("Authorization", "Bearer "+loginResp.AccessToken)
+	logoutRR := httptest.NewRecorder()
+	router.ServeHTTP(logoutRR, logoutReq)
+
+	if logoutRR.Code != http.StatusOK {
+		t.Errorf("expected 200, got %d: %s", logoutRR.Code, logoutRR.Body.String())
+	}
+}
+
+func TestIntegration_Logout_NoAuth(t *testing.T) {
+	router, _ := setupIntegrationTest(t)
+
+	req := httptest.NewRequest("POST", "/auth/logout", nil)
+	rr := httptest.NewRecorder()
+
+	router.ServeHTTP(rr, req)
+	if rr.Code != http.StatusUnauthorized {
+		t.Errorf("expected 401, got %d", rr.Code)
+	}
+}
+
+func TestIntegration_RefreshAfterLogout(t *testing.T) {
+	router, _ := setupIntegrationTest(t)
+
+	// Login
+	loginBody := `{"firebase_token":"user4"}`
+	loginReq := httptest.NewRequest("POST", "/auth/login", bytes.NewBufferString(loginBody))
+	loginReq.Header.Set("Content-Type", "application/json")
+	loginRR := httptest.NewRecorder()
+	router.ServeHTTP(loginRR, loginReq)
+
+	var loginResp auth.LoginResponse
+	json.NewDecoder(loginRR.Body).Decode(&loginResp)
+
+	// Logout
+	logoutReq := httptest.NewRequest("POST", "/auth/logout", nil)
+	logoutReq.Header.Set("Authorization", "Bearer "+loginResp.AccessToken)
+	logoutRR := httptest.NewRecorder()
+	router.ServeHTTP(logoutRR, logoutReq)
+
+	// Try to refresh with old token
+	refreshBody, _ := json.Marshal(testRefreshRequest{RefreshToken: loginResp.RefreshToken})
+	refreshReq := httptest.NewRequest("POST", "/auth/refresh", bytes.NewBuffer(refreshBody))
+	refreshReq.Header.Set("Content-Type", "application/json")
+	refreshRR := httptest.NewRecorder()
+	router.ServeHTTP(refreshRR, refreshReq)
+
+	if refreshRR.Code != http.StatusUnauthorized {
+		t.Errorf("expected 401 after logout, got %d", refreshRR.Code)
+	}
+}
+
+func TestIntegration_OldRefreshTokenInvalid(t *testing.T) {
+	router, _ := setupIntegrationTest(t)
+
+	// Login
+	loginBody := `{"firebase_token":"user5"}`
+	loginReq := httptest.NewRequest("POST", "/auth/login", bytes.NewBufferString(loginBody))
+	loginReq.Header.Set("Content-Type", "application/json")
+	loginRR := httptest.NewRecorder()
+	router.ServeHTTP(loginRR, loginReq)
+
+	var loginResp auth.LoginResponse
+	json.NewDecoder(loginRR.Body).Decode(&loginResp)
+	oldRefreshToken := loginResp.RefreshToken
+
+	// Refresh (rotates token)
+	refreshBody, _ := json.Marshal(testRefreshRequest{RefreshToken: oldRefreshToken})
+	refreshReq := httptest.NewRequest("POST", "/auth/refresh", bytes.NewBuffer(refreshBody))
+	refreshReq.Header.Set("Content-Type", "application/json")
+	refreshRR := httptest.NewRecorder()
+	router.ServeHTTP(refreshRR, refreshReq)
+
+	// Try old refresh token again
+	oldRefreshReq := httptest.NewRequest("POST", "/auth/refresh", bytes.NewBuffer(refreshBody))
+	oldRefreshReq.Header.Set("Content-Type", "application/json")
+	oldRefreshRR := httptest.NewRecorder()
+	router.ServeHTTP(oldRefreshRR, oldRefreshReq)
+
+	if oldRefreshRR.Code != http.StatusUnauthorized {
+		t.Errorf("expected 401 for old refresh token, got %d", oldRefreshRR.Code)
+	}
+}

backend/tests/auth/jwt_test.go

@@ -0,0 +1,88 @@
+package auth_test
+
+import (
+	"testing"
+	"time"
+
+	"github.com/food-ai/backend/internal/auth"
+)
+
+func TestGenerateAccessToken(t *testing.T) {
+	jm := auth.NewJWTManager("test-secret", 15*time.Minute, 720*time.Hour)
+
+	token, tokenError := jm.GenerateAccessToken("user-123", "free")
+	if tokenError != nil {
+		t.Fatalf("unexpected error: %v", tokenError)
+	}
+	if token == "" {
+		t.Fatal("expected non-empty token")
+	}
+}
+
+func TestValidateAccessToken_Valid(t *testing.T) {
+	jm := auth.NewJWTManager("test-secret", 15*time.Minute, 720*time.Hour)
+
+	token, _ := jm.GenerateAccessToken("user-123", "free")
+	claims, validateError := jm.ValidateAccessToken(token)
+	if validateError != nil {
+		t.Fatalf("unexpected error: %v", validateError)
+	}
+	if claims.UserID != "user-123" {
+		t.Errorf("expected user_id 'user-123', got %q", claims.UserID)
+	}
+	if claims.Plan != "free" {
+		t.Errorf("expected plan 'free', got %q", claims.Plan)
+	}
+}
+
+func TestValidateAccessToken_Expired(t *testing.T) {
+	jm := auth.NewJWTManager("test-secret", -1*time.Second, 720*time.Hour)
+
+	token, _ := jm.GenerateAccessToken("user-123", "free")
+	_, validateError := jm.ValidateAccessToken(token)
+	if validateError == nil {
+		t.Fatal("expected error for expired token")
+	}
+}
+
+func TestValidateAccessToken_WrongSecret(t *testing.T) {
+	jm1 := auth.NewJWTManager("secret-1", 15*time.Minute, 720*time.Hour)
+	jm2 := auth.NewJWTManager("secret-2", 15*time.Minute, 720*time.Hour)
+
+	token, _ := jm1.GenerateAccessToken("user-123", "free")
+	_, validateError := jm2.ValidateAccessToken(token)
+	if validateError == nil {
+		t.Fatal("expected error for wrong secret")
+	}
+}
+
+func TestValidateAccessToken_InvalidToken(t *testing.T) {
+	jm := auth.NewJWTManager("test-secret", 15*time.Minute, 720*time.Hour)
+
+	_, validateError := jm.ValidateAccessToken("invalid-token")
+	if validateError == nil {
+		t.Fatal("expected error for invalid token")
+	}
+}
+
+func TestGenerateRefreshToken(t *testing.T) {
+	jm := auth.NewJWTManager("test-secret", 15*time.Minute, 720*time.Hour)
+
+	token, expiresAt := jm.GenerateRefreshToken()
+	if token == "" {
+		t.Fatal("expected non-empty refresh token")
+	}
+	if expiresAt.Before(time.Now()) {
+		t.Fatal("expected future expiration time")
+	}
+}
+
+func TestGenerateRefreshToken_Unique(t *testing.T) {
+	jm := auth.NewJWTManager("test-secret", 15*time.Minute, 720*time.Hour)
+
+	token1, _ := jm.GenerateRefreshToken()
+	token2, _ := jm.GenerateRefreshToken()
+	if token1 == token2 {
+		t.Fatal("expected unique refresh tokens")
+	}
+}

backend/tests/auth/service_test.go

@@ -0,0 +1,214 @@
+package auth_test
+
+import (
+	"context"
+	"fmt"
+	"testing"
+	"time"
+
+	"github.com/food-ai/backend/internal/auth"
+	"github.com/food-ai/backend/internal/auth/mocks"
+	"github.com/food-ai/backend/internal/user"
+	umocks "github.com/food-ai/backend/internal/user/mocks"
+)
+
+func newTestService(verifier *mocks.MockTokenVerifier, repo *umocks.MockUserRepository) *auth.Service {
+	jm := auth.NewJWTManager("test-secret", 15*time.Minute, 720*time.Hour)
+	return auth.NewService(verifier, repo, jm)
+}
+
+func TestLogin_Success(t *testing.T) {
+	verifier := &mocks.MockTokenVerifier{
+		VerifyTokenFn: func(ctx context.Context, idToken string) (string, string, string, string, error) {
+			return "fb-uid", "test@example.com", "Test User", "https://avatar.url", nil
+		},
+	}
+	repo := &umocks.MockUserRepository{
+		UpsertByFirebaseUIDFn: func(ctx context.Context, uid, email, name, avatarURL string) (*user.User, error) {
+			return &user.User{ID: "user-1", Email: email, Name: name, Plan: "free"}, nil
+		},
+		SetRefreshTokenFn: func(ctx context.Context, id, token string, expiresAt time.Time) error {
+			return nil
+		},
+	}
+
+	svc := newTestService(verifier, repo)
+	resp, loginError := svc.Login(context.Background(), "firebase-token")
+	if loginError != nil {
+		t.Fatalf("unexpected error: %v", loginError)
+	}
+	if resp.AccessToken == "" {
+		t.Error("expected non-empty access token")
+	}
+	if resp.RefreshToken == "" {
+		t.Error("expected non-empty refresh token")
+	}
+	if resp.User.ID != "user-1" {
+		t.Errorf("expected user ID 'user-1', got %q", resp.User.ID)
+	}
+}
+
+func TestLogin_InvalidFirebaseToken(t *testing.T) {
+	verifier := &mocks.MockTokenVerifier{
+		VerifyTokenFn: func(ctx context.Context, idToken string) (string, string, string, string, error) {
+			return "", "", "", "", fmt.Errorf("invalid token")
+		},
+	}
+	repo := &umocks.MockUserRepository{}
+
+	svc := newTestService(verifier, repo)
+	_, loginError := svc.Login(context.Background(), "bad-token")
+	if loginError == nil {
+		t.Fatal("expected error for invalid firebase token")
+	}
+}
+
+func TestLogin_UpsertError(t *testing.T) {
+	verifier := &mocks.MockTokenVerifier{
+		VerifyTokenFn: func(ctx context.Context, idToken string) (string, string, string, string, error) {
+			return "fb-uid", "test@example.com", "Test", "", nil
+		},
+	}
+	repo := &umocks.MockUserRepository{
+		UpsertByFirebaseUIDFn: func(ctx context.Context, uid, email, name, avatarURL string) (*user.User, error) {
+			return nil, fmt.Errorf("db error")
+		},
+	}
+
+	svc := newTestService(verifier, repo)
+	_, loginError := svc.Login(context.Background(), "token")
+	if loginError == nil {
+		t.Fatal("expected error for upsert failure")
+	}
+}
+
+func TestLogin_SetRefreshTokenError(t *testing.T) {
+	verifier := &mocks.MockTokenVerifier{
+		VerifyTokenFn: func(ctx context.Context, idToken string) (string, string, string, string, error) {
+			return "fb-uid", "test@example.com", "Test", "", nil
+		},
+	}
+	repo := &umocks.MockUserRepository{
+		UpsertByFirebaseUIDFn: func(ctx context.Context, uid, email, name, avatarURL string) (*user.User, error) {
+			return &user.User{ID: "user-1", Plan: "free"}, nil
+		},
+		SetRefreshTokenFn: func(ctx context.Context, id, token string, expiresAt time.Time) error {
+			return fmt.Errorf("db error")
+		},
+	}
+
+	svc := newTestService(verifier, repo)
+	_, loginError := svc.Login(context.Background(), "token")
+	if loginError == nil {
+		t.Fatal("expected error for set refresh token failure")
+	}
+}
+
+func TestRefresh_Success(t *testing.T) {
+	repo := &umocks.MockUserRepository{
+		FindByRefreshTokenFn: func(ctx context.Context, token string) (*user.User, error) {
+			return &user.User{ID: "user-1", Plan: "free"}, nil
+		},
+		SetRefreshTokenFn: func(ctx context.Context, id, token string, expiresAt time.Time) error {
+			return nil
+		},
+	}
+	verifier := &mocks.MockTokenVerifier{}
+
+	svc := newTestService(verifier, repo)
+	resp, refreshError := svc.Refresh(context.Background(), "valid-refresh-token")
+	if refreshError != nil {
+		t.Fatalf("unexpected error: %v", refreshError)
+	}
+	if resp.AccessToken == "" {
+		t.Error("expected non-empty access token")
+	}
+	if resp.RefreshToken == "" {
+		t.Error("expected non-empty refresh token")
+	}
+}
+
+func TestRefresh_InvalidToken(t *testing.T) {
+	repo := &umocks.MockUserRepository{
+		FindByRefreshTokenFn: func(ctx context.Context, token string) (*user.User, error) {
+			return nil, fmt.Errorf("not found")
+		},
+	}
+	verifier := &mocks.MockTokenVerifier{}
+
+	svc := newTestService(verifier, repo)
+	_, refreshError := svc.Refresh(context.Background(), "bad-token")
+	if refreshError == nil {
+		t.Fatal("expected error for invalid refresh token")
+	}
+}
+
+func TestRefresh_SetRefreshTokenError(t *testing.T) {
+	repo := &umocks.MockUserRepository{
+		FindByRefreshTokenFn: func(ctx context.Context, token string) (*user.User, error) {
+			return &user.User{ID: "user-1", Plan: "free"}, nil
+		},
+		SetRefreshTokenFn: func(ctx context.Context, id, token string, expiresAt time.Time) error {
+			return fmt.Errorf("db error")
+		},
+	}
+	verifier := &mocks.MockTokenVerifier{}
+
+	svc := newTestService(verifier, repo)
+	_, refreshError := svc.Refresh(context.Background(), "valid-token")
+	if refreshError == nil {
+		t.Fatal("expected error")
+	}
+}
+
+func TestLogout_Success(t *testing.T) {
+	repo := &umocks.MockUserRepository{
+		ClearRefreshTokenFn: func(ctx context.Context, id string) error {
+			return nil
+		},
+	}
+	verifier := &mocks.MockTokenVerifier{}
+
+	svc := newTestService(verifier, repo)
+	logoutError := svc.Logout(context.Background(), "user-1")
+	if logoutError != nil {
+		t.Fatalf("unexpected error: %v", logoutError)
+	}
+}
+
+func TestLogout_Error(t *testing.T) {
+	repo := &umocks.MockUserRepository{
+		ClearRefreshTokenFn: func(ctx context.Context, id string) error {
+			return fmt.Errorf("db error")
+		},
+	}
+	verifier := &mocks.MockTokenVerifier{}
+
+	svc := newTestService(verifier, repo)
+	logoutError := svc.Logout(context.Background(), "user-1")
+	if logoutError == nil {
+		t.Fatal("expected error")
+	}
+}
+
+func TestLogin_ExpiresIn(t *testing.T) {
+	verifier := &mocks.MockTokenVerifier{
+		VerifyTokenFn: func(ctx context.Context, idToken string) (string, string, string, string, error) {
+			return "fb-uid", "test@example.com", "Test", "", nil
+		},
+	}
+	repo := &umocks.MockUserRepository{
+		UpsertByFirebaseUIDFn: func(ctx context.Context, uid, email, name, avatarURL string) (*user.User, error) {
+			return &user.User{ID: "user-1", Plan: "free"}, nil
+		},
+		SetRefreshTokenFn: func(ctx context.Context, id, token string, expiresAt time.Time) error {
+			return nil
+		},
+	}
+
+	svc := newTestService(verifier, repo)
+	resp, _ := svc.Login(context.Background(), "token")
+	if resp.ExpiresIn != 900 {
+		t.Errorf("expected expires_in 900, got %d", resp.ExpiresIn)
+	}
+}

backend/tests/ingredient/repository_integration_test.go

@@ -0,0 +1,297 @@
+//go:build integration
+
+package ingredient_test
+
+import (
+	"context"
+	"testing"
+
+	"github.com/food-ai/backend/internal/ingredient"
+	"github.com/food-ai/backend/internal/locale"
+	"github.com/food-ai/backend/internal/testutil"
+)
+
+func TestIngredientRepository_Upsert_Insert(t *testing.T) {
+	pool := testutil.SetupTestDB(t)
+	repo := ingredient.NewRepository(pool)
+	ctx := context.Background()
+
+	cat := "produce"
+	unit := "g"
+	cal := 52.0
+
+	mapping := &ingredient.IngredientMapping{
+		CanonicalName:   "apple",
+		Category:        &cat,
+		DefaultUnit:     &unit,
+		CaloriesPer100g: &cal,
+	}
+
+	got, upsertError := repo.Upsert(ctx, mapping)
+	if upsertError != nil {
+		t.Fatalf("upsert: %v", upsertError)
+	}
+	if got.ID == "" {
+		t.Error("expected non-empty ID")
+	}
+	if got.CanonicalName != "apple" {
+		t.Errorf("canonical_name: want apple, got %s", got.CanonicalName)
+	}
+	if *got.CaloriesPer100g != 52.0 {
+		t.Errorf("calories: want 52.0, got %v", got.CaloriesPer100g)
+	}
+}
+
+func TestIngredientRepository_Upsert_ConflictUpdates(t *testing.T) {
+	pool := testutil.SetupTestDB(t)
+	repo := ingredient.NewRepository(pool)
+	ctx := context.Background()
+
+	cat := "produce"
+	unit := "g"
+
+	first := &ingredient.IngredientMapping{
+		CanonicalName: "banana",
+		Category:      &cat,
+		DefaultUnit:   &unit,
+	}
+	got1, firstUpsertError := repo.Upsert(ctx, first)
+	if firstUpsertError != nil {
+		t.Fatalf("first upsert: %v", firstUpsertError)
+	}
+
+	cal := 89.0
+	second := &ingredient.IngredientMapping{
+		CanonicalName:   "banana",
+		Category:        &cat,
+		DefaultUnit:     &unit,
+		CaloriesPer100g: &cal,
+	}
+	got2, secondUpsertError := repo.Upsert(ctx, second)
+	if secondUpsertError != nil {
+		t.Fatalf("second upsert: %v", secondUpsertError)
+	}
+
+	if got1.ID != got2.ID {
+		t.Errorf("ID changed on conflict update: %s != %s", got1.ID, got2.ID)
+	}
+	if got2.CanonicalName != "banana" {
+		t.Errorf("canonical_name not updated: got %s", got2.CanonicalName)
+	}
+	if got2.CaloriesPer100g == nil || *got2.CaloriesPer100g != 89.0 {
+		t.Errorf("calories not updated: got %v", got2.CaloriesPer100g)
+	}
+}
+
+func TestIngredientRepository_GetByID_Found(t *testing.T) {
+	pool := testutil.SetupTestDB(t)
+	repo := ingredient.NewRepository(pool)
+	ctx := context.Background()
+
+	cat := "dairy"
+	unit := "g"
+
+	saved, upsertError := repo.Upsert(ctx, &ingredient.IngredientMapping{
+		CanonicalName: "cheese",
+		Category:      &cat,
+		DefaultUnit:   &unit,
+	})
+	if upsertError != nil {
+		t.Fatalf("upsert: %v", upsertError)
+	}
+
+	got, getError := repo.GetByID(ctx, saved.ID)
+	if getError != nil {
+		t.Fatalf("get: %v", getError)
+	}
+	if got == nil {
+		t.Fatal("expected non-nil result")
+	}
+	if got.CanonicalName != "cheese" {
+		t.Errorf("want cheese, got %s", got.CanonicalName)
+	}
+}
+
+func TestIngredientRepository_GetByID_NotFound(t *testing.T) {
+	pool := testutil.SetupTestDB(t)
+	repo := ingredient.NewRepository(pool)
+	ctx := context.Background()
+
+	got, getError := repo.GetByID(ctx, "00000000-0000-0000-0000-000000000000")
+	if getError != nil {
+		t.Fatalf("unexpected error: %v", getError)
+	}
+	if got != nil {
+		t.Error("expected nil result for missing ID")
+	}
+}
+
+func TestIngredientRepository_ListMissingTranslation(t *testing.T) {
+	pool := testutil.SetupTestDB(t)
+	repo := ingredient.NewRepository(pool)
+	ctx := context.Background()
+
+	cat := "produce"
+	unit := "g"
+
+	// Insert 3 without any translation.
+	for _, name := range []string{"carrot", "onion", "garlic"} {
+		_, upsertError := repo.Upsert(ctx, &ingredient.IngredientMapping{
+			CanonicalName: name,
+			Category:      &cat,
+			DefaultUnit:   &unit,
+		})
+		if upsertError != nil {
+			t.Fatalf("upsert %s: %v", name, upsertError)
+		}
+	}
+
+	// Insert 1 and add a translation — should not appear in the result.
+	saved, upsertError := repo.Upsert(ctx, &ingredient.IngredientMapping{
+		CanonicalName: "tomato",
+		Category:      &cat,
+		DefaultUnit:   &unit,
+	})
+	if upsertError != nil {
+		t.Fatalf("upsert tomato: %v", upsertError)
+	}
+	if translationError := repo.UpsertTranslation(ctx, saved.ID, "ru", "помидор"); translationError != nil {
+		t.Fatalf("upsert translation: %v", translationError)
+	}
+
+	missing, listError := repo.ListMissingTranslation(ctx, "ru", 10, 0)
+	if listError != nil {
+		t.Fatalf("list missing translation: %v", listError)
+	}
+
+	for _, mapping := range missing {
+		if mapping.CanonicalName == "tomato" {
+			t.Error("translated ingredient should not appear in ListMissingTranslation")
+		}
+	}
+	if len(missing) < 3 {
+		t.Errorf("expected at least 3 untranslated, got %d", len(missing))
+	}
+}
+
+func TestIngredientRepository_UpsertTranslation(t *testing.T) {
+	pool := testutil.SetupTestDB(t)
+	repo := ingredient.NewRepository(pool)
+	ctx := context.Background()
+
+	cat := "meat"
+	unit := "g"
+
+	saved, upsertError := repo.Upsert(ctx, &ingredient.IngredientMapping{
+		CanonicalName: "chicken_breast",
+		Category:      &cat,
+		DefaultUnit:   &unit,
+	})
+	if upsertError != nil {
+		t.Fatalf("upsert: %v", upsertError)
+	}
+
+	if translationError := repo.UpsertTranslation(ctx, saved.ID, "ru", "куриная грудка"); translationError != nil {
+		t.Fatalf("upsert translation: %v", translationError)
+	}
+
+	// Retrieve with Russian context — CanonicalName should be the Russian name.
+	russianContext := locale.WithLang(ctx, "ru")
+	got, getError := repo.GetByID(russianContext, saved.ID)
+	if getError != nil {
+		t.Fatalf("get by id: %v", getError)
+	}
+	if got.CanonicalName != "куриная грудка" {
+		t.Errorf("expected CanonicalName='куриная грудка', got %q", got.CanonicalName)
+	}
+
+	// Retrieve with English context (default) — CanonicalName should be the English name.
+	englishContext := locale.WithLang(ctx, "en")
+	gotEnglish, getEnglishError := repo.GetByID(englishContext, saved.ID)
+	if getEnglishError != nil {
+		t.Fatalf("get by id (en): %v", getEnglishError)
+	}
+	if gotEnglish.CanonicalName != "chicken_breast" {
+		t.Errorf("expected English CanonicalName='chicken_breast', got %q", gotEnglish.CanonicalName)
+	}
+}
+
+func TestIngredientRepository_UpsertAliases(t *testing.T) {
+	pool := testutil.SetupTestDB(t)
+	repo := ingredient.NewRepository(pool)
+	ctx := context.Background()
+
+	cat := "produce"
+	unit := "g"
+
+	saved, upsertError := repo.Upsert(ctx, &ingredient.IngredientMapping{
+		CanonicalName: "apple_test_aliases",
+		Category:      &cat,
+		DefaultUnit:   &unit,
+	})
+	if upsertError != nil {
+		t.Fatalf("upsert: %v", upsertError)
+	}
+
+	aliases := []string{"apple", "apples", "red apple"}
+	if aliasError := repo.UpsertAliases(ctx, saved.ID, "en", aliases); aliasError != nil {
+		t.Fatalf("upsert aliases: %v", aliasError)
+	}
+
+	// Idempotent — second call should not fail.
+	if aliasError := repo.UpsertAliases(ctx, saved.ID, "en", aliases); aliasError != nil {
+		t.Fatalf("second upsert aliases: %v", aliasError)
+	}
+
+	// Retrieve with English context — aliases should appear.
+	englishContext := locale.WithLang(ctx, "en")
+	got, getError := repo.GetByID(englishContext, saved.ID)
+	if getError != nil {
+		t.Fatalf("get by id: %v", getError)
+	}
+	if string(got.Aliases) == "[]" || string(got.Aliases) == "null" {
+		t.Errorf("expected non-empty aliases, got %s", got.Aliases)
+	}
+}
+
+func TestIngredientRepository_UpsertCategoryTranslation(t *testing.T) {
+	pool := testutil.SetupTestDB(t)
+	repo := ingredient.NewRepository(pool)
+	ctx := context.Background()
+
+	// Upsert an ingredient with a known category.
+	cat := "dairy"
+	unit := "g"
+	saved, upsertError := repo.Upsert(ctx, &ingredient.IngredientMapping{
+		CanonicalName: "milk_test_category",
+		Category:      &cat,
+		DefaultUnit:   &unit,
+	})
+	if upsertError != nil {
+		t.Fatalf("upsert: %v", upsertError)
+	}
+
+	// The migration already inserted Russian translations for known categories.
+	// Retrieve with Russian context — CategoryName should be set.
+	russianContext := locale.WithLang(ctx, "ru")
+	got, getError := repo.GetByID(russianContext, saved.ID)
+	if getError != nil {
+		t.Fatalf("get by id: %v", getError)
+	}
+	if got.CategoryName == nil || *got.CategoryName == "" {
+		t.Error("expected non-empty CategoryName for 'dairy' in Russian")
+	}
+
+	// Upsert a new translation and verify it is returned.
+	if translationError := repo.UpsertCategoryTranslation(ctx, "dairy", "de", "Milchprodukte"); translationError != nil {
+		t.Fatalf("upsert category translation: %v", translationError)
+	}
+	germanContext := locale.WithLang(ctx, "de")
+	gotGerman, getGermanError := repo.GetByID(germanContext, saved.ID)
+	if getGermanError != nil {
+		t.Fatalf("get by id (de): %v", getGermanError)
+	}
+	if gotGerman.CategoryName == nil || *gotGerman.CategoryName != "Milchprodukte" {
+		t.Errorf("expected CategoryName='Milchprodukte', got %v", gotGerman.CategoryName)
+	}
+}

backend/tests/locale/locale_test.go

@@ -0,0 +1,94 @@
+package locale_test
+
+import (
+	"context"
+	"net/http"
+	"testing"
+
+	"github.com/food-ai/backend/internal/locale"
+)
+
+func TestParse(t *testing.T) {
+	tests := []struct {
+		name       string
+		acceptLang string
+		want       string
+	}{
+		{
+			name:       "empty header returns default",
+			acceptLang: "",
+			want:       locale.Default,
+		},
+		{
+			name:       "exact match",
+			acceptLang: "ru",
+			want:       "ru",
+		},
+		{
+			name:       "region subtag stripped",
+			acceptLang: "ru-RU",
+			want:       "ru",
+		},
+		{
+			name:       "full browser header picks first supported",
+			acceptLang: "ru-RU,ru;q=0.9,en-US;q=0.8,en;q=0.7",
+			want:       "ru",
+		},
+		{
+			name:       "unsupported first falls through to supported",
+			acceptLang: "xx-XX,ru;q=0.8",
+			want:       "ru",
+		},
+		{
+			name:       "completely unsupported returns default",
+			acceptLang: "xx-XX,yy-YY",
+			want:       locale.Default,
+		},
+		{
+			name:       "chinese region subtag",
+			acceptLang: "zh-CN,zh;q=0.9",
+			want:       "zh",
+		},
+		{
+			name:       "case insensitive",
+			acceptLang: "RU-RU",
+			want:       "ru",
+		},
+		{
+			name:       "whitespace around tag",
+			acceptLang: "  ru  ",
+			want:       "ru",
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			got := locale.Parse(tc.acceptLang)
+			if got != tc.want {
+				t.Errorf("Parse(%q) = %q, want %q", tc.acceptLang, got, tc.want)
+			}
+		})
+	}
+}
+
+func TestWithLangAndFromContext(t *testing.T) {
+	ctx := context.Background()
+
+	if got := locale.FromContext(ctx); got != locale.Default {
+		t.Errorf("FromContext on empty ctx = %q, want %q", got, locale.Default)
+	}
+
+	ctx = locale.WithLang(ctx, "ru")
+	if got := locale.FromContext(ctx); got != "ru" {
+		t.Errorf("FromContext after WithLang(ru) = %q, want %q", got, "ru")
+	}
+}
+
+func TestFromRequest(t *testing.T) {
+	req, _ := http.NewRequest(http.MethodGet, "/", nil)
+	req.Header.Set("Accept-Language", "es-ES,es;q=0.9")
+
+	if got := locale.FromRequest(req); got != "es" {
+		t.Errorf("FromRequest = %q, want %q", got, "es")
+	}
+}

backend/tests/middleware/auth_test.go

@@ -0,0 +1,193 @@
+package middleware_test
+
+import (
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+	"time"
+
+	"github.com/food-ai/backend/internal/middleware"
+	"github.com/golang-jwt/jwt/v5"
+)
+
+// testJWTClaims mirrors auth.Claims for test token generation without importing auth.
+type testJWTClaims struct {
+	UserID string `json:"user_id"`
+	Plan   string `json:"plan"`
+	jwt.RegisteredClaims
+}
+
+func generateTestToken(secret string, userID, plan string, duration time.Duration) string {
+	claims := testJWTClaims{
+		UserID: userID,
+		Plan:   plan,
+		RegisteredClaims: jwt.RegisteredClaims{
+			ExpiresAt: jwt.NewNumericDate(time.Now().Add(duration)),
+			IssuedAt:  jwt.NewNumericDate(time.Now()),
+		},
+	}
+	token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
+	tokenString, _ := token.SignedString([]byte(secret))
+	return tokenString
+}
+
+// testAccessValidator implements middleware.AccessTokenValidator for tests.
+type testAccessValidator struct {
+	secret string
+}
+
+func (v *testAccessValidator) ValidateAccessToken(tokenStr string) (*middleware.TokenClaims, error) {
+	token, parseError := jwt.ParseWithClaims(tokenStr, &testJWTClaims{}, func(t *jwt.Token) (interface{}, error) {
+		if _, ok := t.Method.(*jwt.SigningMethodHMAC); !ok {
+			return nil, fmt.Errorf("unexpected signing method")
+		}
+		return []byte(v.secret), nil
+	})
+	if parseError != nil {
+		return nil, parseError
+	}
+	claims, ok := token.Claims.(*testJWTClaims)
+	if !ok || !token.Valid {
+		return nil, fmt.Errorf("invalid token")
+	}
+	return &middleware.TokenClaims{UserID: claims.UserID, Plan: claims.Plan}, nil
+}
+
+// failingValidator always returns an error.
+type failingValidator struct{}
+
+func (v *failingValidator) ValidateAccessToken(tokenStr string) (*middleware.TokenClaims, error) {
+	return nil, fmt.Errorf("invalid token")
+}
+
+func TestAuth_ValidToken(t *testing.T) {
+	validator := &testAccessValidator{secret: "test-secret"}
+	token := generateTestToken("test-secret", "user-1", "free", 15*time.Minute)
+
+	handler := middleware.Auth(validator)(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		userID := middleware.UserIDFromCtx(r.Context())
+		if userID != "user-1" {
+			t.Errorf("expected user-1, got %s", userID)
+		}
+		plan := middleware.UserPlanFromCtx(r.Context())
+		if plan != "free" {
+			t.Errorf("expected free, got %s", plan)
+		}
+		w.WriteHeader(http.StatusOK)
+	}))
+
+	req := httptest.NewRequest("GET", "/", nil)
+	req.Header.Set("Authorization", "Bearer "+token)
+	rr := httptest.NewRecorder()
+
+	handler.ServeHTTP(rr, req)
+	if rr.Code != http.StatusOK {
+		t.Errorf("expected 200, got %d", rr.Code)
+	}
+}
+
+func TestAuth_MissingHeader(t *testing.T) {
+	validator := &testAccessValidator{secret: "test-secret"}
+
+	handler := middleware.Auth(validator)(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		t.Error("handler should not be called")
+	}))
+
+	req := httptest.NewRequest("GET", "/", nil)
+	rr := httptest.NewRecorder()
+
+	handler.ServeHTTP(rr, req)
+	if rr.Code != http.StatusUnauthorized {
+		t.Errorf("expected 401, got %d", rr.Code)
+	}
+}
+
+func TestAuth_InvalidBearerFormat(t *testing.T) {
+	validator := &testAccessValidator{secret: "test-secret"}
+
+	handler := middleware.Auth(validator)(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		t.Error("handler should not be called")
+	}))
+
+	req := httptest.NewRequest("GET", "/", nil)
+	req.Header.Set("Authorization", "Basic abc123")
+	rr := httptest.NewRecorder()
+
+	handler.ServeHTTP(rr, req)
+	if rr.Code != http.StatusUnauthorized {
+		t.Errorf("expected 401, got %d", rr.Code)
+	}
+}
+
+func TestAuth_ExpiredToken(t *testing.T) {
+	validator := &testAccessValidator{secret: "test-secret"}
+	token := generateTestToken("test-secret", "user-1", "free", -1*time.Second)
+
+	handler := middleware.Auth(validator)(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		t.Error("handler should not be called")
+	}))
+
+	req := httptest.NewRequest("GET", "/", nil)
+	req.Header.Set("Authorization", "Bearer "+token)
+	rr := httptest.NewRecorder()
+
+	handler.ServeHTTP(rr, req)
+	if rr.Code != http.StatusUnauthorized {
+		t.Errorf("expected 401, got %d", rr.Code)
+	}
+}
+
+func TestAuth_InvalidToken(t *testing.T) {
+	validator := &testAccessValidator{secret: "test-secret"}
+
+	handler := middleware.Auth(validator)(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		t.Error("handler should not be called")
+	}))
+
+	req := httptest.NewRequest("GET", "/", nil)
+	req.Header.Set("Authorization", "Bearer invalid-token")
+	rr := httptest.NewRecorder()
+
+	handler.ServeHTTP(rr, req)
+	if rr.Code != http.StatusUnauthorized {
+		t.Errorf("expected 401, got %d", rr.Code)
+	}
+}
+
+func TestAuth_PaidPlan(t *testing.T) {
+	validator := &testAccessValidator{secret: "test-secret"}
+	token := generateTestToken("test-secret", "user-1", "paid", 15*time.Minute)
+
+	handler := middleware.Auth(validator)(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		plan := middleware.UserPlanFromCtx(r.Context())
+		if plan != "paid" {
+			t.Errorf("expected paid, got %s", plan)
+		}
+		w.WriteHeader(http.StatusOK)
+	}))
+
+	req := httptest.NewRequest("GET", "/", nil)
+	req.Header.Set("Authorization", "Bearer "+token)
+	rr := httptest.NewRecorder()
+
+	handler.ServeHTTP(rr, req)
+	if rr.Code != http.StatusOK {
+		t.Errorf("expected 200, got %d", rr.Code)
+	}
+}
+
+func TestAuth_EmptyBearer(t *testing.T) {
+	handler := middleware.Auth(&failingValidator{})(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		t.Error("handler should not be called")
+	}))
+
+	req := httptest.NewRequest("GET", "/", nil)
+	req.Header.Set("Authorization", "Bearer ")
+	rr := httptest.NewRecorder()
+
+	handler.ServeHTTP(rr, req)
+	if rr.Code != http.StatusUnauthorized {
+		t.Errorf("expected 401, got %d", rr.Code)
+	}
+}

backend/tests/middleware/recovery_test.go

@@ -0,0 +1,51 @@
+package middleware_test
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/food-ai/backend/internal/middleware"
+)
+
+func TestRecovery_NoPanic(t *testing.T) {
+	handler := middleware.Recovery(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusOK)
+	}))
+
+	req := httptest.NewRequest("GET", "/", nil)
+	rr := httptest.NewRecorder()
+
+	handler.ServeHTTP(rr, req)
+	if rr.Code != http.StatusOK {
+		t.Errorf("expected 200, got %d", rr.Code)
+	}
+}
+
+func TestRecovery_CatchesPanic(t *testing.T) {
+	handler := middleware.Recovery(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		panic("test panic")
+	}))
+
+	req := httptest.NewRequest("GET", "/", nil)
+	rr := httptest.NewRecorder()
+
+	handler.ServeHTTP(rr, req)
+	if rr.Code != http.StatusInternalServerError {
+		t.Errorf("expected 500, got %d", rr.Code)
+	}
+}
+
+func TestRecovery_CatchesPanicWithError(t *testing.T) {
+	handler := middleware.Recovery(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		panic(42)
+	}))
+
+	req := httptest.NewRequest("GET", "/", nil)
+	rr := httptest.NewRecorder()
+
+	handler.ServeHTTP(rr, req)
+	if rr.Code != http.StatusInternalServerError {
+		t.Errorf("expected 500, got %d", rr.Code)
+	}
+}

backend/tests/middleware/request_id_test.go

@@ -0,0 +1,61 @@
+package middleware_test
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/food-ai/backend/internal/middleware"
+)
+
+func TestRequestID_GeneratesNew(t *testing.T) {
+	handler := middleware.RequestID(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		id := middleware.RequestIDFromCtx(r.Context())
+		if id == "" {
+			t.Error("expected non-empty request ID in context")
+		}
+	}))
+
+	req := httptest.NewRequest("GET", "/", nil)
+	rr := httptest.NewRecorder()
+
+	handler.ServeHTTP(rr, req)
+	if rr.Header().Get("X-Request-ID") == "" {
+		t.Error("expected X-Request-ID in response header")
+	}
+}
+
+func TestRequestID_PreservesExisting(t *testing.T) {
+	handler := middleware.RequestID(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		id := middleware.RequestIDFromCtx(r.Context())
+		if id != "existing-id" {
+			t.Errorf("expected 'existing-id', got %q", id)
+		}
+	}))
+
+	req := httptest.NewRequest("GET", "/", nil)
+	req.Header.Set("X-Request-ID", "existing-id")
+	rr := httptest.NewRecorder()
+
+	handler.ServeHTTP(rr, req)
+	if rr.Header().Get("X-Request-ID") != "existing-id" {
+		t.Error("expected preserved X-Request-ID")
+	}
+}
+
+func TestRequestID_UniquePerRequest(t *testing.T) {
+	var ids []string
+	handler := middleware.RequestID(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		ids = append(ids, middleware.RequestIDFromCtx(r.Context()))
+	}))
+
+	for i := 0; i < 3; i++ {
+		req := httptest.NewRequest("GET", "/", nil)
+		rr := httptest.NewRecorder()
+		handler.ServeHTTP(rr, req)
+	}
+
+	if ids[0] == ids[1] || ids[1] == ids[2] {
+		t.Error("expected unique IDs for each request")
+	}
+}

backend/tests/recipe/repository_integration_test.go

@@ -0,0 +1,36 @@
+//go:build integration
+
+package recipe_test
+
+import (
+	"context"
+	"testing"
+
+	"github.com/food-ai/backend/internal/recipe"
+	"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()
+
+	got, getError := repo.GetByID(ctx, "00000000-0000-0000-0000-000000000000")
+	if getError != nil {
+		t.Fatalf("unexpected error: %v", getError)
+	}
+	if got != nil {
+		t.Error("expected nil for non-existent ID")
+	}
+}
+
+func TestRecipeRepository_Count(t *testing.T) {
+	pool := testutil.SetupTestDB(t)
+	repo := recipe.NewRepository(pool)
+	ctx := context.Background()
+
+	_, countError := repo.Count(ctx)
+	if countError != nil {
+		t.Fatalf("count: %v", countError)
+	}
+}

backend/tests/user/calories_test.go

@@ -0,0 +1,113 @@
+package user_test
+
+import (
+	"testing"
+	"time"
+
+	"github.com/food-ai/backend/internal/user"
+)
+
+func ptr[T any](v T) *T { return &v }
+
+func TestAgeFromDOB_Nil(t *testing.T) {
+	if user.AgeFromDOB(nil) != nil {
+		t.Fatal("expected nil for nil input")
+	}
+}
+
+func TestAgeFromDOB_InvalidFormat(t *testing.T) {
+	s := "not-a-date"
+	if user.AgeFromDOB(&s) != nil {
+		t.Fatal("expected nil for invalid format")
+	}
+}
+
+func TestAgeFromDOB_ExactAge(t *testing.T) {
+	dob := time.Now().AddDate(-30, 0, 0).Format("2006-01-02")
+	age := user.AgeFromDOB(&dob)
+	if age == nil {
+		t.Fatal("expected non-nil result")
+	}
+	if *age != 30 {
+		t.Errorf("expected 30, got %d", *age)
+	}
+}
+
+func TestAgeFromDOB_BeforeBirthday(t *testing.T) {
+	// Birthday is one day in the future relative to today-25y, so age should be 24
+	now := time.Now()
+	dob := time.Date(now.Year()-25, now.Month(), now.Day()+1, 0, 0, 0, 0, time.UTC).Format("2006-01-02")
+	age := user.AgeFromDOB(&dob)
+	if age == nil {
+		t.Fatal("expected non-nil result")
+	}
+	if *age != 24 {
+		t.Errorf("expected 24, got %d", *age)
+	}
+}
+
+func TestCalculateDailyCalories_MaleMaintain(t *testing.T) {
+	cal := user.CalculateDailyCalories(ptr(180), ptr(80.0), ptr(30), ptr("male"), ptr("moderate"), ptr("maintain"))
+	if cal == nil {
+		t.Fatal("expected non-nil result")
+	}
+	// BMR = 10*80 + 6.25*180 - 5*30 + 5 = 800 + 1125 - 150 + 5 = 1780
+	// TDEE = 1780 * 1.55 = 2759
+	if *cal != 2759 {
+		t.Errorf("expected 2759, got %d", *cal)
+	}
+}
+
+func TestCalculateDailyCalories_FemaleLose(t *testing.T) {
+	cal := user.CalculateDailyCalories(ptr(165), ptr(60.0), ptr(25), ptr("female"), ptr("low"), ptr("lose"))
+	if cal == nil {
+		t.Fatal("expected non-nil result")
+	}
+	// BMR = 10*60 + 6.25*165 - 5*25 - 161 = 600 + 1031.25 - 125 - 161 = 1345.25
+	// TDEE = 1345.25 * 1.375 = 1849.72
+	// Goal: -500 = 1349.72 → 1350
+	if *cal != 1350 {
+		t.Errorf("expected 1350, got %d", *cal)
+	}
+}
+
+func TestCalculateDailyCalories_MaleGain(t *testing.T) {
+	cal := user.CalculateDailyCalories(ptr(175), ptr(70.0), ptr(28), ptr("male"), ptr("high"), ptr("gain"))
+	if cal == nil {
+		t.Fatal("expected non-nil result")
+	}
+	// BMR = 10*70 + 6.25*175 - 5*28 + 5 = 700 + 1093.75 - 140 + 5 = 1658.75
+	// TDEE = 1658.75 * 1.725 = 2861.34
+	// Goal: +300 = 3161.34 → 3161
+	if *cal != 3161 {
+		t.Errorf("expected 3161, got %d", *cal)
+	}
+}
+
+func TestCalculateDailyCalories_NilHeight(t *testing.T) {
+	cal := user.CalculateDailyCalories(nil, ptr(80.0), ptr(30), ptr("male"), ptr("moderate"), ptr("maintain"))
+	if cal != nil {
+		t.Fatal("expected nil when height is nil")
+	}
+}
+
+func TestCalculateDailyCalories_NilWeight(t *testing.T) {
+	cal := user.CalculateDailyCalories(ptr(180), nil, ptr(30), ptr("male"), ptr("moderate"), ptr("maintain"))
+	if cal != nil {
+		t.Fatal("expected nil when weight is nil")
+	}
+}
+
+func TestCalculateDailyCalories_InvalidGender(t *testing.T) {
+	cal := user.CalculateDailyCalories(ptr(180), ptr(80.0), ptr(30), ptr("other"), ptr("moderate"), ptr("maintain"))
+	if cal != nil {
+		t.Fatal("expected nil for invalid gender")
+	}
+}
+
+func TestCalculateDailyCalories_InvalidActivity(t *testing.T) {
+	cal := user.CalculateDailyCalories(ptr(180), ptr(80.0), ptr(30), ptr("male"), ptr("extreme"), ptr("maintain"))
+	if cal != nil {
+		t.Fatal("expected nil for invalid activity")
+	}
+}

backend/tests/user/repository_integration_test.go

@@ -0,0 +1,210 @@
+//go:build integration
+
+package user_test
+
+import (
+	"context"
+	"encoding/json"
+	"testing"
+	"time"
+
+	"github.com/food-ai/backend/internal/testutil"
+	"github.com/food-ai/backend/internal/user"
+)
+
+func TestRepository_UpsertByFirebaseUID_Insert(t *testing.T) {
+	pool := testutil.SetupTestDB(t)
+	repo := user.NewRepository(pool)
+	ctx := context.Background()
+
+	u, upsertError := repo.UpsertByFirebaseUID(ctx, "fb-123", "test@example.com", "Test User", "https://avatar.url")
+	if upsertError != nil {
+		t.Fatalf("unexpected error: %v", upsertError)
+	}
+	if u.FirebaseUID != "fb-123" {
+		t.Errorf("expected fb-123, got %s", u.FirebaseUID)
+	}
+	if u.Email != "test@example.com" {
+		t.Errorf("expected test@example.com, got %s", u.Email)
+	}
+	if u.Plan != "free" {
+		t.Errorf("expected free, got %s", u.Plan)
+	}
+}
+
+func TestRepository_UpsertByFirebaseUID_Update(t *testing.T) {
+	pool := testutil.SetupTestDB(t)
+	repo := user.NewRepository(pool)
+	ctx := context.Background()
+
+	_, _ = repo.UpsertByFirebaseUID(ctx, "fb-123", "old@example.com", "Old Name", "")
+	u, upsertError := repo.UpsertByFirebaseUID(ctx, "fb-123", "new@example.com", "New Name", "https://new-avatar.url")
+	if upsertError != nil {
+		t.Fatalf("unexpected error: %v", upsertError)
+	}
+	if u.Email != "new@example.com" {
+		t.Errorf("expected new email, got %s", u.Email)
+	}
+	// Name should not be overwritten if already set
+	if u.Name != "Old Name" {
+		t.Errorf("expected name to be preserved as 'Old Name', got %s", u.Name)
+	}
+}
+
+func TestRepository_GetByID(t *testing.T) {
+	pool := testutil.SetupTestDB(t)
+	repo := user.NewRepository(pool)
+	ctx := context.Background()
+
+	created, _ := repo.UpsertByFirebaseUID(ctx, "fb-get", "get@example.com", "Get User", "")
+	u, getError := repo.GetByID(ctx, created.ID)
+	if getError != nil {
+		t.Fatalf("unexpected error: %v", getError)
+	}
+	if u.ID != created.ID {
+		t.Errorf("expected %s, got %s", created.ID, u.ID)
+	}
+}
+
+func TestRepository_GetByID_NotFound(t *testing.T) {
+	pool := testutil.SetupTestDB(t)
+	repo := user.NewRepository(pool)
+	ctx := context.Background()
+
+	_, getError := repo.GetByID(ctx, "00000000-0000-0000-0000-000000000000")
+	if getError == nil {
+		t.Fatal("expected error for non-existent user")
+	}
+}
+
+func TestRepository_Update(t *testing.T) {
+	pool := testutil.SetupTestDB(t)
+	repo := user.NewRepository(pool)
+	ctx := context.Background()
+
+	created, _ := repo.UpsertByFirebaseUID(ctx, "fb-upd", "upd@example.com", "Update User", "")
+	height := 180
+	u, updateError := repo.Update(ctx, created.ID, user.UpdateProfileRequest{HeightCM: &height})
+	if updateError != nil {
+		t.Fatalf("unexpected error: %v", updateError)
+	}
+	if u.HeightCM == nil || *u.HeightCM != 180 {
+		t.Errorf("expected height 180, got %v", u.HeightCM)
+	}
+}
+
+func TestRepository_Update_MultipleFields(t *testing.T) {
+	pool := testutil.SetupTestDB(t)
+	repo := user.NewRepository(pool)
+	ctx := context.Background()
+
+	created, _ := repo.UpsertByFirebaseUID(ctx, "fb-multi", "multi@example.com", "Multi User", "")
+	height := 175
+	weight := 70.5
+	dob := "2001-03-09"
+	gender := "male"
+	activity := "moderate"
+	goal := "maintain"
+	u, updateError := repo.Update(ctx, created.ID, user.UpdateProfileRequest{
+		HeightCM:    &height,
+		WeightKG:    &weight,
+		DateOfBirth: &dob,
+		Gender:      &gender,
+		Activity:    &activity,
+		Goal:        &goal,
+	})
+	if updateError != nil {
+		t.Fatalf("unexpected error: %v", updateError)
+	}
+	if u.HeightCM == nil || *u.HeightCM != 175 {
+		t.Errorf("expected 175, got %v", u.HeightCM)
+	}
+	if u.WeightKG == nil || *u.WeightKG != 70.5 {
+		t.Errorf("expected 70.5, got %v", u.WeightKG)
+	}
+}
+
+func TestRepository_Update_Preferences(t *testing.T) {
+	pool := testutil.SetupTestDB(t)
+	repo := user.NewRepository(pool)
+	ctx := context.Background()
+
+	created, _ := repo.UpsertByFirebaseUID(ctx, "fb-prefs", "prefs@example.com", "Prefs User", "")
+	prefs := json.RawMessage(`{"cuisines":["russian","asian"]}`)
+	u, updateError := repo.Update(ctx, created.ID, user.UpdateProfileRequest{Preferences: &prefs})
+	if updateError != nil {
+		t.Fatalf("unexpected error: %v", updateError)
+	}
+	var preferences map[string]interface{}
+	json.Unmarshal(u.Preferences, &preferences)
+	if preferences["cuisines"] == nil {
+		t.Error("expected cuisines in preferences")
+	}
+}
+
+func TestRepository_SetAndFindRefreshToken(t *testing.T) {
+	pool := testutil.SetupTestDB(t)
+	repo := user.NewRepository(pool)
+	ctx := context.Background()
+
+	created, _ := repo.UpsertByFirebaseUID(ctx, "fb-token", "token@example.com", "Token User", "")
+	setError := repo.SetRefreshToken(ctx, created.ID, "refresh-token-123", time.Now().Add(24*time.Hour))
+	if setError != nil {
+		t.Fatalf("unexpected error setting token: %v", setError)
+	}
+
+	u, findError := repo.FindByRefreshToken(ctx, "refresh-token-123")
+	if findError != nil {
+		t.Fatalf("unexpected error finding by token: %v", findError)
+	}
+	if u.ID != created.ID {
+		t.Errorf("expected %s, got %s", created.ID, u.ID)
+	}
+}
+
+func TestRepository_FindByRefreshToken_Expired(t *testing.T) {
+	pool := testutil.SetupTestDB(t)
+	repo := user.NewRepository(pool)
+	ctx := context.Background()
+
+	created, _ := repo.UpsertByFirebaseUID(ctx, "fb-expired", "expired@example.com", "Expired User", "")
+	_ = repo.SetRefreshToken(ctx, created.ID, "expired-token", time.Now().Add(-1*time.Hour))
+
+	_, findError := repo.FindByRefreshToken(ctx, "expired-token")
+	if findError == nil {
+		t.Fatal("expected error for expired token")
+	}
+}
+
+func TestRepository_ClearRefreshToken(t *testing.T) {
+	pool := testutil.SetupTestDB(t)
+	repo := user.NewRepository(pool)
+	ctx := context.Background()
+
+	created, _ := repo.UpsertByFirebaseUID(ctx, "fb-clear", "clear@example.com", "Clear User", "")
+	_ = repo.SetRefreshToken(ctx, created.ID, "token-to-clear", time.Now().Add(24*time.Hour))
+	clearError := repo.ClearRefreshToken(ctx, created.ID)
+	if clearError != nil {
+		t.Fatalf("unexpected error: %v", clearError)
+	}
+
+	_, findError := repo.FindByRefreshToken(ctx, "token-to-clear")
+	if findError == nil {
+		t.Fatal("expected error after clearing token")
+	}
+}
+
+func TestRepository_Update_NoFields(t *testing.T) {
+	pool := testutil.SetupTestDB(t)
+	repo := user.NewRepository(pool)
+	ctx := context.Background()
+
+	created, _ := repo.UpsertByFirebaseUID(ctx, "fb-noop", "noop@example.com", "Noop User", "")
+	u, updateError := repo.Update(ctx, created.ID, user.UpdateProfileRequest{})
+	if updateError != nil {
+		t.Fatalf("unexpected error: %v", updateError)
+	}
+	if u.ID != created.ID {
+		t.Errorf("expected %s, got %s", created.ID, u.ID)
+	}
+}

backend/tests/user/service_test.go

@@ -0,0 +1,262 @@
+package user_test
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"testing"
+	"time"
+
+	"github.com/food-ai/backend/internal/user"
+)
+
+func ptrStr(s string) *string     { return &s }
+func ptrInt(i int) *int           { return &i }
+func ptrFloat(f float64) *float64 { return &f }
+
+// mockUserRepo is an in-test mock implementing user.UserRepository.
+type mockUserRepo struct {
+	getByIDFn             func(ctx context.Context, id string) (*user.User, error)
+	updateFn              func(ctx context.Context, id string, req user.UpdateProfileRequest) (*user.User, error)
+	updateInTxFn          func(ctx context.Context, id string, profileReq user.UpdateProfileRequest, caloriesReq *user.UpdateProfileRequest) (*user.User, error)
+	upsertByFirebaseUIDFn func(ctx context.Context, uid, email, name, avatarURL string) (*user.User, error)
+	setRefreshTokenFn     func(ctx context.Context, id, token string, expiresAt time.Time) error
+	findByRefreshTokenFn  func(ctx context.Context, token string) (*user.User, error)
+	clearRefreshTokenFn   func(ctx context.Context, id string) error
+}
+
+func (m *mockUserRepo) UpsertByFirebaseUID(ctx context.Context, uid, email, name, avatarURL string) (*user.User, error) {
+	return m.upsertByFirebaseUIDFn(ctx, uid, email, name, avatarURL)
+}
+func (m *mockUserRepo) GetByID(ctx context.Context, id string) (*user.User, error) {
+	return m.getByIDFn(ctx, id)
+}
+func (m *mockUserRepo) Update(ctx context.Context, id string, req user.UpdateProfileRequest) (*user.User, error) {
+	return m.updateFn(ctx, id, req)
+}
+func (m *mockUserRepo) UpdateInTx(ctx context.Context, id string, profileReq user.UpdateProfileRequest, caloriesReq *user.UpdateProfileRequest) (*user.User, error) {
+	return m.updateInTxFn(ctx, id, profileReq, caloriesReq)
+}
+func (m *mockUserRepo) SetRefreshToken(ctx context.Context, id, token string, expiresAt time.Time) error {
+	return m.setRefreshTokenFn(ctx, id, token, expiresAt)
+}
+func (m *mockUserRepo) FindByRefreshToken(ctx context.Context, token string) (*user.User, error) {
+	return m.findByRefreshTokenFn(ctx, token)
+}
+func (m *mockUserRepo) ClearRefreshToken(ctx context.Context, id string) error {
+	return m.clearRefreshTokenFn(ctx, id)
+}
+
+func TestGetProfile_Success(t *testing.T) {
+	repo := &mockUserRepo{
+		getByIDFn: func(ctx context.Context, id string) (*user.User, error) {
+			return &user.User{ID: id, Email: "test@example.com", Plan: "free"}, nil
+		},
+	}
+	svc := user.NewService(repo)
+
+	u, getError := svc.GetProfile(context.Background(), "user-1")
+	if getError != nil {
+		t.Fatalf("unexpected error: %v", getError)
+	}
+	if u.ID != "user-1" {
+		t.Errorf("expected user-1, got %s", u.ID)
+	}
+}
+
+func TestGetProfile_NotFound(t *testing.T) {
+	repo := &mockUserRepo{
+		getByIDFn: func(ctx context.Context, id string) (*user.User, error) {
+			return nil, fmt.Errorf("not found")
+		},
+	}
+	svc := user.NewService(repo)
+
+	_, getError := svc.GetProfile(context.Background(), "nonexistent")
+	if getError == nil {
+		t.Fatal("expected error")
+	}
+}
+
+func TestUpdateProfile_NameOnly(t *testing.T) {
+	repo := &mockUserRepo{
+		updateFn: func(ctx context.Context, id string, req user.UpdateProfileRequest) (*user.User, error) {
+			return &user.User{ID: id, Name: *req.Name, Plan: "free"}, nil
+		},
+	}
+	svc := user.NewService(repo)
+
+	u, updateError := svc.UpdateProfile(context.Background(), "user-1", user.UpdateProfileRequest{Name: ptrStr("New Name")})
+	if updateError != nil {
+		t.Fatalf("unexpected error: %v", updateError)
+	}
+	if u.Name != "New Name" {
+		t.Errorf("expected 'New Name', got %q", u.Name)
+	}
+}
+
+func TestUpdateProfile_WithCaloriesRecalculation(t *testing.T) {
+	dob := time.Now().AddDate(-30, 0, 0).Format("2006-01-02")
+	profileReq := user.UpdateProfileRequest{
+		HeightCM:    ptrInt(180),
+		WeightKG:    ptrFloat(80),
+		DateOfBirth: &dob,
+		Gender:      ptrStr("male"),
+		Activity:    ptrStr("moderate"),
+		Goal:        ptrStr("maintain"),
+	}
+	finalUser := &user.User{
+		ID:            "user-1",
+		HeightCM:      ptrInt(180),
+		WeightKG:      ptrFloat(80),
+		DateOfBirth:   &dob,
+		Gender:        ptrStr("male"),
+		Activity:      ptrStr("moderate"),
+		Goal:          ptrStr("maintain"),
+		DailyCalories: ptrInt(2759),
+		Plan:          "free",
+	}
+
+	repo := &mockUserRepo{
+		// Service calls GetByID first to merge current values for calorie calculation
+		getByIDFn: func(ctx context.Context, id string) (*user.User, error) {
+			return &user.User{ID: id, Plan: "free"}, nil
+		},
+		updateInTxFn: func(ctx context.Context, id string, pReq user.UpdateProfileRequest, cReq *user.UpdateProfileRequest) (*user.User, error) {
+			if cReq == nil {
+				t.Error("expected caloriesReq to be non-nil")
+			} else if *cReq.DailyCalories != 2759 {
+				t.Errorf("expected calories 2759, got %d", *cReq.DailyCalories)
+			}
+			return finalUser, nil
+		},
+	}
+	svc := user.NewService(repo)
+
+	u, updateError := svc.UpdateProfile(context.Background(), "user-1", profileReq)
+	if updateError != nil {
+		t.Fatalf("unexpected error: %v", updateError)
+	}
+	if u.DailyCalories == nil {
+		t.Fatal("expected daily_calories to be set")
+	}
+	if *u.DailyCalories != 2759 {
+		t.Errorf("expected 2759, got %d", *u.DailyCalories)
+	}
+}
+
+func TestUpdateProfile_InvalidHeight_TooLow(t *testing.T) {
+	svc := user.NewService(&mockUserRepo{})
+
+	_, validationError := svc.UpdateProfile(context.Background(), "user-1", user.UpdateProfileRequest{HeightCM: ptrInt(50)})
+	if validationError == nil {
+		t.Fatal("expected validation error")
+	}
+}
+
+func TestUpdateProfile_InvalidHeight_TooHigh(t *testing.T) {
+	svc := user.NewService(&mockUserRepo{})
+
+	_, validationError := svc.UpdateProfile(context.Background(), "user-1", user.UpdateProfileRequest{HeightCM: ptrInt(300)})
+	if validationError == nil {
+		t.Fatal("expected validation error")
+	}
+}
+
+func TestUpdateProfile_InvalidWeight_TooLow(t *testing.T) {
+	svc := user.NewService(&mockUserRepo{})
+
+	_, validationError := svc.UpdateProfile(context.Background(), "user-1", user.UpdateProfileRequest{WeightKG: ptrFloat(10)})
+	if validationError == nil {
+		t.Fatal("expected validation error")
+	}
+}
+
+func TestUpdateProfile_InvalidWeight_TooHigh(t *testing.T) {
+	svc := user.NewService(&mockUserRepo{})
+
+	_, validationError := svc.UpdateProfile(context.Background(), "user-1", user.UpdateProfileRequest{WeightKG: ptrFloat(400)})
+	if validationError == nil {
+		t.Fatal("expected validation error")
+	}
+}
+
+func TestUpdateProfile_InvalidDOB_TooRecent(t *testing.T) {
+	svc := user.NewService(&mockUserRepo{})
+	dob := time.Now().AddDate(-5, 0, 0).Format("2006-01-02")
+
+	_, validationError := svc.UpdateProfile(context.Background(), "user-1", user.UpdateProfileRequest{DateOfBirth: &dob})
+	if validationError == nil {
+		t.Fatal("expected validation error")
+	}
+}
+
+func TestUpdateProfile_InvalidDOB_TooOld(t *testing.T) {
+	svc := user.NewService(&mockUserRepo{})
+	dob := time.Now().AddDate(-150, 0, 0).Format("2006-01-02")
+
+	_, validationError := svc.UpdateProfile(context.Background(), "user-1", user.UpdateProfileRequest{DateOfBirth: &dob})
+	if validationError == nil {
+		t.Fatal("expected validation error")
+	}
+}
+
+func TestUpdateProfile_InvalidDOB_BadFormat(t *testing.T) {
+	svc := user.NewService(&mockUserRepo{})
+	dob := "not-a-date"
+
+	_, validationError := svc.UpdateProfile(context.Background(), "user-1", user.UpdateProfileRequest{DateOfBirth: &dob})
+	if validationError == nil {
+		t.Fatal("expected validation error")
+	}
+}
+
+func TestUpdateProfile_InvalidGender(t *testing.T) {
+	svc := user.NewService(&mockUserRepo{})
+
+	_, validationError := svc.UpdateProfile(context.Background(), "user-1", user.UpdateProfileRequest{Gender: ptrStr("other")})
+	if validationError == nil {
+		t.Fatal("expected validation error")
+	}
+}
+
+func TestUpdateProfile_InvalidActivity(t *testing.T) {
+	svc := user.NewService(&mockUserRepo{})
+
+	_, validationError := svc.UpdateProfile(context.Background(), "user-1", user.UpdateProfileRequest{Activity: ptrStr("extreme")})
+	if validationError == nil {
+		t.Fatal("expected validation error")
+	}
+}
+
+func TestUpdateProfile_InvalidGoal(t *testing.T) {
+	svc := user.NewService(&mockUserRepo{})
+
+	_, validationError := svc.UpdateProfile(context.Background(), "user-1", user.UpdateProfileRequest{Goal: ptrStr("bulk")})
+	if validationError == nil {
+		t.Fatal("expected validation error")
+	}
+}
+
+func TestUpdateProfile_Preferences(t *testing.T) {
+	prefs := json.RawMessage(`{"cuisines":["russian"]}`)
+	repo := &mockUserRepo{
+		updateFn: func(ctx context.Context, id string, req user.UpdateProfileRequest) (*user.User, error) {
+			return &user.User{
+				ID:          id,
+				Plan:        "free",
+				Preferences: *req.Preferences,
+				UpdatedAt:   time.Now(),
+			}, nil
+		},
+	}
+	svc := user.NewService(repo)
+
+	u, updateError := svc.UpdateProfile(context.Background(), "user-1", user.UpdateProfileRequest{Preferences: &prefs})
+	if updateError != nil {
+		t.Fatalf("unexpected error: %v", updateError)
+	}
+	if string(u.Preferences) != `{"cuisines":["russian"]}` {
+		t.Errorf("unexpected preferences: %s", u.Preferences)
+	}
+}