Coverage priorities 1-5: test pure functions, extract interfaces, mock-based handler tests

- Priority 1: Test NewSendEmailTask + NewSendPushTask (5 tests)
- Priority 2: Test customHTTPErrorHandler — all 15+ branches (21 tests)
- Priority 3: Extract Enqueuer interface + payload builders in worker pkg (5 tests)
- Priority 4: Extract ClassifyFile/ComputeRelPath in migrate-encrypt (6 tests)
- Priority 5: Define Handler interfaces, refactor to accept them, mock-based tests (14 tests)
- Fix .gitignore: /worker instead of worker to stop ignoring internal/worker/

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

internal/i18n/i18n_test.go

@@ -0,0 +1,211 @@
+package i18n
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/labstack/echo/v4"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestInit(t *testing.T) {
+	err := Init()
+	require.NoError(t, err)
+	assert.NotNil(t, Bundle)
+}
+
+func TestTSimple_EnglishKnownKey(t *testing.T) {
+	require.NoError(t, Init())
+
+	localizer := NewLocalizer("en")
+	msg := TSimple(localizer, "error.task_not_found")
+	assert.Equal(t, "Task not found", msg)
+}
+
+func TestTSimple_SpanishKnownKey(t *testing.T) {
+	require.NoError(t, Init())
+
+	localizer := NewLocalizer("es")
+	msg := TSimple(localizer, "error.invalid_credentials")
+	assert.Equal(t, "Credenciales no validas", msg)
+}
+
+func TestT_WithTemplateData(t *testing.T) {
+	require.NoError(t, Init())
+
+	localizer := NewLocalizer("en")
+	msg := T(localizer, "message.tasks_report_sent", map[string]interface{}{
+		"Email": "test@example.com",
+	})
+	assert.Contains(t, msg, "test@example.com")
+}
+
+func TestTSimple_UnknownKeyReturnsKey(t *testing.T) {
+	require.NoError(t, Init())
+
+	localizer := NewLocalizer("en")
+	key := "error.nonexistent_key_that_does_not_exist"
+	msg := TSimple(localizer, key)
+	assert.Equal(t, key, msg)
+}
+
+func TestTSimple_FallbackToEnglish(t *testing.T) {
+	require.NoError(t, Init())
+
+	// Use a language that may not have all translations — fallback to English
+	localizer := NewLocalizer("xx", "en")
+	msg := TSimple(localizer, "error.task_not_found")
+	assert.Equal(t, "Task not found", msg)
+}
+
+func TestT_NilLocalizer_UsesDefault(t *testing.T) {
+	require.NoError(t, Init())
+
+	msg := T(nil, "error.task_not_found", nil)
+	assert.Equal(t, "Task not found", msg)
+}
+
+func TestNewLocalizer(t *testing.T) {
+	require.NoError(t, Init())
+
+	localizer := NewLocalizer("en")
+	assert.NotNil(t, localizer)
+}
+
+func TestParseAcceptLanguage(t *testing.T) {
+	tests := []struct {
+		name     string
+		header   string
+		expected []string
+	}{
+		{"empty returns default", "", []string{"en"}},
+		{"english", "en-US,en;q=0.9", []string{"en", "en"}},
+		{"spanish first", "es,en;q=0.5", []string{"es", "en"}},
+		{"unsupported returns default", "xx-YY", []string{"en"}},
+		{"french", "fr-FR,fr;q=0.9,en;q=0.5", []string{"fr", "fr", "en"}},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			result := parseAcceptLanguage(tc.header)
+			assert.Equal(t, tc.expected, result)
+		})
+	}
+}
+
+func TestMatchLocale(t *testing.T) {
+	tests := []struct {
+		name     string
+		langs    []string
+		expected string
+	}{
+		{"finds supported", []string{"es", "en"}, "es"},
+		{"first match wins", []string{"fr", "de"}, "fr"},
+		{"unsupported returns default", []string{"xx"}, "en"},
+		{"empty returns default", []string{}, "en"},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			result := matchLocale(tc.langs)
+			assert.Equal(t, tc.expected, result)
+		})
+	}
+}
+
+func TestMiddleware_SetsLocalizerAndLocale(t *testing.T) {
+	require.NoError(t, Init())
+
+	e := echo.New()
+	req := httptest.NewRequest(http.MethodGet, "/", nil)
+	req.Header.Set("Accept-Language", "es,en;q=0.5")
+	rec := httptest.NewRecorder()
+	c := e.NewContext(req, rec)
+
+	handler := Middleware()(func(c echo.Context) error {
+		// Verify localizer is set
+		localizer := GetLocalizer(c)
+		assert.NotNil(t, localizer)
+
+		// Verify locale is set
+		locale := GetLocale(c)
+		assert.Equal(t, "es", locale)
+
+		return nil
+	})
+
+	err := handler(c)
+	assert.NoError(t, err)
+}
+
+func TestGetLocalizer_NoContextValue_ReturnsDefault(t *testing.T) {
+	require.NoError(t, Init())
+
+	e := echo.New()
+	req := httptest.NewRequest(http.MethodGet, "/", nil)
+	rec := httptest.NewRecorder()
+	c := e.NewContext(req, rec)
+
+	localizer := GetLocalizer(c)
+	assert.NotNil(t, localizer)
+}
+
+func TestGetLocale_NoContextValue_ReturnsDefault(t *testing.T) {
+	e := echo.New()
+	req := httptest.NewRequest(http.MethodGet, "/", nil)
+	rec := httptest.NewRecorder()
+	c := e.NewContext(req, rec)
+
+	locale := GetLocale(c)
+	assert.Equal(t, "en", locale)
+}
+
+func TestLocalizedMessage(t *testing.T) {
+	require.NoError(t, Init())
+
+	e := echo.New()
+	req := httptest.NewRequest(http.MethodGet, "/", nil)
+	req.Header.Set("Accept-Language", "en")
+	rec := httptest.NewRecorder()
+	c := e.NewContext(req, rec)
+
+	// Set up localizer through middleware
+	handler := Middleware()(func(c echo.Context) error {
+		msg := LocalizedMessage(c, "error.task_not_found")
+		assert.Equal(t, "Task not found", msg)
+		return nil
+	})
+
+	err := handler(c)
+	assert.NoError(t, err)
+}
+
+func TestLocalizedMessageWithData(t *testing.T) {
+	require.NoError(t, Init())
+
+	e := echo.New()
+	req := httptest.NewRequest(http.MethodGet, "/", nil)
+	req.Header.Set("Accept-Language", "en")
+	rec := httptest.NewRecorder()
+	c := e.NewContext(req, rec)
+
+	handler := Middleware()(func(c echo.Context) error {
+		msg := LocalizedMessageWithData(c, "message.tasks_report_sent", map[string]interface{}{
+			"Email": "user@example.com",
+		})
+		assert.Contains(t, msg, "user@example.com")
+		return nil
+	})
+
+	err := handler(c)
+	assert.NoError(t, err)
+}
+
+func TestSupportedLanguages(t *testing.T) {
+	assert.Contains(t, SupportedLanguages, "en")
+	assert.Contains(t, SupportedLanguages, "es")
+	assert.Contains(t, SupportedLanguages, "fr")
+	assert.Equal(t, "en", DefaultLanguage)
+}