feat(notify): Phase 2.5 — Notifier Telegram + Resend email

- internal/notify: Telegram (POST /sendMessage) et Resend email (POST /emails)
- Credentials lus depuis env vars (telegramBaseURL/resendBaseURL overridables en test)
- No-op gracieux quand token/key absents
- 5 tests unitaires avec httptest.Server

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

internal/notify/notifier_test.go

@@ -0,0 +1,123 @@
+package notify
+
+import (
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"forge.secuaas.ovh/olivier/claude-failover/internal/config"
+)
+
+// TestTelegramNoop verifies that an unconfigured notifier is a safe no-op.
+func TestTelegramNoop(t *testing.T) {
+	n := &Notifier{}
+	if err := n.Telegram("hello"); err != nil {
+		t.Errorf("expected nil error for empty token, got %v", err)
+	}
+}
+
+// TestEmailNoop verifies that an unconfigured notifier is a safe no-op.
+func TestEmailNoop(t *testing.T) {
+	n := &Notifier{}
+	if err := n.Email("subject", "<p>body</p>"); err != nil {
+		t.Errorf("expected nil error for empty API key, got %v", err)
+	}
+}
+
+// TestNewFromConfig verifies that New reads credentials from env vars.
+func TestNewFromConfig(t *testing.T) {
+	t.Setenv("TEST_TG_TOKEN", "my-token")
+	t.Setenv("TEST_TG_CHAT", "9999")
+	t.Setenv("TEST_EMAIL", "ops@example.com")
+
+	cfg := &config.Config{
+		Notifications: config.NotificationsConfig{
+			TelegramTokenEnv:  "TEST_TG_TOKEN",
+			TelegramChatIDEnv: "TEST_TG_CHAT",
+			NotifyEmailEnv:    "TEST_EMAIL",
+		},
+	}
+	n := New(cfg)
+	if n.telegramToken != "my-token" {
+		t.Errorf("expected token my-token, got %q", n.telegramToken)
+	}
+	if n.telegramChatID != "9999" {
+		t.Errorf("expected chatID 9999, got %q", n.telegramChatID)
+	}
+	if n.notifyEmail != "ops@example.com" {
+		t.Errorf("expected email ops@example.com, got %q", n.notifyEmail)
+	}
+}
+
+// TestTelegramHTTP verifies the actual HTTP body sent to Telegram.
+func TestTelegramHTTP(t *testing.T) {
+	var gotBody map[string]string
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		json.NewDecoder(r.Body).Decode(&gotBody)
+		w.WriteHeader(200)
+		w.Write([]byte(`{"ok":true}`))
+	}))
+	defer srv.Close()
+
+	n := &Notifier{
+		telegramToken:   "tok",
+		telegramChatID:  "42",
+		httpClient:      srv.Client(),
+		telegramBaseURL: srv.URL,
+	}
+	if err := n.Telegram("test message"); err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if gotBody["text"] != "test message" {
+		t.Errorf("expected text 'test message', got %q", gotBody["text"])
+	}
+	if gotBody["chat_id"] != "42" {
+		t.Errorf("expected chat_id 42, got %q", gotBody["chat_id"])
+	}
+}
+
+// TestEmailHTTP verifies the HTTP body sent to Resend.
+func TestEmailHTTP(t *testing.T) {
+	var gotBody map[string]interface{}
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		json.NewDecoder(r.Body).Decode(&gotBody)
+		if r.Header.Get("Authorization") != "Bearer test-key" {
+			t.Errorf("unexpected Authorization header: %q", r.Header.Get("Authorization"))
+		}
+		w.WriteHeader(201)
+		w.Write([]byte(`{"id":"msg-123"}`))
+	}))
+	defer srv.Close()
+
+	n := &Notifier{
+		resendAPIKey:  "test-key",
+		notifyEmail:   "user@example.com",
+		httpClient:    srv.Client(),
+		resendBaseURL: srv.URL,
+	}
+	if err := n.Email("Alert", "<p>something happened</p>"); err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if gotBody["subject"] != "Alert" {
+		t.Errorf("expected subject Alert, got %v", gotBody["subject"])
+	}
+}
+
+// TestTelegramHTTPError propagates non-2xx status as error.
+func TestTelegramHTTPError(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(429)
+	}))
+	defer srv.Close()
+
+	n := &Notifier{
+		telegramToken:   "tok",
+		telegramChatID:  "1",
+		httpClient:      srv.Client(),
+		telegramBaseURL: srv.URL,
+	}
+	if err := n.Telegram("msg"); err == nil {
+		t.Error("expected error on HTTP 429, got nil")
+	}
+}