fix: improve telegram channel connectivity

internal/service/telegram_api_test.go

@@ -0,0 +1,34 @@
+package service
+
+import (
+	"errors"
+	"strings"
+	"testing"
+)
+
+func TestTelegramMethodURLUsesCustomAPIBase(t *testing.T) {
+	got, err := telegramMethodURL(map[string]string{
+		"api_base_url": "https://tg.example.com/",
+	}, "123456:ABC-def", "sendMessage")
+	if err != nil {
+		t.Fatalf("telegramMethodURL returned error: %v", err)
+	}
+	want := "https://tg.example.com/bot123456:ABC-def/sendMessage"
+	if got != want {
+		t.Fatalf("got %q, want %q", got, want)
+	}
+}
+
+func TestSanitizeTelegramErrorRedactsBotToken(t *testing.T) {
+	err := sanitizeTelegramError(errors.New(`Post "https://api.telegram.org/bot123456:SECRET/sendMessage": context deadline exceeded`))
+	if err == nil {
+		t.Fatal("expected error")
+	}
+	msg := err.Error()
+	if strings.Contains(msg, "SECRET") || strings.Contains(msg, "123456:") {
+		t.Fatalf("telegram token leaked in error: %s", msg)
+	}
+	if !strings.Contains(msg, "timeout") {
+		t.Fatalf("expected timeout hint, got: %s", msg)
+	}
+}