test(message): erp-message 从 45 增至 69 个单元测试 — DND 时间窗 + TransactionError + model_to_resp

- module.rs: 提取 is_in_dnd_window 纯函数 + 14 个 DND 时间窗测试（正常范围/跨午夜/边界）
- error.rs: 2 个 TransactionError 转换测试（Connection/Transaction）
- message_service: 2 个 model_to_resp 字段映射测试
- template_service: 1 个 model_to_resp 字段映射测试
- subscription_service: 1 个 model_to_resp 字段映射测试

crates/erp-message/src/module.rs

@@ -171,7 +171,11 @@ async fn should_skip_for_dnd(
     };
     let now = chrono::Local::now();
     let now_time = now.format("%H:%M").to_string();
-    // DND 窗口比较（支持跨午夜，如 22:00-08:00）
+    is_in_dnd_window(&now_time, &start, &end)
+}
+
+/// 判断当前时间是否在 DND 窗口内。支持跨午夜窗口（如 22:00-06:00）。
+pub(crate) fn is_in_dnd_window(now_time: &str, start: &str, end: &str) -> bool {
     if start <= end {
         now_time >= start && now_time < end
     } else {
@@ -602,3 +606,89 @@ async fn handle_workflow_event(
     }
     Ok(())
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    // ---- DND 时间窗逻辑 ----
+
+    #[test]
+    fn dnd_normal_range_inside() {
+        // 09:00-17:00，当前 12:00 → 在窗口内
+        assert!(is_in_dnd_window("12:00", "09:00", "17:00"));
+    }
+
+    #[test]
+    fn dnd_normal_range_before() {
+        // 09:00-17:00，当前 08:00 → 不在窗口内
+        assert!(!is_in_dnd_window("08:00", "09:00", "17:00"));
+    }
+
+    #[test]
+    fn dnd_normal_range_after() {
+        // 09:00-17:00，当前 18:00 → 不在窗口内
+        assert!(!is_in_dnd_window("18:00", "09:00", "17:00"));
+    }
+
+    #[test]
+    fn dnd_normal_range_at_start() {
+        // 09:00-17:00，当前 09:00 → 在窗口内（>= start）
+        assert!(is_in_dnd_window("09:00", "09:00", "17:00"));
+    }
+
+    #[test]
+    fn dnd_normal_range_at_end() {
+        // 09:00-17:00，当前 17:00 → 不在窗口内（< end 排除了 end 本身）
+        assert!(!is_in_dnd_window("17:00", "09:00", "17:00"));
+    }
+
+    #[test]
+    fn dnd_cross_midnight_night_time() {
+        // 22:00-06:00，当前 23:30 → 在窗口内
+        assert!(is_in_dnd_window("23:30", "22:00", "06:00"));
+    }
+
+    #[test]
+    fn dnd_cross_midnight_early_morning() {
+        // 22:00-06:00，当前 03:00 → 在窗口内
+        assert!(is_in_dnd_window("03:00", "22:00", "06:00"));
+    }
+
+    #[test]
+    fn dnd_cross_midnight_daytime() {
+        // 22:00-06:00，当前 14:00 → 不在窗口内
+        assert!(!is_in_dnd_window("14:00", "22:00", "06:00"));
+    }
+
+    #[test]
+    fn dnd_cross_midnight_at_start() {
+        assert!(is_in_dnd_window("22:00", "22:00", "06:00"));
+    }
+
+    #[test]
+    fn dnd_cross_midnight_at_end() {
+        assert!(!is_in_dnd_window("06:00", "22:00", "06:00"));
+    }
+
+    #[test]
+    fn dnd_cross_midnight_just_before_end() {
+        assert!(is_in_dnd_window("05:59", "22:00", "06:00"));
+    }
+
+    #[test]
+    fn dnd_same_start_end_always_in() {
+        // start == end 意味着 start <= end，所以 now >= start && now < end
+        // "00:00" >= "00:00" && "00:00" < "00:00" → false
+        assert!(!is_in_dnd_window("00:00", "12:00", "12:00"));
+        // "15:00" >= "12:00" && "15:00" < "12:00" → false
+        assert!(!is_in_dnd_window("15:00", "12:00", "12:00"));
+    }
+
+    #[test]
+    fn dnd_single_minute_window() {
+        // 23:59-00:00（跨午夜 1 分钟）
+        assert!(is_in_dnd_window("23:59", "23:59", "00:00"));
+        assert!(!is_in_dnd_window("00:00", "23:59", "00:00"));
+    }
+}