Fix unused function warning for parse_ical_datetime

- Add #[cfg(test)] attribute to mark function as test-only
- Add comprehensive test for parse_ical_datetime function
- Move imports into function scope to reduce global imports
- Test covers DATE format, UTC datetime format, and error handling

Fixes warning: function 'parse_ical_datetime' is never used

src/event.rs

@@ -1,7 +1,7 @@
 //! Event handling and iCalendar parsing
 
-use crate::error::{CalDavError, CalDavResult};
-use chrono::{DateTime, Utc, NaiveDateTime};
+use crate::error::CalDavResult;
+use chrono::{DateTime, Utc};
 use serde::{Deserialize, Serialize};
 use std::collections::HashMap;
 use uuid::Uuid;
@@ -369,7 +369,11 @@ fn escape_ical_text(text: &str) -> String {
 }
 
 /// Parse iCalendar date/time
+#[cfg(test)]
 fn parse_ical_datetime(dt_str: &str) -> CalDavResult<DateTime<Utc>> {
+    use crate::error::CalDavError;
+    use chrono::NaiveDateTime;
+    
     // Handle different iCalendar date formats
     if dt_str.len() == 8 {
         // DATE format (YYYYMMDD)
@@ -444,4 +448,20 @@ mod tests {
         let escaped = escape_ical_text(text);
         assert_eq!(escaped, "Hello\\, world\\; this\\\\is a test");
     }
+
+    #[test]
+    fn test_parse_ical_datetime() {
+        // Test DATE format (YYYYMMDD)
+        let date_result = parse_ical_datetime("20231225").unwrap();
+        assert_eq!(date_result.format("%Y%m%d").to_string(), "20231225");
+        assert_eq!(date_result.format("%H%M%S").to_string(), "000000");
+
+        // Test UTC datetime format (YYYYMMDDTHHMMSSZ)
+        let datetime_result = parse_ical_datetime("20231225T103000Z").unwrap();
+        assert_eq!(datetime_result.format("%Y%m%dT%H%M%SZ").to_string(), "20231225T103000Z");
+
+        // Test local time format (should fail)
+        let local_result = parse_ical_datetime("20231225T103000");
+        assert!(local_result.is_err());
+    }
 }