Add test for the size of chrono's main data types

Author: pitdicker

src/lib.rs

@@ -627,3 +627,27 @@ macro_rules! expect {
         }
     };
 }
+
+#[cfg(test)]
+mod tests {
+    #[cfg(feature = "clock")]
+    use crate::{DateTime, FixedOffset, Local, NaiveDate, NaiveDateTime, NaiveTime, Utc};
+
+    #[test]
+    #[allow(deprecated)]
+    #[cfg(feature = "clock")]
+    fn test_type_sizes() {
+        use core::mem::size_of;
+        assert_eq!(size_of::<NaiveDate>(), 4);
+        assert_eq!(size_of::<Option<NaiveDate>>(), 8);
+        assert_eq!(size_of::<NaiveTime>(), 8);
+        assert_eq!(size_of::<Option<NaiveTime>>(), 12);
+        assert_eq!(size_of::<NaiveDateTime>(), 12);
+        assert_eq!(size_of::<Option<NaiveDateTime>>(), 16);
+
+        assert_eq!(size_of::<DateTime<Utc>>(), 12);
+        assert_eq!(size_of::<DateTime<FixedOffset>>(), 16);
+        assert_eq!(size_of::<DateTime<Local>>(), 16);
+        assert_eq!(size_of::<Option<DateTime<FixedOffset>>>(), 20);
+    }
+}