Implement Arbitrary for timezones

src/offset/fixed.rs

@@ -152,6 +152,16 @@ impl fmt::Display for FixedOffset {
     }
 }
 
+#[cfg(feature = "arbitrary")]
+impl arbitrary::Arbitrary<'_> for FixedOffset {
+    fn arbitrary(u: &mut arbitrary::Unstructured) -> arbitrary::Result<FixedOffset> {
+        let secs = u.int_in_range(-86_399..=86_399)?;
+        let fixed_offset = FixedOffset::east_opt(secs)
+            .expect("Could not generate a valid chrono::FixedOffset. It looks like implementation of Arbitrary for FixedOffset is erroneous.");
+        Ok(fixed_offset)
+    }
+}
+
 // addition or subtraction of FixedOffset to/from Timelike values is the same as
 // adding or subtracting the offset's local_minus_utc value
 // but keep keeps the leap second information.

src/offset/local/mod.rs

@@ -52,6 +52,7 @@ mod tz_info;
 /// ```
 #[derive(Copy, Clone, Debug)]
 #[cfg_attr(feature = "rkyv", derive(Archive, Deserialize, Serialize))]
+#[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 pub struct Local;
 
 impl Local {

src/offset/utc.rs

@@ -41,6 +41,7 @@ use crate::{Date, DateTime};
 /// ```
 #[derive(Copy, Clone, PartialEq, Eq)]
 #[cfg_attr(feature = "rkyv", derive(Archive, Deserialize, Serialize))]
+#[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 pub struct Utc;
 
 #[cfg(feature = "clock")]