test: add unit test for unix time

Signed-off-by: Zhenchi <[email protected]>

src/lib.rs

@@ -121,6 +121,15 @@ mod tests {
         let _ = nanos_per_cycle();
     }
 
+    #[test]
+    #[wasm_bindgen_test]
+    fn test_unix_time() {
+        let now = Instant::now();
+        let anchor = Anchor::new();
+        let unix_nanos = now.as_unix_nanos(&anchor);
+        assert!(unix_nanos > 0);
+    }
+
     #[test]
     fn test_duration() {
         let mut rng = rand::thread_rng();