fix mirage test entries_expire for macos

Author: ansiwen

test/mirage/tests.ml

@@ -358,9 +358,10 @@ let entries_expire () =
   (* Wait for cache entry to expire *)
   (* Entry becomes Stale after refresh (40 ticks * 2ms = 80ms) *)
   (* Stale entry is removed after timeout (800 ticks * 2ms = 1600ms) from initial creation *)
-  Mirage_sleep.ns (Duration.of_sec 5) >>= fun () ->
+  let delay = if os_linux_bsd () then 5 else 20 in
+  Mirage_sleep.ns (Duration.of_sec delay) >>= fun () ->
   (* Querying now should generate an ARP request since entry should be removed *)
-  timeout ~time:2000 (not_in_cache ~listen:speak.netif expected_arp_query listen.arp first_ip)
+  timeout ~time:1000 (not_in_cache ~listen:speak.netif expected_arp_query listen.arp first_ip)
 
 (* RFC isn't strict on how many times to try, so we'll just say any number
    greater than 1 is fine *)