Ensure that the list of health statuses is exhaustive

I've finally found out how to write the macro to define the enum and
the test that matches the health statuses. Turns out I had missed one,
Inuse!!

src/main.rs

@@ -4,21 +4,33 @@ use clap::Parser;
 use libzetta::zpool::{Health, Zpool, ZpoolEngine, ZpoolOpen3};
 use prometheus::{register_int_gauge_vec, Encoder, TextEncoder};
 
-const ALL_HEALTH_STATUSES: &[Health] = {
-    // TODO: ensure that we're listing them exhaustively; there must be
-    // some macro magic I could do via a constructed closure with a match
-    // in it, but I can't figure out the syntax atm.
-    use Health::*;
-    &[
+macro_rules! define_all_health_statuses {
+    ($const_name:ident = [$($variant:tt ,)+]) => {
+       const $const_name: &[Health] = {
+           &[$(::libzetta::zpool::Health::$variant),*]
+       };
+        #[test]
+        fn test_all_statuses_exhaustive() {
+            let status = ::libzetta::zpool::Health::Online;
+            match status {
+                $(::libzetta::zpool::Health::$variant => {}),*
+            }
+        }
+   };
+}
+
+define_all_health_statuses!(
+    ALL_HEALTH_STATUSES = [
         Online,
         Degraded,
         Faulted,
         Offline,
         Available,
         Unavailable,
         Removed,
+        Inuse,
     ]
-};
+);
 
 /// Returns true if the health status is OK.
 fn is_healthy(health: &Health) -> bool {