test: prove provider panic containment and isolation

crates/server/src/service.rs

@@ -319,4 +319,37 @@ mod tests {
         assert_eq!(results["a.se"], ProviderResult::NoData);
         assert!(matches!(results["b.se"], ProviderResult::Ok { .. }));
     }
+
+    /// Provider whose parse() panics — must be contained by spawn_blocking.
+    struct PanickingProvider;
+
+    impl ProviderHandle for PanickingProvider {
+        fn name(&self) -> &str {
+            "panic.se"
+        }
+
+        fn requests(&self, number: &str) -> Result<Vec<String>, HostError> {
+            Ok(vec![format!("https://example.test/{number}")])
+        }
+
+        fn parse(&self, _number: &str, _responses: &[FetchedResponse]) -> ParseOutcome {
+            panic!("provider blew up");
+        }
+    }
+
+    #[tokio::test]
+    async fn provider_panic_is_contained_and_isolated() {
+        let panicking = Arc::new(PanickingProvider);
+        let healthy = Arc::new(FakeProvider {
+            name: "ok.se",
+            outcome: || ParseOutcome::Ok(entry()),
+        });
+        let fetcher = Arc::new(FakeFetcher::new(false));
+        let svc = service(vec![panicking, healthy], fetcher);
+
+        let results = svc.lookup("0700000000").await;
+
+        assert_eq!(results["panic.se"], ProviderResult::ParseFailed);
+        assert!(matches!(results["ok.se"], ProviderResult::Ok { .. }));
+    }
 }