test: Add a test for #1257 (#1260)

We take the opportunity to change the `ignore` in `hugr_validation_0` to
`should_panic`

hugr-core/src/builder/tail_loop.rs

@@ -194,4 +194,15 @@ mod test {
 
         Ok(())
     }
+
+    #[test]
+    #[should_panic] // issue 1257: When building a TailLoop, calling outputs_arr, you are given an OrderEdge "output wire"
+    fn tailloop_output_arr() {
+        let mut builder =
+            TailLoopBuilder::new(type_row![], type_row![], type_row![], ExtensionSet::new())
+                .unwrap();
+        let control = builder.add_load_value(Value::false_val());
+        let tailloop = builder.finish_with_outputs(control, []).unwrap();
+        let [] = tailloop.outputs_arr();
+    }
 }

hugr-core/src/hugr.rs

@@ -328,7 +328,7 @@ mod test {
 
     #[test]
     #[cfg_attr(miri, ignore)] // Opening files is not supported in (isolated) miri
-    #[ignore = "issue 1225: In serialization we do not distinguish between unknown CustomConst serialized value invalid but known CustomConst serialized values"]
+    #[should_panic] // issue 1225: In serialization we do not distinguish between unknown CustomConst serialized value invalid but known CustomConst serialized values"
     fn hugr_validation_0() {
         // https://github.com/CQCL/hugr/issues/1091 bad case
         let mut hugr: Hugr = serde_json::from_reader(BufReader::new(