Add tests for AssetRef::make_partial_parent

Author: alexdewar

src/asset.rs

@@ -1464,6 +1464,64 @@ mod tests {
         assert_eq!(count, 1);
     }
 
+    #[fixture]
+    fn parent_asset(asset_divisible: Asset) -> AssetRef {
+        let asset = AssetRef::from(asset_divisible);
+        let mut parent = None;
+
+        asset.into_for_each_child(&mut 0, |maybe_parent, _| {
+            if parent.is_none() {
+                parent = maybe_parent.cloned();
+            }
+        });
+
+        parent.expect("Divisible asset should create a parent")
+    }
+
+    #[rstest]
+    #[case::subset_of_children(2, false)]
+    #[case::all_children(3, true)]
+    fn make_partial_parent(
+        parent_asset: AssetRef,
+        #[case] num_units: u32,
+        #[case] expect_same_asset: bool,
+    ) {
+        let parent = parent_asset;
+        assert!(parent.is_parent());
+
+        let partial_parent = parent.make_partial_parent(num_units);
+
+        assert!(partial_parent.is_parent());
+        assert_eq!(
+            partial_parent.capacity(),
+            AssetCapacity::Discrete(num_units, Capacity(4.0))
+        );
+        assert_eq!(partial_parent.num_children(), Some(num_units));
+        assert_eq!(partial_parent.group_id(), parent.group_id());
+        assert_eq!(partial_parent.agent_id(), parent.agent_id());
+        assert_eq!(Rc::ptr_eq(&partial_parent.0, &parent.0), expect_same_asset);
+        assert_eq!(parent.capacity(), AssetCapacity::Discrete(3, Capacity(4.0)));
+    }
+
+    #[rstest]
+    #[should_panic(expected = "Cannot make a partial parent from a non-parent asset")]
+    fn make_partial_parent_panics_for_non_parent_asset(asset_divisible: Asset) {
+        let asset = AssetRef::from(asset_divisible);
+        asset.make_partial_parent(1);
+    }
+
+    #[rstest]
+    #[should_panic(expected = "Cannot make a partial parent with zero units")]
+    fn make_partial_parent_panics_for_zero_units(parent_asset: AssetRef) {
+        parent_asset.make_partial_parent(0);
+    }
+
+    #[rstest]
+    #[should_panic(expected = "Cannot make a partial parent with more units than original")]
+    fn make_partial_parent_panics_for_too_many_units(parent_asset: AssetRef) {
+        parent_asset.make_partial_parent(4);
+    }
+
     #[rstest]
     fn asset_commission(process: Process) {
         // Test successful commissioning of Future asset