add leaf_into tests

Author: orxfun

tests/leaf_nodes.rs

@@ -2,35 +2,69 @@
 
 use orx_tree::*;
 
+/// https://github.com/orxfun/orx-tree/issues/183
 #[test]
-fn root_into_new_tree() {
+fn leaf_into_new_tree() {
     let mut tree = DynTree::new(0);
+    let idx = tree.root_mut().push_child(1);
 
-    let tree2: DynTree<_> = tree.root_mut().into_new_tree();
+    let tree2: DynTree<_> = tree.node_mut(idx).into_new_tree();
 
     assert_eq!(tree2.len(), 1);
     assert_eq!(
         tree2.root().walk::<Dfs>().copied().collect::<Vec<_>>(),
-        vec![0]
+        vec![1]
     );
 }
 
-/// https://github.com/orxfun/orx-tree/issues/183
 #[test]
-fn leaf_into_new_tree() {
+fn root_into_new_tree() {
     let mut tree = DynTree::new(0);
-    tree.root_mut().push_child(1);
 
-    let tree2: DynTree<_> = tree
-        .root_mut()
-        .children_mut()
-        .nth(0)
-        .unwrap()
-        .into_new_tree();
+    let tree2: DynTree<_> = tree.root_mut().into_new_tree();
 
     assert_eq!(tree2.len(), 1);
     assert_eq!(
         tree2.root().walk::<Dfs>().copied().collect::<Vec<_>>(),
-        vec![1]
+        vec![0]
     );
 }
+
+#[test]
+fn leaf_into_walk() {
+    let mut tree = DynTree::new(0);
+    let idx = tree.root_mut().push_child(1);
+
+    let values: Vec<_> = tree.node_mut(idx).into_walk::<Dfs>().collect();
+    assert_eq!(values, vec![1]);
+
+    let remaining: Vec<_> = tree.root().walk::<Dfs>().copied().collect();
+    assert_eq!(remaining, vec![0]);
+}
+
+#[test]
+fn leaf_into_leaves() {
+    let mut tree = DynTree::new(0);
+    let idx = tree.root_mut().push_child(1);
+
+    let values: Vec<_> = tree.node_mut(idx).into_leaves::<Dfs>().collect();
+    assert_eq!(values, vec![1]);
+
+    let remaining: Vec<_> = tree.root().walk::<Dfs>().copied().collect();
+    assert_eq!(remaining, vec![0]);
+}
+
+#[test]
+fn leaf_into_subtree() {
+    let mut tree = DynTree::new(0);
+    let idx = tree.root_mut().push_child(1);
+
+    let subtree = tree.node_mut(idx).into_subtree();
+    let mut tree2 = DynTree::new(42);
+    tree2.root_mut().push_child_tree(subtree);
+    let values: Vec<_> = tree2.root().walk::<Dfs>().copied().collect();
+    assert_eq!(values, vec![42, 1]);
+
+    let remaining: Vec<_> = tree.root().walk::<Dfs>().copied().collect();
+    assert_eq!(remaining, vec![0]);
+}