Consistent sep for subtree

CHANGELOG.md

@@ -6,7 +6,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 ### Added:
-- Misc: Pull request template
+- Misc: Pull request template.
+### Fixed:
+- Tree Helper: Subtree to inherit `sep` property from root node.
 
 ## [0.21.1] - 2024-08-29
 ### Changed:

bigtree/tree/helper.py

@@ -92,6 +92,7 @@ def get_subtree(
     Returns:
         (Node)
     """
+    tree_sep = tree.sep
     tree = tree.copy()
 
     if node_name_or_path:
@@ -104,6 +105,9 @@ def get_subtree(
 
     if max_depth:
         tree = prune_tree(tree, max_depth=max_depth)
+
+    # Assign original tree's sep to subtree
+    tree.sep = tree_sep
     return tree
 
 

tests/tree/test_helper.py

@@ -47,6 +47,25 @@ class NodeA(node.Node):
         assert_tree_structure_basenode_root_attr(root_clone)
 
 
+class TestGetSubtree:
+    @staticmethod
+    def test_get_subtree(tree_node):
+        # Subtree is b/d, b/e/g, b/e/h
+        tree_subtree = helper.get_subtree(tree_node, "a/b")
+        assert tree_subtree.node_name == "b"
+        assert len(tree_subtree.children) == 2
+        assert not len(tree_subtree.children[0].children)
+        assert len(tree_subtree.children[1].children) == 2
+
+    @staticmethod
+    def test_get_subtree_sep(tree_node):
+        # Subtree is b/d, b/e/g, b/e/h
+        tree_node.sep = "."
+        tree_subtree = helper.get_subtree(tree_node, "a.b")
+        assert tree_subtree.children[0].path_name == ".b.d"
+        assert tree_subtree.children[1].path_name == ".b.e"
+
+
 class TestPruneTree:
     @staticmethod
     def test_prune_tree(tree_node):