first version. no icons, no user interaction

tests/controls/conftest.py

@@ -3,6 +3,11 @@ import pytest
 from myfasthtml.core.instances import SingleInstance
 
 
+class RootInstanceForTests(SingleInstance):
+  def __init__(self, session):
+    super().__init__(None, session, _id="TestRoot")
+
+
 @pytest.fixture(scope="session")
 def session():
   return {
@@ -20,4 +25,4 @@ def session():
 
 @pytest.fixture(scope="session")
 def root_instance(session):
-  return SingleInstance(None, session, "TestRoot")
+  return RootInstanceForTests(session=session)

tests/controls/test_treeview.py

@@ -0,0 +1,256 @@
+"""Unit tests for TreeView component."""
+import shutil
+
+import pytest
+
+from myfasthtml.controls.TreeView import TreeView, TreeNode
+from .conftest import root_instance
+
+
+@pytest.fixture(autouse=True)
+def cleanup_db():
+  shutil.rmtree(".myFastHtmlDb", ignore_errors=True)
+
+
+class TestTreeviewBehaviour:
+  """Tests for TreeView behavior and logic."""
+  
+  def test_i_can_create_tree_node_with_auto_generated_id(self):
+    """Test that TreeNode generates UUID automatically."""
+    node = TreeNode(label="Test Node", type="folder")
+    
+    assert node.id is not None
+    assert isinstance(node.id, str)
+    assert len(node.id) > 0
+  
+  def test_i_can_create_tree_node_with_default_values(self):
+    """Test that TreeNode has correct default values."""
+    node = TreeNode()
+
+    assert node.label == ""
+    assert node.type == "default"
+    assert node.parent is None
+    assert node.children == []
+
+  def test_i_can_initialize_tree_view_state(self, root_instance):
+    """Test that TreeViewState initializes with default values."""
+    tree_view = TreeView(root_instance)
+    state = tree_view._state
+
+    assert isinstance(state.items, dict)
+    assert len(state.items) == 0
+    assert state.opened == []
+    assert state.selected is None
+    assert state.editing is None
+    assert state.icon_config == {}
+
+  def test_i_can_create_empty_treeview(self, root_instance):
+    """Test creating an empty TreeView."""
+    tree_view = TreeView(root_instance)
+    
+    assert tree_view is not None
+    assert len(tree_view._state.items) == 0
+  
+  def test_i_can_add_node_to_treeview(self, root_instance):
+    """Test adding a root node to the TreeView."""
+    tree_view = TreeView(root_instance)
+    node = TreeNode(label="Root Node", type="folder")
+    
+    tree_view.add_node(node)
+    
+    assert node.id in tree_view._state.items
+    assert tree_view._state.items[node.id].label == "Root Node"
+    assert tree_view._state.items[node.id].parent is None
+  
+  def test_i_can_add_child_node(self, root_instance):
+    """Test adding a child node to a parent."""
+    tree_view = TreeView(root_instance)
+    parent = TreeNode(label="Parent", type="folder")
+    child = TreeNode(label="Child", type="file")
+    
+    tree_view.add_node(parent)
+    tree_view.add_node(child, parent_id=parent.id)
+    
+    assert child.id in tree_view._state.items
+    assert child.id in parent.children
+    assert child.parent == parent.id
+  
+  def test_i_can_set_icon_config(self, root_instance):
+    """Test setting icon configuration."""
+    tree_view = TreeView(root_instance)
+    config = {
+        "folder": "fluent.folder",
+        "file": "fluent.document"
+    }
+    
+    tree_view.set_icon_config(config)
+    
+    assert tree_view._state.icon_config == config
+    assert tree_view._state.icon_config["folder"] == "fluent.folder"
+  
+  def test_i_can_toggle_node(self, root_instance):
+    """Test expand/collapse a node."""
+    tree_view = TreeView(root_instance)
+    node = TreeNode(label="Node", type="folder")
+    tree_view.add_node(node)
+    
+    # Initially closed
+    assert node.id not in tree_view._state.opened
+    
+    # Toggle to open
+    tree_view._toggle_node(node.id)
+    assert node.id in tree_view._state.opened
+    
+    # Toggle to close
+    tree_view._toggle_node(node.id)
+    assert node.id not in tree_view._state.opened
+  
+  def test_i_can_expand_all_nodes(self, root_instance):
+    """Test that expand_all opens all nodes with children."""
+    tree_view = TreeView(root_instance)
+    
+    # Create hierarchy: root -> child1 -> grandchild
+    #                        -> child2 (leaf)
+    root = TreeNode(label="Root", type="folder")
+    child1 = TreeNode(label="Child 1", type="folder")
+    grandchild = TreeNode(label="Grandchild", type="file")
+    child2 = TreeNode(label="Child 2", type="file")
+    
+    tree_view.add_node(root)
+    tree_view.add_node(child1, parent_id=root.id)
+    tree_view.add_node(grandchild, parent_id=child1.id)
+    tree_view.add_node(child2, parent_id=root.id)
+    
+    # Initially all closed
+    assert len(tree_view._state.opened) == 0
+    
+    # Expand all
+    tree_view.expand_all()
+    
+    # Nodes with children should be opened
+    assert root.id in tree_view._state.opened
+    assert child1.id in tree_view._state.opened
+    
+    # Leaf nodes should not be in opened list
+    assert grandchild.id not in tree_view._state.opened
+    assert child2.id not in tree_view._state.opened
+  
+  def test_i_can_select_node(self, root_instance):
+    """Test selecting a node."""
+    tree_view = TreeView(root_instance)
+    node = TreeNode(label="Node", type="folder")
+    tree_view.add_node(node)
+    
+    tree_view._select_node(node.id)
+    
+    assert tree_view._state.selected == node.id
+  
+  def test_i_can_start_rename_node(self, root_instance):
+    """Test starting rename mode for a node."""
+    tree_view = TreeView(root_instance)
+    node = TreeNode(label="Old Name", type="folder")
+    tree_view.add_node(node)
+    
+    tree_view._start_rename(node.id)
+    
+    assert tree_view._state.editing == node.id
+  
+  def test_i_can_save_rename_node(self, root_instance):
+    """Test saving renamed node with new label."""
+    tree_view = TreeView(root_instance)
+    node = TreeNode(label="Old Name", type="folder")
+    tree_view.add_node(node)
+    tree_view._start_rename(node.id)
+    
+    tree_view._save_rename(node.id, "New Name")
+    
+    assert tree_view._state.items[node.id].label == "New Name"
+    assert tree_view._state.editing is None
+  
+  def test_i_can_cancel_rename_node(self, root_instance):
+    """Test canceling rename operation."""
+    tree_view = TreeView(root_instance)
+    node = TreeNode(label="Name", type="folder")
+    tree_view.add_node(node)
+    tree_view._start_rename(node.id)
+    
+    tree_view._cancel_rename()
+    
+    assert tree_view._state.editing is None
+    assert tree_view._state.items[node.id].label == "Name"
+  
+  def test_i_can_delete_leaf_node(self, root_instance):
+    """Test deleting a node without children."""
+    tree_view = TreeView(root_instance)
+    parent = TreeNode(label="Parent", type="folder")
+    child = TreeNode(label="Child", type="file")
+    
+    tree_view.add_node(parent)
+    tree_view.add_node(child, parent_id=parent.id)
+    
+    # Delete child (leaf node)
+    tree_view._delete_node(child.id)
+    
+    assert child.id not in tree_view._state.items
+    assert child.id not in parent.children
+  
+  def test_i_can_add_sibling_node(self, root_instance):
+    """Test adding a sibling node."""
+    tree_view = TreeView(root_instance)
+    parent = TreeNode(label="Parent", type="folder")
+    child1 = TreeNode(label="Child 1", type="file")
+    
+    tree_view.add_node(parent)
+    tree_view.add_node(child1, parent_id=parent.id)
+    
+    # Add sibling to child1
+    tree_view._add_sibling(child1.id, new_label="Child 2")
+    
+    assert len(parent.children) == 2
+    # Sibling should be after child1
+    assert parent.children.index(child1.id) < len(parent.children) - 1
+  
+  def test_i_cannot_delete_node_with_children(self, root_instance):
+    """Test that deleting a node with children raises an error."""
+    tree_view = TreeView(root_instance)
+    parent = TreeNode(label="Parent", type="folder")
+    child = TreeNode(label="Child", type="file")
+    
+    tree_view.add_node(parent)
+    tree_view.add_node(child, parent_id=parent.id)
+    
+    # Try to delete parent (has children)
+    with pytest.raises(ValueError, match="Cannot delete node.*with children"):
+      tree_view._delete_node(parent.id)
+  
+  def test_i_cannot_add_sibling_to_root(self, root_instance):
+    """Test that adding sibling to root node raises an error."""
+    tree_view = TreeView(root_instance)
+    root = TreeNode(label="Root", type="folder")
+    tree_view.add_node(root)
+    
+    # Try to add sibling to root (no parent)
+    with pytest.raises(ValueError, match="Cannot add sibling to root node"):
+      tree_view._add_sibling(root.id)
+  
+  def test_i_cannot_select_nonexistent_node(self, root_instance):
+    """Test that selecting a nonexistent node raises an error."""
+    tree_view = TreeView(root_instance)
+    
+    # Try to select node that doesn't exist
+    with pytest.raises(ValueError, match="Node.*does not exist"):
+      tree_view._select_node("nonexistent_id")
+
+
+class TestTreeViewRender:
+  """Tests for TreeView HTML rendering."""
+  
+  def test_treeview_renders_correctly(self):
+    """Test that TreeView generates correct HTML structure."""
+    # Signature only - implementation later
+    pass
+  
+  def test_node_action_buttons_are_rendered(self):
+    """Test that action buttons are present in rendered HTML."""
+    # Signature only - implementation later
+    pass