Refactored instances management

tests/core/test_network_utils.py

@@ -311,7 +311,7 @@ class TestFromParentChildList:
     nodes, edges = from_parent_child_list(items)
     
     assert len(nodes) == 1
-    assert nodes[0] == {"id": "root", "label": "Root"}
+    assert nodes[0] == {'color': '#ff9999', 'id': 'root', 'label': 'Root'}
     assert len(edges) == 0
   
   def test_i_can_convert_simple_parent_child_relationship(self):
@@ -323,7 +323,7 @@ class TestFromParentChildList:
     nodes, edges = from_parent_child_list(items)
     
     assert len(nodes) == 2
-    assert {"id": "root", "label": "Root"} in nodes
+    assert {'color': '#ff9999', 'id': 'root', 'label': 'Root'} in nodes
     assert {"id": "child", "label": "Child"} in nodes
     
     assert len(edges) == 1
@@ -513,3 +513,136 @@ class TestFromParentChildList:
     
     ghost_node = [n for n in nodes if n["id"] == "ghost_parent"][0]
     assert ghost_node["label"] == "ghost_parent"
+  
+  def test_i_can_apply_root_color_to_single_root(self):
+    """Test that a single root node receives the root_color."""
+    items = [{"id": "root", "label": "Root"}]
+    nodes, edges = from_parent_child_list(items, root_color="#ff0000")
+    
+    assert len(nodes) == 1
+    assert nodes[0]["color"] == "#ff0000"
+  
+  def test_i_can_apply_root_color_to_multiple_roots(self):
+    """Test root_color is assigned to all nodes without parent."""
+    items = [
+        {"id": "root1", "label": "Root 1"},
+        {"id": "root2", "label": "Root 2"},
+        {"id": "child", "parent": "root1", "label": "Child"}
+    ]
+    nodes, edges = from_parent_child_list(items, root_color="#aa0000")
+    
+    root_nodes = [n for n in nodes if n["id"] in ("root1", "root2")]
+    assert all(n.get("color") == "#aa0000" for n in root_nodes)
+    
+    # child must NOT have root_color
+    child_node = next(n for n in nodes if n["id"] == "child")
+    assert "color" not in child_node
+  
+  def test_i_can_handle_root_with_parent_none(self):
+    """Test that root_color is applied when parent=None."""
+    items = [
+        {"id": "r1", "parent": None, "label": "R1"}
+    ]
+    nodes, edges = from_parent_child_list(items, root_color="#112233")
+    
+    assert nodes[0]["color"] == "#112233"
+  
+  def test_i_can_handle_root_with_parent_empty_string(self):
+    """Test that root_color is applied when parent=''."""
+    items = [
+        {"id": "r1", "parent": "", "label": "R1"}
+    ]
+    nodes, edges = from_parent_child_list(items, root_color="#334455")
+    
+    assert nodes[0]["color"] == "#334455"
+  
+  def test_i_do_not_apply_root_color_to_non_roots(self):
+    """Test that only real roots receive root_color."""
+    items = [
+        {"id": "root", "label": "Root"},
+        {"id": "child", "parent": "root", "label": "Child"}
+    ]
+    nodes, edges = from_parent_child_list(items, root_color="#ff0000")
+    
+    # Only one root → only this one has the color
+    root_node = next(n for n in nodes if n["id"] == "root")
+    assert root_node["color"] == "#ff0000"
+    
+    child_node = next(n for n in nodes if n["id"] == "child")
+    assert "color" not in child_node
+  
+  def test_i_do_not_override_ghost_color_with_root_color(self):
+    """Ghost nodes must keep ghost_color, not root_color."""
+    items = [
+        {"id": "child", "parent": "ghost_parent", "label": "Child"}
+    ]
+    nodes, edges = from_parent_child_list(
+      items,
+      root_color="#ff0000",
+      ghost_color="#00ff00"
+    )
+    
+    ghost_node = next(n for n in nodes if n["id"] == "ghost_parent")
+    assert ghost_node["color"] == "#00ff00"
+    
+    # child is not root → no color
+    child_node = next(n for n in nodes if n["id"] == "child")
+    assert "color" not in child_node
+  
+  def test_i_can_use_custom_root_color(self):
+    """Test that a custom root_color is applied instead of default."""
+    items = [{"id": "root", "label": "Root"}]
+    nodes, edges = from_parent_child_list(items, root_color="#123456")
+    
+    assert nodes[0]["color"] == "#123456"
+  
+  def test_i_can_mix_root_nodes_and_ghost_nodes(self):
+    """Ensure root_color applies only to roots and ghost nodes keep ghost_color."""
+    items = [
+        {"id": "root", "label": "Root"},
+        {"id": "child", "parent": "ghost_parent", "label": "Child"}
+    ]
+    nodes, edges = from_parent_child_list(
+      items,
+      root_color="#ff0000",
+      ghost_color="#00ff00"
+    )
+    
+    root_node = next(n for n in nodes if n["id"] == "root")
+    ghost_node = next(n for n in nodes if n["id"] == "ghost_parent")
+    
+    assert root_node["color"] == "#ff0000"
+    assert ghost_node["color"] == "#00ff00"
+  
+  def test_i_do_not_mark_node_as_root_if_parent_field_exists(self):
+    """Node with parent key but non-empty value should NOT get root_color."""
+    items = [
+        {"id": "root", "label": "Root"},
+        {"id": "child", "parent": "root", "label": "Child"},
+        {"id": "other", "parent": "unknown_parent", "label": "Other"}
+    ]
+    nodes, edges = from_parent_child_list(
+      items,
+      root_color="#ff0000",
+      ghost_color="#00ff00"
+    )
+    
+    # "root" is the only real root
+    root_node = next(n for n in nodes if n["id"] == "root")
+    assert root_node["color"] == "#ff0000"
+    
+    # "other" is NOT root, even though its parent is missing
+    other_node = next(n for n in nodes if n["id"] == "other")
+    assert "color" not in other_node
+    
+    # ghost parent must have ghost_color
+    ghost_node = next(n for n in nodes if n["id"] == "unknown_parent")
+    assert ghost_node["color"] == "#00ff00"
+  
+  def test_i_do_no_add_root_color_when_its_none(self):
+    """Test that a single root node receives the root_color."""
+    items = [{"id": "root", "label": "Root"}]
+    nodes, edges = from_parent_child_list(items, root_color=None)
+    
+    assert len(nodes) == 1
+    assert "color" not in nodes[0]