[tests] Add API test suite

tests-api/mocks/custom_node_manager.py

@@ -0,0 +1,26 @@
+"""
+Mock CustomNodeManager for testing purposes
+"""
+
+class CustomNodeManager:
+    """
+    Mock implementation of the CustomNodeManager class
+    """
+    instance = None
+    
+    def __init__(self):
+        self.custom_nodes = {}
+        self.node_paths = []
+        self.refresh_timeout = None
+        
+    def get_node_path(self, node_class):
+        """
+        Mock implementation to get the path for a node class
+        """
+        return self.custom_nodes.get(node_class, None)
+        
+    def update_node_paths(self):
+        """
+        Mock implementation to update node paths
+        """
+        pass