data: add insert_sibling function to DNode

This patch introduce the insert_sibling function usable for inserting
data nodes on the module level.

Add a unit test. A presence container is added on the conf container of
the yolo-nodetypes module to avoid this error:
> libyang.util.LibyangError: failed to parse data tree: Too few "list1" instances.

Fixes: #95
Signed-off-by: Stefan Gula <steweg@gmail.com>
Signed-off-by: Samuel Gauthier <samuel.gauthier@6wind.com>

Author: steweg

cffi/cdefs.h

@@ -971,6 +971,7 @@ LY_ERR lyd_any_value_str(const struct lyd_node *, char **);
 LY_ERR lyd_merge_tree(struct lyd_node **, const struct lyd_node *, uint16_t);
 LY_ERR lyd_merge_siblings(struct lyd_node **, const struct lyd_node *, uint16_t);
 LY_ERR lyd_insert_child(struct lyd_node *, struct lyd_node *);
+LY_ERR lyd_insert_sibling(struct lyd_node *, struct lyd_node *, struct lyd_node **);
 LY_ERR lyd_diff_apply_all(struct lyd_node **, const struct lyd_node *);
 
 #define LYD_DUP_NO_META  ...

libyang/data.py

@@ -322,6 +322,11 @@ def insert_child(self, node):
         if ret != lib.LY_SUCCESS:
             raise self.context.error("cannot insert node")
 
+    def insert_sibling(self, node):
+        ret = lib.lyd_insert_sibling(self.cdata, node.cdata, ffi.NULL)
+        if ret != lib.LY_SUCCESS:
+            raise self.context.error("cannot insert sibling")
+
     def name(self) -> str:
         return c2str(self.cdata.schema.name)
 

tests/test_data.py

@@ -20,6 +20,7 @@
     IOType,
     LibyangError,
 )
+from libyang.data import dict_to_dnode
 
 
 YANG_DIR = os.path.join(os.path.dirname(__file__), "yang")
@@ -32,6 +33,7 @@ def setUp(self):
         modules = [
             self.ctx.load_module("ietf-netconf"),
             self.ctx.load_module("yolo-system"),
+            self.ctx.load_module("yolo-nodetypes"),
         ]
 
         for mod in modules:
@@ -922,3 +924,18 @@ def test_dnode_unlink(self):
             self.assertIsNone(child, None)
         finally:
             dnode.free()
+
+    def test_dnode_insert_sibling(self):
+        MAIN = {"yolo-nodetypes:conf": {"percentage": "20.2"}}
+        SIBLING = {"yolo-nodetypes:test1": 10}
+        module = self.ctx.get_module("yolo-nodetypes")
+        dnode1 = dict_to_dnode(MAIN, module, None, validate=False)
+        dnode2 = dict_to_dnode(SIBLING, module, None, validate=False)
+        self.assertEqual(len(list(dnode1.siblings(include_self=False))), 0)
+        self.assertEqual(len(list(dnode2.siblings(include_self=False))), 0)
+        dnode2.insert_sibling(dnode1)
+        self.assertEqual(len(list(dnode1.siblings(include_self=False))), 1)
+        self.assertEqual(len(list(dnode2.siblings(include_self=False))), 1)
+        sibling = next(dnode1.siblings(include_self=False), None)
+        self.assertIsInstance(sibling, DLeaf)
+        self.assertEqual(sibling.cdata, dnode2.cdata)

tests/yang/yolo/yolo-nodetypes.yang

@@ -12,6 +12,7 @@ module yolo-nodetypes {
   }
 
   container conf {
+    presence "enable conf";
     description
       "Configuration.";
     leaf percentage {
@@ -62,4 +63,8 @@ module yolo-nodetypes {
       type string;
     }
   }
+
+  leaf test1 {
+    type uint8;
+  }
 }