Preserve reciprocal edges in the NetworkX dialect

grand/dialects/__init__.py

@@ -4,10 +4,8 @@
 if TYPE_CHECKING:
     from .. import Graph
 
-import pandas as pd
-
 import networkx as nx
-from networkx.classes.reportviews import NodeView
+from networkx.classes.reportviews import EdgeView, OutEdgeView
 from networkx.classes.coreviews import AdjacencyView, AtlasView
 
 
@@ -209,6 +207,11 @@ def _lookup_degree(degrees: dict, node: Hashable) -> int:
     def is_directed(self):
         return self.parent.backend.is_directed()
 
+    @property
+    def edges(self):
+        view = OutEdgeView if self.is_directed() else EdgeView
+        return view(self)
+
     def __len__(self):
         return self.parent.backend.get_node_count()
 

grand/dialects/test_dialect.py

@@ -3,13 +3,6 @@
 
 from .. import Graph
 from ..backends import NetworkXBackend
-from . import (
-    NetworkXDialect,
-    IGraphDialect,
-    NetworkitDialect,
-    _GrandAdjacencyView,
-    _GrandNodeAtlasView,
-)
 import networkx as nx
 
 
@@ -83,13 +76,16 @@ def test_out_degree(self):
     def test_nx_edges(self):
         G = Graph(directed=True).nx
         H = nx.DiGraph()
-        G.add_edge("1", "2")
+        G.add_edge("1", "2", direction="forward")
+        G.add_edge("2", "1", direction="reverse")
         G.add_edge("1", "3")
-        H.add_edge("1", "2")
+        H.add_edge("1", "2", direction="forward")
+        H.add_edge("2", "1", direction="reverse")
         H.add_edge("1", "3")
         self.assertEqual(dict(G.edges), dict(H.edges))
         self.assertEqual(dict(G.edges()), dict(H.edges()))
-        self.assertEqual(list(G.edges["1", "2"]), list(H.edges["1", "2"]))
+        self.assertEqual(G.edges["1", "2"], H.edges["1", "2"])
+        self.assertEqual(G.edges["2", "1"], H.edges["2", "1"])
 
     def test_degree_undirected(self):
         G1 = Graph(backend=NetworkXBackend(directed=False))