From 857130acb010befd6b47e432a8225a7f98219672 Mon Sep 17 00:00:00 2001
From: Mark Bonicillo <mark.bonicillo@pnnl.gov>
Date: Mon, 15 Apr 2024 14:53:08 -0700
Subject: [PATCH] Fix bugs in _add_item; add tests for add_edge

---
 hypernetx/classes/hypergraph.py            | 13 ++++--
 hypernetx/classes/tests/test_hypergraph.py | 54 ++++++++++++++++------
 2 files changed, 48 insertions(+), 19 deletions(-)

diff --git a/hypernetx/classes/hypergraph.py b/hypernetx/classes/hypergraph.py
index 4d931b3d..5555a328 100644
--- a/hypernetx/classes/hypergraph.py
+++ b/hypernetx/classes/hypergraph.py
@@ -2,6 +2,7 @@
 # All rights reserved.
 from __future__ import annotations
 
+import random
 import warnings
 
 warnings.filterwarnings("default", category=DeprecationWarning)
@@ -1216,7 +1217,7 @@ def add_incidences_from(self, incidences, inplace=True):
 
     def _add_item(self, uid, level=2, data=None, inplace=True):
         data = data or {}
-        self._add_items_from([(uid, data)], level=level, inplace=inplace)
+        return self._add_items_from([(uid, data)], level=level, inplace=inplace)
 
     def _add_items_from(self, items, level=2, inplace=True):
         """Items must be a list of uids and/or tuples
@@ -1243,10 +1244,12 @@ def _add_items_from(self, items, level=2, inplace=True):
                 df.properties, edge_ps=ep, node_ps=np, name=self.name
             )
             return self
-        else:
-            return self._construct_hyp_from_stores(
-                df.properties, edge_ps=ep, node_ps=np, name=name
-            )
+        return self._construct_hyp_from_stores(
+            df.properties,
+            edge_ps=ep,
+            node_ps=np,
+            name=f"{self.name}-{random.randint(1, 100)}",
+        )
 
     #### This should follow behavior of restrictions
     def remove_edges(self, keys, name=None, inplace=True):
diff --git a/hypernetx/classes/tests/test_hypergraph.py b/hypernetx/classes/tests/test_hypergraph.py
index 12425953..851d660f 100644
--- a/hypernetx/classes/tests/test_hypergraph.py
+++ b/hypernetx/classes/tests/test_hypergraph.py
@@ -69,20 +69,46 @@ def test_hypergraph_from_bipartite(sbsd_hypergraph):
     assert len(HB.nodes) == 8
 
 
-@pytest.mark.skip("Deprecated method; will support in later release")
-def test_add_node_to_edge(sbs):
-    H = Hypergraph(sbs.edgedict)
-    assert H.shape == (7, 6)
-    node = "B"
-    edge = "P"
-    H.add_node_to_edge(node, edge)
-    assert H.shape == (8, 6)
-    # add edge with nodes already in hypergraph
-    H.add_edge({"Z": ["A", "B"]})
-    assert H.shape == (8, 7)
-    # add edge not in hypergraph with nodes not in hypergraph
-    H.add_edge({"Y": ["M", "N"]})
-    assert H.shape == (10, 8)
+def test_add_edge_inplace(sbs):
+    h = Hypergraph(sbs.edgedict)
+    assert h.shape == (7, 6)
+
+    # add a new edge in place; i.e. the current hypergraph should be mutated
+    new_edge = "X"
+    h.add_edge(new_edge)
+
+    # the Hypergraph should not increase its number of edges and incidences because the current behavior of adding
+    # an edge does not connect two or more nodes.
+    # In other words, adding an edge with no nodes
+    assert h.shape == (7, 6)
+    assert new_edge not in h.edges.elements
+
+    # the new edge has no user-defined property data, so it should not be listed in the PropertyStore
+    assert new_edge not in h.edges.properties
+
+    # However, the new_edge will be listed in the complete list of all user and non-user-define properties for all edges
+    assert new_edge in h.edges.to_dataframe.index.tolist()
+
+    assert new_edge in h.edges.to_dataframe.index.tolist()
+
+
+def test_add_edge_not_inplace(sbs):
+    h = Hypergraph(sbs.edgedict)
+    assert h.shape == (7, 6)
+
+    # add a new edge not in place; the current hypergraph should be diffrent from the new hypergraph
+    # created from add_edge
+    new_edge = "X"
+    new_hg = h.add_edge(new_edge, inplace=False)
+
+    assert new_hg.shape == (7, 6)
+    assert new_edge not in new_hg.edges.elements
+
+    assert new_edge not in new_hg.edges.properties
+    assert new_edge in new_hg.edges.to_dataframe.index.tolist()
+
+    # verify that the new edge is not in the old HyperGraph
+    assert new_edge not in h.edges.to_dataframe.index.tolist()
 
 
 def test_remove_edges(sbs):