Add more comprehensive tests for pydot (#5792)

* Add more comprehensive tests for pydot

* remove the second element from frozenset for cleaner tests

Co-authored-by: Ross Barnowski <rossbar@berkeley.edu>

2 files changed, 29 insertions, 5 deletions

diff --git a/networkx/drawing/nx_pydot.py b/networkx/drawing/nx_pydot.py
index 45115989..2b01f59f 100644
--- a/networkx/drawing/nx_pydot.py
+++ b/networkx/drawing/nx_pydot.py
@@ -277,8 +277,8 @@ def to_pydot(N):
                 or _check_colon_quotes(v)
                 or (
                     any(
-                        (_check_colon_quotes(k) or _check_colon_quotes(v))
-                        for k, v in edgedata.items()
+                        (_check_colon_quotes(k) or _check_colon_quotes(val))
+                        for k, val in str_edgedata.items()
                     )
                 )
             )
@@ -293,15 +293,15 @@ def to_pydot(N):
 
     else:
         for u, v, edgedata in N.edges(data=True):
-            str_edgedata = {k: str(v) for k, v in edgedata.items()}
+            str_edgedata = {str(k): str(v) for k, v in edgedata.items()}
             u, v = str(u), str(v)
             raise_error = (
                 _check_colon_quotes(u)
                 or _check_colon_quotes(v)
                 or (
                     any(
-                        (_check_colon_quotes(k) or _check_colon_quotes(v))
-                        for k, v in edgedata.items()
+                        (_check_colon_quotes(k) or _check_colon_quotes(val))
+                        for k, val in str_edgedata.items()
                     )
                 )
             )
diff --git a/networkx/drawing/tests/test_pydot.py b/networkx/drawing/tests/test_pydot.py
index 134e0112..2e5e3ec6 100644
--- a/networkx/drawing/tests/test_pydot.py
+++ b/networkx/drawing/tests/test_pydot.py
@@ -151,3 +151,27 @@ def test_pydot_issue_258():
     G = nx.Graph([('"Example:A"', 1)])
     layout = nx.nx_pydot.pydot_layout(G)
     assert isinstance(layout, dict)
+
+
+@pytest.mark.parametrize(
+    "graph_type", [nx.Graph, nx.DiGraph, nx.MultiGraph, nx.MultiDiGraph]
+)
+def test_hashable_pydot(graph_type):
+    # gh-5790
+    G = graph_type()
+    G.add_edge("5", frozenset([1]), t='"Example:A"', l=False)
+    G.add_edge("1", 2, w=True, t=("node1",), l=frozenset(["node1"]))
+    G.add_edge("node", (3, 3), w="string")
+
+    assert [
+        {"t": '"Example:A"', "l": "False"},
+        {"w": "True", "t": "('node1',)", "l": "frozenset({'node1'})"},
+        {"w": "string"},
+    ] == [
+        attr
+        for _, _, attr in nx.nx_pydot.from_pydot(nx.nx_pydot.to_pydot(G)).edges.data()
+    ]
+
+    assert {str(i) for i in G.nodes()} == set(
+        nx.nx_pydot.from_pydot(nx.nx_pydot.to_pydot(G)).nodes
+    )