add test for tagged traversal

tests/traversal/test_tagging_traversal.py

@@ -3,27 +3,26 @@
 import bw2data as bd
 import pytest
 
-from bw_graph_tools import NewNodeEachVisitGraphTraversal
 from bw_graph_tools.graph_traversal import (
     GraphTraversalSettings,
+    NewNodeEachVisitGraphTraversal,
     NewNodeEachVisitTaggedGraphTraversal,
+    SameNodeEachVisitTaggedGraphTraversal,
     TaggedGraphTraversalSettings,
 )
 from bw_graph_tools.graph_traversal.graph_objects import Edge, GroupedNodes, Node
 from bw_graph_tools.graph_traversal.utils import Counter
 
 
-def get_default_graph(lca, tags):
-    return NewNodeEachVisitTaggedGraphTraversal(
+def get_default_graph(lca, tags, variant=NewNodeEachVisitTaggedGraphTraversal):
+    return variant(
         lca=lca,
         settings=TaggedGraphTraversalSettings(cutoff=0.001, max_calc=10, tags=tags),
     )
 
 
-def get_untagged_new_graph(lca):
-    return NewNodeEachVisitGraphTraversal(
-        lca=lca, settings=GraphTraversalSettings(cutoff=0.001, max_calc=10)
-    )
+def get_untagged_new_graph(lca, variant=NewNodeEachVisitGraphTraversal):
+    return variant(lca=lca, settings=GraphTraversalSettings(cutoff=0.001, max_calc=10))
 
 
 @pytest.fixture
@@ -32,6 +31,16 @@ def graph(sample_database_with_tagged_products):
     yield g
 
 
+@pytest.fixture
+def same_node_graph(sample_database_with_tagged_products):
+    g: SameNodeEachVisitTaggedGraphTraversal = get_default_graph(
+        sample_database_with_tagged_products,
+        ["test"],
+        variant=SameNodeEachVisitTaggedGraphTraversal,
+    )
+    yield g
+
+
 class Faker:
     @staticmethod
     def generate_list_from_bwdata_names(items):
@@ -200,3 +209,24 @@ def test_tagged_traversal(self, graph, sample_database_with_tagged_products):
 
         assert len(groups["test: group-a"][0].nodes) == 1
         assert len(groups["test: group-b"][0].nodes) == 3
+
+
+class TestSameNodeTaggingTraversal:
+    @staticmethod
+    def count_grouped_nodes(some_graph):
+        return sum(
+            [1 if isinstance(node, GroupedNodes) else 0 for node in some_graph.nodes.values()]
+        )
+
+    def test_tagged_traversal(self, same_node_graph):
+        same_node_graph.traverse(depth=2)
+        assert len(same_node_graph.nodes) == 5, "Expecting 5 nodes in the graph"
+        assert self.count_grouped_nodes(same_node_graph) == 2, "Expecting to find two grouped nodes"
+
+        gn = same_node_graph.nodes[7]
+        assert isinstance(gn, GroupedNodes), "Expecting a grouped node"
+        assert len(gn.nodes) == 1, "Expecting only one node in the group"
+        same_node_graph.traverse_from_node(gn, depth=1)
+        count_of_grouped_nodes = self.count_grouped_nodes(same_node_graph)
+        assert count_of_grouped_nodes == 1, "Expecting only one grouped node"
+        assert len(same_node_graph.nodes) == 5, "Expecting 5 nodes only"