diff --git a/src/kg_topology_toolbox/topology_toolbox.py b/src/kg_topology_toolbox/topology_toolbox.py
index 5def422..faec2a9 100644
--- a/src/kg_topology_toolbox/topology_toolbox.py
+++ b/src/kg_topology_toolbox/topology_toolbox.py
@@ -278,9 +278,9 @@ def edge_metapath_count(
         composition_workers: int = min(32, mp.cpu_count() - 1 or 1),
     ) -> pd.DataFrame:
         """
-        For each edge in the KG, compute the number of triangles of different
-        metapaths (i.e., the unique tuples (r1, r2) of relation types
-        of the two additional edges of the triangle).
+        For each edge in the KG, compute the number of triangles supported on it
+        distinguishing between different metapaths (i.e., the unique tuples (r1, r2)
+        of relation types of the two additional edges of the triangle).
 
         :param filter_relations:
             If not empty, compute the output only for the edges with relation
@@ -293,10 +293,11 @@ def edge_metapath_count(
             on number of available threads (max: 32).
 
         :return:
-            The output dataframe has one row for each (h, t, r1, r2) such that
-            there exists at least one triangle of metapath (r1, r2) over (any) edge
-            connecting h, t.
+            The output dataframe has one row for each (h, r, t, r1, r2) such that
+            there exists at least one triangle of metapath (r1, r2) over (h, r, t).
             The number of metapath triangles is given in the column **n_triangles**.
+            The column **index** provides the index of the edge (h, r, t) in the
+            original Knowledge Graph dataframe.
         """
         # discard loops as edges of a triangle
         df_wo_loops = self.df[self.df.h != self.df.t]
@@ -313,7 +314,7 @@ def edge_metapath_count(
             rel_df = self.df
             df_triangles = df_wo_loops
 
-        return composition_count(
+        counts = composition_count(
             df_triangles,
             chunk_size=composition_chunk_size,
             workers=composition_workers,
@@ -321,6 +322,8 @@ def edge_metapath_count(
             directed=True,
         )
 
+        return rel_df.reset_index().merge(counts, on=["h", "t"], how="inner")
+
     def edge_degree_cardinality_summary(
         self, filter_relations: list[int] = [], aggregate_by_r: bool = False
     ) -> pd.DataFrame:
diff --git a/tests/test_edge_topology_toolbox.py b/tests/test_edge_topology_toolbox.py
index 6e0b6be..49bfa5e 100644
--- a/tests/test_edge_topology_toolbox.py
+++ b/tests/test_edge_topology_toolbox.py
@@ -22,12 +22,19 @@
 )
 
 
-@pytest.mark.parametrize("return_metapath_list", [True, False])
-def test_small_graph_metrics(return_metapath_list: bool) -> None:
-    # Define a small graph with all the features tested by
-    # the edge_topology_toolbox
+def test_edge_metapath_count() -> None:
+    res = kgtt.edge_metapath_count()
+    assert np.allclose(res["index"], [2, 2])
+    assert np.allclose(res["h"], [0, 0])
+    assert np.allclose(res["r"], [0, 0])
+    assert np.allclose(res["t"], [2, 2])
+    assert np.allclose(res["r1"], [0, 1])
+    assert np.allclose(res["r2"], [1, 1])
+    assert np.allclose(res["n_triangles"], [1, 1])
+
 
-    # entity degrees statistics
+def test_edge_degree_cardinality_summary() -> None:
+    # edge degrees statistics
     res = kgtt.edge_degree_cardinality_summary()
     assert np.allclose(res["h_unique_rel"], [2, 2, 2, 1, 2, 2, 1, 2])
     assert np.allclose(res["h_degree"], [3, 3, 3, 2, 3, 3, 2, 3])
@@ -60,6 +67,9 @@ def test_small_graph_metrics(return_metapath_list: bool) -> None:
         "M:M",
     ]
 
+
+@pytest.mark.parametrize("return_metapath_list", [True, False])
+def test_edge_pattern_summary(return_metapath_list: bool) -> None:
     # relation pattern symmetry
     res = kgtt.edge_pattern_summary(return_metapath_list=return_metapath_list)
     assert np.allclose(
@@ -92,6 +102,7 @@ def test_small_graph_metrics(return_metapath_list: bool) -> None:
 def test_filter_relations() -> None:
     for rels in [[0], [1], [0, 1]]:
         for method in [
+            kgtt.edge_metapath_count,
             kgtt.edge_degree_cardinality_summary,
             partial(kgtt.edge_pattern_summary, return_metapath_list=True),
         ]:
diff --git a/tests/test_node_topology_toolbox.py b/tests/test_node_topology_toolbox.py
index 18d87ed..d002b41 100644
--- a/tests/test_node_topology_toolbox.py
+++ b/tests/test_node_topology_toolbox.py
@@ -19,10 +19,7 @@
 
 
 @pytest.mark.parametrize("return_relation_list", [True, False])
-def test_small_graph_metrics(return_relation_list: bool) -> None:
-    # Define a small graph with all the features tested by
-    # the node_topology_toolbox
-
+def test_node_degree_summary(return_relation_list: bool) -> None:
     # entity degrees statistics
     res = kgtt.node_degree_summary(return_relation_list=return_relation_list)
     assert np.allclose(res["h_degree"], [3, 1, 3])
diff --git a/tests/test_relation_topology_toolbox.py b/tests/test_relation_topology_toolbox.py
index 3f0c05c..e527a5f 100644
--- a/tests/test_relation_topology_toolbox.py
+++ b/tests/test_relation_topology_toolbox.py
@@ -20,10 +20,7 @@
 kgtt = KGTopologyToolbox(df, head_column="H", relation_column="R", tail_column="T")
 
 
-def test_small_graph_metrics() -> None:
-    # Define a small graph on five nodes with all the features tested by
-    # the relation_topology_toolbox
-
+def test_aggregate_by_r() -> None:
     dcs = kgtt.edge_degree_cardinality_summary(aggregate_by_r=True)
     eps = kgtt.edge_pattern_summary(return_metapath_list=True, aggregate_by_r=True)