Merge fb87324 into 7c06dbd

holoviews/element/graphs.py

@@ -424,8 +424,10 @@ def __init__(self, data, kdims=None, vdims=None, **params):
             edges, nodes, edgepaths = data
         else:
             edges, nodes, edgepaths = data, None, None
+
+        super(TriMesh, self).__init__(edges, kdims=kdims, vdims=vdims, **params)
         if nodes is None:
-            if isinstance(edges, list) and len(edges) == 0:
+            if len(self) == 0:
                 nodes = []
             else:
                 raise ValueError("TriMesh expects both simplices and nodes "
@@ -452,7 +454,7 @@ def __init__(self, data, kdims=None, vdims=None, **params):
                                      "x/y positions and optionally the node indices.")
         if edgepaths is not None and not isinstance(edgepaths, self._edge_type):
             edgepaths = self._edge_type(edgepaths)
-        super(TriMesh, self).__init__(edges, kdims=kdims, vdims=vdims, **params)
+
         self._nodes = nodes
         self._edgepaths = edgepaths
 

tests/testgraphelement.py

@@ -138,6 +138,16 @@ def test_trimesh_constructor(self):
         self.assertEqual(trimesh.array(), np.array(self.simplices))
         self.assertEqual(trimesh.nodes.array(), np.array(self.nodes))
 
+    def test_trimesh_empty(self):
+        trimesh = TriMesh([])
+        self.assertEqual(trimesh.array(), np.empty((0, 3)))
+        self.assertEqual(trimesh.nodes.array(), np.empty((0, 3)))
+
+    def test_trimesh_empty_clone(self):
+        trimesh = TriMesh([]).clone()
+        self.assertEqual(trimesh.array(), np.empty((0, 3)))
+        self.assertEqual(trimesh.nodes.array(), np.empty((0, 3)))
+
     def test_trimesh_constructor_tuple_nodes(self):
         nodes = tuple(zip(*self.nodes))[:2]
         trimesh = TriMesh((self.simplices, nodes))