[python][RDF] Add tests for creating an RDataFrame from an empty array

Author: siliataider

bindings/pyroot/pythonizations/test/rdataframe_makenumpy.py

@@ -154,6 +154,16 @@ def test_sliced_array(self):
         self.assertEqual(list(x_col.GetValue()), [1,3])
         self.assertEqual(list(y_col.GetValue()), [2,4])
 
+    def test_empty_arrays(self):
+        """
+        Test creating an RDataFrame from an empty numpy array
+        """
+        data = {"x": np.array([], dtype="object")}
+        df = ROOT.RDF.FromNumpy(data)
+        colnames = df.GetColumnNames()
+        self.assertIn("x", colnames)
+        self.assertEqual(df.Count().GetValue(), 0)
+
 
 if __name__ == '__main__':
     unittest.main()