--- a
+++ b/tests/utils.py
@@ -0,0 +1,17 @@
+"""Common utils for testing purposes"""
+from random import shuffle
+
+import oddt
+from oddt.utils import is_openbabel_molecule
+
+
+def shuffle_mol(mol):
+    """Randomly reorder molecule atoms and return a shuffled copy of input."""
+    new_mol = mol.clone
+    new_order = list(range(len(mol.atoms)))
+    shuffle(new_order)
+    if is_openbabel_molecule(mol):
+        new_mol.OBMol.RenumberAtoms([i + 1 for i in new_order])
+    else:
+        new_mol.Mol = oddt.toolkits.rdk.Chem.RenumberAtoms(new_mol.Mol, new_order)
+    return new_mol