--- a
+++ b/tests/test_utils.py
@@ -0,0 +1,65 @@
+import os
+import pytest
+
+import oddt
+from oddt.utils import check_molecule, chunker, compose_iter
+
+test_data_dir = os.path.dirname(os.path.abspath(__file__))
+
+# common file names
+dude_data_dir = os.path.join(test_data_dir, 'data', 'dude', 'xiap')
+xiap_crystal_ligand = os.path.join(dude_data_dir, 'crystal_ligand.sdf')
+xiap_protein = os.path.join(dude_data_dir, 'receptor_rdkit.pdb')
+
+
+def test_check_molecule():
+    with pytest.raises(ValueError, match='Molecule object'):
+        check_molecule([])
+
+    ligand = next(oddt.toolkit.readfile('sdf', xiap_crystal_ligand))
+    check_molecule(ligand)
+
+    # force protein
+    protein = next(oddt.toolkit.readfile('pdb', xiap_protein))
+    with pytest.raises(ValueError, match='marked as a protein'):
+        check_molecule(protein, force_protein=True)
+
+    protein.protein = True
+    check_molecule(protein, force_protein=True)
+
+    # force coordinates
+    mol = oddt.toolkit.readstring('smi', 'c1ccccc1')
+    with pytest.raises(ValueError, match='3D coordinates'):
+        check_molecule(mol, force_coords=True)
+
+    mol.make3D()
+    check_molecule(mol, force_coords=True)
+
+    # with pytest.raises(ValueError, match='positional'):
+    #     check_molecule(mol, True)
+
+    mol = oddt.toolkit.readstring('sdf', '''mol_title
+ handmade
+
+  0  0  0  0  0  0  0  0  0  0999 V2000
+M  END
+                          ''')
+    with pytest.raises(ValueError, match='has zero atoms'):
+        check_molecule(mol, non_zero_atoms=True)
+
+
+def test_func_composition():
+    def double(x):
+        return [i * 2 for i in x]
+
+    def inc(x):
+        return [i + 1 for i in x]
+
+    assert compose_iter([1], funcs=[double, inc]) == [3]
+    assert compose_iter([3], funcs=[double, inc]) == [7]
+    assert compose_iter([10], funcs=[double, inc]) == [21]
+
+
+def test_chunks():
+    chunks = chunker('ABCDEFG', 2)
+    assert list(chunks), [['A', 'B'], ['C', 'D'], ['E', 'F'] == ['G']]