--- a
+++ b/test/data/test_molecule.py
@@ -0,0 +1,41 @@
+import unittest
+
+import torch
+
+from torchdrug import data
+
+
+class MoleculeTest(unittest.TestCase):
+
+    def setUp(self):
+        self.smiles = "CCC(CC)COC(=O)[C@H](C)N[P@](=O)(OC[C@H]1O[C@](C#N)" \
+                      "([C@H](O)[C@@H]1O)C1=CC=C2N1N=CN=C2N)OC1=CC=CC=C1"
+
+    def test_smiles(self):
+        mol = data.Molecule.from_smiles(self.smiles)
+        smiles = mol.to_smiles().upper()
+        carbon_result = (mol.atom_type == 6).sum().item()
+        carbon_truth = self.smiles.count("C")
+        atom_result = mol.num_atom
+        atom_truth = self.smiles.count("C") + self.smiles.count("O") + self.smiles.count("N") + self.smiles.count("P")
+        self.assertEqual(carbon_result, carbon_truth, "Incorrect SMILES construction")
+        self.assertEqual(atom_result, atom_truth, "Incorrect SMILES construction")
+        carbon_result = smiles.count("C")
+        atom_result = smiles.count("C") + smiles.count("O") + smiles.count("N") + smiles.count("P")
+        self.assertEqual(carbon_result, carbon_truth, "Incorrect SMILES construction")
+        self.assertEqual(atom_result, atom_truth, "Incorrect SMILES construction")
+
+        mol = data.Molecule.from_smiles("")
+        self.assertEqual(mol.num_node, 0, "Incorrect SMILES side case")
+        self.assertEqual(mol.num_edge, 0, "Incorrect SMILES side case")
+        mols = data.PackedMolecule.from_smiles([""])
+        self.assertTrue((mols.num_nodes == 0).all(), "Incorrect SMILES side case")
+        self.assertTrue((mols.num_edges == 0).all(), "Incorrect SMILES side case")
+
+    def test_feature(self):
+        mol = data.Molecule.from_smiles(self.smiles, mol_feature="ecfp")
+        self.assertTrue((mol.graph_feature > 0).any(), "Incorrect ECFP feature")
+
+
+if __name__ == "__main__":
+    unittest.main()
\ No newline at end of file