Add another test

tests/test_analyse_phonopy.py

@@ -1,6 +1,8 @@
 import unittest
 from ase.build import bulk
+import numpy as np
 from structuretoolkit.analyse.phonopy import get_equivalent_atoms
+from structuretoolkit.common.phonopy import atoms_to_phonopy, phonopy_to_atoms
 
 
 try:
@@ -14,9 +16,16 @@
 @unittest.skipIf(
     spglib_not_available, "spglib is not installed, so the spglib tests are skipped."
 )
-class TestEquivalentAtoms(unittest.TestCase):
+class TestPhonopyAtoms(unittest.TestCase):
     def test_get_equivalent_atoms(self):
         equivalent_atoms = get_equivalent_atoms(
             structure=bulk("Al", cubic=True), symprec=1e-5, angle_tolerance=-1.0
         )
         self.assertTrue(all(equivalent_atoms == [0, 0, 0, 0]))
+
+    def test_convert(self):
+        structure = bulk("Al", cubic=True)
+        structure_converted = phonopy_to_atoms(atoms_to_phonopy(structure))
+        self.assertTrue(np.all(structure.symbols == structure_converted.symbols))
+        self.assertTrue(np.all(structure.positions == structure_converted.positions))
+        self.assertTrue(np.all(structure.cell == structure_converted.cell))