diff --git a/tests/test_abstract_model.py b/tests/test_abstract_model.py
index 5d4d7c6..3c185ea 100644
--- a/tests/test_abstract_model.py
+++ b/tests/test_abstract_model.py
@@ -1,10 +1,15 @@
+import io
+
+import ase
 import pytest
+from pytest import approx
 
 from io import StringIO
-from ase.io import read
+from ase.io import read, write
 import numpy as np
 
 from abcd.model import AbstractModel
+from ase.calculators.lj import LennardJones
 
 
 @pytest.fixture
@@ -151,3 +156,101 @@ def test_to_ase_no_results(extxyz_file):
     assert new_atoms.info["formula"] == atoms.get_chemical_formula()
 
     assert new_atoms.calc is None
+
+
+def test_from_atoms_len_atoms_3():
+    atoms = ase.Atoms(
+        "H3",
+        positions=[[0, 0, 0], [0, 0, 1], [0, 1, 0]],
+        pbc=True,
+        cell=[2, 2, 2],
+    )
+    atoms.calc = LennardJones()
+    atoms.calc.calculate(atoms)
+
+    # convert
+    abcd_data = AbstractModel.from_atoms(atoms, store_calc=True)
+
+    assert set(abcd_data.info_keys) == {
+        "pbc",
+        "n_atoms",
+        "cell",
+        "formula",
+        "calculator_name",
+        "calculator_parameters",
+    }
+    assert set(abcd_data.arrays_keys) == {"numbers", "positions"}
+    assert set(abcd_data.results_keys) == {
+        "stress",
+        "energy",
+        "forces",
+        "energies",
+        "stresses",
+        "free_energy",
+    }
+
+    # check a some keys as well
+    assert abcd_data["energy"] == atoms.get_potential_energy()
+    assert abcd_data["forces"] == approx(atoms.get_forces())
+
+
+@pytest.mark.parametrize("store_calc", [True, False])
+def test_write_and_read(store_calc):
+    # create atoms & add a calculator
+    atoms = ase.Atoms(
+        "H3",
+        positions=[[0, 0, 0], [0, 0, 1], [0, 1, 0]],
+        pbc=True,
+        cell=[2, 2, 2],
+    )
+    atoms.calc = LennardJones()
+    atoms.calc.calculate(atoms)
+
+    # dump to XYZ
+    buffer = io.StringIO()
+    write(buffer, atoms, format="extxyz")
+
+    # read back
+    buffer.seek(0)
+    atoms_read = read(buffer, format="extxyz")
+
+    # read in both of them
+    abcd_data = AbstractModel.from_atoms(atoms, store_calc=store_calc)
+    abcd_data_after_read = AbstractModel.from_atoms(atoms_read, store_calc=store_calc)
+
+    # check that all results are the same
+    for key in ["info_keys", "arrays_keys", "derived_keys", "results_keys"]:
+        assert set(getattr(abcd_data, key)) == set(
+            getattr(abcd_data_after_read, key)
+        ), f"{key} mismatched"
+
+    # info & arrays same, except calc recognised as LJ when not from XYZ
+    for key in set(abcd_data.info_keys + abcd_data.arrays_keys) - {
+        "calculator_name",
+        "calculator_parameters",
+    }:
+        assert (
+            abcd_data[key] == abcd_data_after_read[key]
+        ), f"{key}'s value does not match"
+
+    # date & hashed will differ
+    for key in set(abcd_data.derived_keys) - {
+        "hash",
+        "modified",
+        "uploaded",
+        "hash_structure",  # see issue #118
+    }:
+        assert (
+            abcd_data[key] == abcd_data_after_read[key]
+        ), f"{key}'s value does not match"
+
+    # expected differences - n.b. order of calls above
+    assert abcd_data_after_read["modified"] > abcd_data["modified"]
+    assert abcd_data_after_read["uploaded"] > abcd_data["uploaded"]
+    assert abcd_data_after_read["hash"] != abcd_data["hash"]
+
+    # expect results to match within fp precision
+    for key in set(abcd_data.results_keys):
+        assert abcd_data[key] == approx(
+            np.array(abcd_data_after_read[key])
+        ), f"{key}'s value does not match"