diff --git a/python/tests/closed_orbit_test.py b/python/tests/closed_orbit_test.py
index ca844922..4445a181 100644
--- a/python/tests/closed_orbit_test.py
+++ b/python/tests/closed_orbit_test.py
@@ -14,7 +14,13 @@
 import gtpsa
 from thor_scsi.factory import accelerator_from_config
 from thor_scsi.utils.closed_orbit import compute_closed_orbit
+from thor_scsi.utils import canonical_variables_mapping_default
 
+from thor_scsi.utils.accelerator import (
+    instrument_with_standard_observers,
+    extract_orbit_from_standard_observers,
+    extract_orbit_from_accelerator_with_standard_observers,
+)
 
 path = (
     Path(os.path.dirname(__file__))
@@ -28,6 +34,7 @@ def create_acc():
 
 
 def test10_closed_orbit_for_zero():
+
     calc_config = tslib.ConfigType()
     acc = create_acc()
 
@@ -56,6 +63,20 @@ def test10_closed_orbit_for_zero():
     assert x0.ct == pytest.approx(ct_save, abs=1e-9)
 
 
+def test20_closed_orbit_for_zero_ovservers():
+    """test functions used by twin
+
+    just that they execute without error
+    """
+    calc_config = tslib.ConfigType()
+    acc = create_acc()
+    observers_non_perturbated = instrument_with_standard_observers(
+        acc, mapping=canonical_variables_mapping_default
+    )
+    result = compute_closed_orbit(acc, calc_config, delta=0e0)
+    assert result.found_closed_orbit == True
+    extract_orbit_from_accelerator_with_standard_observers(acc)
+
 def compensate_quadrupole_offset_with_dipole_kick(quad):
     dx = quad.get_dx()
     assert quad.get_main_multipole_number() == 2
diff --git a/python/tests/twiss_test.py b/python/tests/twiss_test.py
new file mode 100644
index 00000000..21ef7092
--- /dev/null
+++ b/python/tests/twiss_test.py
@@ -0,0 +1,51 @@
+from thor_scsi.utils import canonical_variables_mapping_default
+from thor_scsi.utils.linear_optics import compute_Twiss_along_lattice
+from thor_scsi.factory import accelerator_from_config
+from thor_scsi import lib as tslib
+import gtpsa
+import pytest
+from pathlib import Path
+import os.path
+
+desc = gtpsa.desc(6, 1)
+
+path = (
+    Path(os.path.dirname(__file__))
+    / "lattices"
+    / "b2_stduser_beamports_blm_tracy_corr.lat"
+)
+
+
+def create_acc():
+    acc = accelerator_from_config(path)
+    acc.set_log_level(tslib.accelerator_log_level.warning)
+    return acc
+
+
+def test_twiss_without_radiation():
+    """Functions as used by digital twin"""
+    n_dof = 2
+    calc_config = tslib.ConfigType()
+    calc_config.radiation = False
+    calc_config.Cavity_on = False
+    acc = create_acc()
+    compute_Twiss_along_lattice(
+        n_dof, acc, calc_config, desc=desc, mapping=canonical_variables_mapping_default
+    )
+
+
+@pytest.mark.skip
+def test_twiss_with_radiation():
+    """Functions as used by digital twin
+
+    just check that it runs
+    """
+    calc_config = tslib.ConfigType()
+    n_dof = 3
+    calc_config.radiation = True
+    calc_config.Cavity_on = True
+    calc_config.Energy = 2.7
+    acc = create_acc()
+    compute_Twiss_along_lattice(
+        n_dof, acc, calc_config, desc=desc, mapping=canonical_variables_mapping_default
+    )