diff --git a/tests/test_undulator.py b/tests/test_undulator.py
new file mode 100644
index 0000000..cf346e2
--- /dev/null
+++ b/tests/test_undulator.py
@@ -0,0 +1,54 @@
+import threading
+from unittest import mock
+
+import ophyd
+import pytest
+
+from ophyd_devices.devices.undulator import UndulatorGap
+from ophyd_devices.tests.utils import MockPV, patch_dual_pvs
+
+
+@pytest.fixture(scope="function")
+def mock_undulator():
+    name = "undulator"
+    prefix = "TEST:UNDULATOR"
+    with mock.patch.object(ophyd, "cl") as mock_cl:
+        mock_cl.get_pv = MockPV
+        mock_cl.thread_class = threading.Thread
+        dev = UndulatorGap(name=name, prefix=prefix)
+        patch_dual_pvs(dev)
+        yield dev
+
+
+@pytest.mark.parametrize(
+    ["start", "end", "in_deadband_expected"],
+    [
+        (1.0, 1.0, True),
+        (0, 1.0, False),
+        (-0.004, 0.004, False),
+        (-0.0027, -0.0023, True),
+        (1, 1.0009, False),
+        (1, 1.0007, True),
+    ],
+)
+@mock.patch("ophyd_devices.devices.undulator.PVPositioner.move")
+@mock.patch("ophyd_devices.devices.undulator.MoveStatus")
+def test_instant_completion_within_deadband(
+    mock_movestatus, mock_super_move, mock_undulator, start, end, in_deadband_expected
+):
+    mock_undulator.select_control._read_pv.mock_data = 1
+    mock_undulator._position = start
+    mock_undulator.move(end)
+
+    if in_deadband_expected:
+        mock_movestatus.assert_called_with(mock.ANY, mock.ANY, done=True, success=True)
+    else:
+        mock_movestatus.assert_not_called()
+        mock_super_move.assert_called_once()
+
+
+def test_undulator_raises_when_disabled(mock_undulator):
+    mock_undulator.select_control._read_pv.mock_data = 0
+    with pytest.raises(Exception) as e:
+        mock_undulator.move(5)
+    assert e.match("Undulator is operator controlled!")