diff --git a/tests/tests_devices/test_delay_generator_csaxs.py b/tests/tests_devices/test_delay_generator_csaxs.py
index 18079c6..6ba4ecb 100644
--- a/tests/tests_devices/test_delay_generator_csaxs.py
+++ b/tests/tests_devices/test_delay_generator_csaxs.py
@@ -282,10 +282,11 @@ def test_ddg1_stage(mock_ddg1: DDG1):
 
     mock_ddg1.scan_info.msg.scan_parameters["exp_time"] = exp_time
     mock_ddg1.scan_info.msg.scan_parameters["frames_per_trigger"] = frames_per_trigger
+    mock_ddg1.fast_shutter_control._read_pv.mock_data = 0  # Simulate shutter control
 
     mock_ddg1.stage()
 
-    shutter_width = 2e-3 + exp_time * frames_per_trigger + 1e-3
+    shutter_width = mock_ddg1._shutter_to_open_delay + exp_time * frames_per_trigger
 
     assert np.isclose(mock_ddg1.burst_mode.get(), 1)  # burst mode is enabled
     assert np.isclose(mock_ddg1.burst_delay.get(), 0)
@@ -302,6 +303,25 @@ def test_ddg1_stage(mock_ddg1: DDG1):
     assert np.isclose(mock_ddg1.ef.width.get(), 1e-6)
 
     assert mock_ddg1.staged == ophyd.Staged.yes
+    mock_ddg1.unstage()
+
+    # Test if shutter is kept open..
+    mock_ddg1.fast_shutter_control._read_pv.mock_data = 1  # Simulate shutter control is kept open
+    # Test method
+    mock_ddg1.keep_shutter_open_during_scan(True)
+    shutter_width = mock_ddg1._shutter_to_open_delay + exp_time * frames_per_trigger
+    assert np.isclose(
+        shutter_width, exp_time * frames_per_trigger
+    )  # Shutter to open delay is not added as shutter is kept open
+    # Simulate fly scan, so no extra trigger for MCS card.
+    mock_ddg1.scan_info.msg.scan_type = "fly"
+    mock_ddg1.stage()
+    # Shutter channel cd
+    assert np.isclose(mock_ddg1.cd.delay.get(), 0)
+    assert np.isclose(mock_ddg1.cd.width.get(), shutter_width)
+    # MCS channel ef or gate
+    assert np.isclose(mock_ddg1.ef.delay.get(), 0)
+    assert np.isclose(mock_ddg1.ef.width.get(), 0)  # No triggering of MCS due to shutter fly scan
 
 
 def test_ddg1_on_trigger(mock_ddg1: DDG1):
@@ -331,9 +351,28 @@ def test_ddg1_on_trigger(mock_ddg1: DDG1):
     #################################
     with mock.patch.object(ddg, "_prepare_mcs_on_trigger") as mock_prepare_mcs:
         mock_prepare_mcs.return_value = ophyd.StatusBase(done=True, success=True)
+        # MCS card is present and enabled, should call prepare_mcs_on_trigger
+        # and the status should resolve once acuiring goes from 1 to 0.
         status = ddg.trigger()
+        assert status.done is False
+        mcs = ddg.device_manager.devices.get("mcs", None)
+        assert mcs is not None
+        mcs.acquiring._read_pv.mock_data = 1  # Simulate acquiring started
+        assert status.done is False
+        mcs.acquiring._read_pv.mock_data = 0  # Simulate acquiring stopped
+        status.wait(timeout=1)  # Wait for the status to be done
+        assert status.done is True
+        assert status.success is True
+        mock_prepare_mcs.assert_called_once()
 
+        # Now we disable the mcs card, and trigger again. This should not call prepare_mcs_on_trigger
+        # and should fallback to polling the DDG for END_OF_BURST status bit.
+
+        # Disable mcs card
+        mcs.enabled = False
+        status = ddg.trigger()
         # Check that the poll thread run event is set
+        # Careful in debugger, there is a timeout based on the exp_time + 5s default
         assert ddg._poll_thread_run_event.is_set()
         assert not ddg._poll_thread_poll_loop_done.is_set()