fix(scan_control): restore scan parameters from history are fetched on demand with button

tests/unit_tests/test_scan_control.py

@@ -503,12 +503,42 @@ def test_changing_scans_remember_parameters(scan_control, mocked_client):
     assert grid_kwargs["burst_at_each_point"] == kwargs["burst_at_each_point"]
 
 
+def test_scan_selection_does_not_fetch_last_scan_parameters(
+    scan_control, mocked_client, monkeypatch
+):
+    xread = MagicMock(wraps=mocked_client.connector.xread)
+    monkeypatch.setattr(mocked_client.connector, "xread", xread)
+
+    scan_control.comboBox_scan_selection.setCurrentText("grid_scan")
+
+    xread.assert_not_called()
+
+
+def test_restore_last_scan_parameters_button_fetches_on_demand(
+    scan_control, mocked_client, qtbot, monkeypatch
+):
+    scan_control.comboBox_scan_selection.setCurrentText("line_scan")
+    xread = MagicMock(wraps=mocked_client.connector.xread)
+    monkeypatch.setattr(mocked_client.connector, "xread", xread)
+
+    qtbot.mouseClick(scan_control.last_scan_button, Qt.LeftButton)
+
+    xread.assert_called_once_with(
+        MessageEndpoints.scan_history(), from_start=True, user_id=scan_control.object_name
+    )
+    args, kwargs = scan_control.get_scan_parameters(bec_object=False)
+    assert args == ["samx", 0.0, 2.0]
+    assert kwargs["steps"] == 10
+    assert kwargs["relative"] is False
+    assert kwargs["exp_time"] == 2
+
+
 @pytest.mark.skip(reason="Unreliable - GH issue #1134")
 def test_get_scan_parameters_from_redis(scan_control, mocked_client):
     scan_name = "line_scan"
     scan_control.comboBox_scan_selection.setCurrentText(scan_name)
 
-    scan_control.toggle.checked = True
+    scan_control.last_scan_button.click()
 
     args, kwargs = scan_control.get_scan_parameters(bec_object=False)
 
@@ -605,7 +635,7 @@ def test_restore_parameters_with_fewer_arg_bundles(scan_control, qtbot):
     assert scan_control.arg_box.count_arg_rows() == 3
 
     # Trigger restore of parameters from history
-    scan_control.toggle.checked = True
+    scan_control.last_scan_button.click()
     qtbot.wait(200)
 
     # After restore, arg_box should have only one bundle (the history size)