diff --git a/rascal2/widgets/__init__.py b/rascal2/widgets/__init__.py
index 92ec968e..dab74dc0 100644
--- a/rascal2/widgets/__init__.py
+++ b/rascal2/widgets/__init__.py
@@ -1,5 +1,12 @@
 from rascal2.widgets.controls import ControlsWidget
-from rascal2.widgets.inputs import AdaptiveDoubleSpinBox, MultiSelectComboBox, MultiSelectList, get_validated_input
+from rascal2.widgets.inputs import (
+    AdaptiveDoubleSpinBox,
+    MultiSelectComboBox,
+    MultiSelectList,
+    PathWidget,
+    ProgressButton,
+    get_validated_input,
+)
 from rascal2.widgets.plot import PlotWidget
 from rascal2.widgets.project.slider_view import SliderViewWidget
 from rascal2.widgets.terminal import TerminalWidget
@@ -10,7 +17,9 @@
     "get_validated_input",
     "MultiSelectComboBox",
     "MultiSelectList",
+    "PathWidget",
     "PlotWidget",
+    "ProgressButton",
     "TerminalWidget",
     "SliderViewWidget",
 ]
diff --git a/tests/conftest.py b/tests/conftest.py
index ff31b498..a50fc024 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -1,7 +1,9 @@
+import os
 import tempfile
 from pathlib import Path
-from unittest.mock import patch
+from unittest.mock import MagicMock, patch
 
+os.environ["DELAY_MATLAB_START"] = "1"
 import pytest
 from PyQt6 import QtCore, QtWidgets
 
@@ -19,6 +21,11 @@ def global_setting():
     return GLOBAL_SETTING
 
 
+@pytest.fixture
+def mock_window_view():
+    return MockWindowView()
+
+
 @pytest.fixture(scope="session", autouse=True)
 def mock_setting(request):
     global GLOBAL_SETTING
@@ -38,3 +45,40 @@ def teardown_mock_setting():
             target.stop()
 
     request.addfinalizer(teardown_mock_setting)
+
+
+class MockUndoStack:
+    """A mock Undo stack."""
+
+    def __init__(self):
+        self.stack = []
+        self.clean = True
+
+    def push(self, command):
+        self.clean = False
+        command.redo()
+
+    def setClean(self):
+        self.clean = True
+
+    def isClean(self):
+        return self.clean
+
+
+class MockWindowView(QtWidgets.QMainWindow):
+    """A mock MainWindowView class."""
+
+    def __init__(self):
+        super().__init__()
+        self.undo_stack = MockUndoStack()
+        self.presenter = MagicMock()
+        self.controls_widget = MagicMock()
+        self.project_widget = MagicMock()
+        self.terminal_widget = MagicMock()
+        self.plot_widget = MagicMock()
+        self.handle_results = MagicMock()
+        self.settings = MagicMock()
+        self.get_project_folder = lambda: "new path/"
+        self.windowTitle = lambda: "RasCAL2"
+        self.show_message = MagicMock()
+        self.toggle_sliders = MagicMock()
diff --git a/tests/core/test_commands.py b/tests/core/test_commands.py
new file mode 100644
index 00000000..7421e937
--- /dev/null
+++ b/tests/core/test_commands.py
@@ -0,0 +1,90 @@
+"""Tests for the undo Command classes."""
+
+from unittest.mock import MagicMock, patch
+
+import pytest
+from ratapi import Controls, Project
+from ratapi.rat_core import ProblemDefinition
+
+from rascal2.core.commands import CommandID, EditControls, EditProject, SaveCalculationOutputs
+from rascal2.ui.presenter import MainWindowPresenter
+
+
+@pytest.fixture
+def presenter(mock_window_view):
+    with (
+        patch("rascal2.ui.presenter.LOGGER", autospec=True),
+        patch("rascal2.ui.model.os.chdir", autospec=True),
+    ):
+        pr = MainWindowPresenter(mock_window_view)
+        results = MagicMock()
+        results.calculationResults.sumChi = 45
+        pr.quick_run = MagicMock(return_value=results)
+        pr.model.controls = Controls()
+        pr.model.project = Project()
+        pr.model.results = None
+        pr.model.result_log = ""
+
+        yield pr
+
+
+def test_edit_controls(presenter):
+    command = EditControls({"procedure": "de", "targetValue": 3}, presenter)
+    assert command.id() == CommandID.EditControls
+    assert presenter.model.controls.procedure == "calculate"
+    assert presenter.model.controls.targetValue == 1
+    command.redo()
+    assert presenter.model.controls.procedure == "de"
+    assert presenter.model.controls.targetValue == 3
+    command.undo()
+    assert presenter.model.controls.procedure == "calculate"
+    assert presenter.model.controls.targetValue == 1
+
+
+def test_edit_project(presenter):
+    command = EditProject({"model": "custom layers"}, presenter)
+    assert command.id() == CommandID.EditProject
+    assert presenter.model.project.model == "standard layers"
+    command.redo()
+    assert presenter.model.project.model == "custom layers"
+    command.undo()
+    assert presenter.model.project.model == "standard layers"
+
+
+def test_edit_project_preview(presenter):
+    command = EditProject({"model": "custom layers"}, presenter, preview=True)
+    command.redo()
+    presenter.quick_run.assert_called_once()
+    assert presenter.model.results.calculationResults.sumChi == 45
+    command.undo()
+    assert presenter.model.results is None
+    command.redo()
+    # confirm quick_run is always done once
+    presenter.quick_run.assert_called_once()
+    assert presenter.model.results.calculationResults.sumChi == 45
+
+    presenter.quick_run.side_effect = ValueError("calculate error")
+    command = EditProject({"model": "custom layers"}, presenter, preview=True)
+    command.redo()
+    # run failed so result is None
+    assert command.new_result is None
+
+
+def test_save_calculation_outputs(presenter):
+    project = ProblemDefinition()
+    project.params = [4.5]
+    results = MagicMock()
+    results.calculationResults.sumChi = 45
+    log = "Stuff happened during calculation"
+    command = SaveCalculationOutputs(project, results, log, presenter)
+    assert presenter.model.project.parameters[0].value == 3
+    assert presenter.model.results is None
+    assert presenter.model.result_log == ""
+    command.redo()
+    assert presenter.model.project.parameters[0].value == 4.5
+    assert presenter.model.results.calculationResults.sumChi == 45
+    assert presenter.model.result_log == log
+    command.undo()
+    assert presenter.model.project.parameters[0].value == 3
+    assert presenter.model.results is None
+    assert presenter.model.result_log == ""
diff --git a/tests/dialogs/test_about_dialog.py b/tests/dialogs/test_about_dialog.py
index f621fb84..1f83b3c3 100644
--- a/tests/dialogs/test_about_dialog.py
+++ b/tests/dialogs/test_about_dialog.py
@@ -8,7 +8,9 @@
 @patch("rascal2.dialogs.about_dialog.MatlabHelper", autospec=True)
 def test_update_info_works(mock_matlab):
     """Check if `update_rascal_info` adds all necessary information to the dialog."""
-    mock_matlab.return_value = MagicMock()
+    helper = MagicMock()
+    mock_matlab.return_value = helper
+    helper.get_matlab_path.return_value = "Test_Path"
     parent = QtWidgets.QMainWindow()
     about = AboutDialog(parent)
     assert about._rascal_label.text() == "information about RASCAL-2"
@@ -17,5 +19,9 @@ def test_update_info_works(mock_matlab):
     rascal_info = about._rascal_label.text()
     assert "Version" in rascal_info
     assert "RasCAL 2" in rascal_info
-    assert "Matlab Path:" in rascal_info
+    assert "Matlab Path:</td><td>Test_Path" in rascal_info
     assert "Log File:" in rascal_info
+
+    helper.get_matlab_path.return_value = ""
+    about.update_rascal_info()
+    assert "Matlab Path:</td><td>None" in about._rascal_label.text()
diff --git a/tests/core/test_settings.py b/tests/test_settings.py
similarity index 100%
rename from tests/core/test_settings.py
rename to tests/test_settings.py
diff --git a/tests/ui/test_presenter.py b/tests/ui/test_presenter.py
index 0d85e053..d99d664f 100644
--- a/tests/ui/test_presenter.py
+++ b/tests/ui/test_presenter.py
@@ -49,12 +49,12 @@ def __init__(self):
 
 
 @pytest.fixture
-def presenter():
+def presenter(mock_window_view):
     with (
         patch("rascal2.ui.presenter.LOGGER", autospec=True) as mock_log,
         patch("rascal2.ui.model.os.chdir", autospec=True),
     ):
-        pr = MainWindowPresenter(MockWindowView())
+        pr = MainWindowPresenter(mock_window_view)
         pr.runner = MagicMock()
         pr.model.controls = Controls()
         pr.model.project = MagicMock()
diff --git a/tests/widgets/project/test_project.py b/tests/widgets/project/test_project.py
index 493e4b43..075ae747 100644
--- a/tests/widgets/project/test_project.py
+++ b/tests/widgets/project/test_project.py
@@ -7,12 +7,7 @@
 from ratapi.utils.enums import Calculations, Geometries, LayerModels
 
 from rascal2.widgets.project.project import ProjectTabWidget, ProjectWidget, create_draft_project
-from rascal2.widgets.project.tables import (
-    ClassListTableModel,
-    ParameterFieldWidget,
-    ParametersModel,
-    ProjectFieldWidget,
-)
+from rascal2.widgets.project.tables import ParameterFieldWidget, ProjectFieldWidget
 
 
 class MockModel(QtCore.QObject):
@@ -31,15 +26,6 @@ def __init__(self):
         self.edit_project = MagicMock()
 
 
-class MockMainWindow(QtWidgets.QMainWindow):
-    def __init__(self):
-        super().__init__()
-        self.presenter = MockPresenter()
-        self.controls_widget = MagicMock()
-        self.project_widget = None
-        self.toggle_sliders = MagicMock()
-
-
 class DataModel(pydantic.BaseModel, validate_assignment=True):
     """Test Pydantic model."""
 
@@ -47,9 +33,6 @@ class DataModel(pydantic.BaseModel, validate_assignment=True):
     value: int = 15
 
 
-parent = MockMainWindow()
-
-
 @pytest.fixture
 def classlist():
     """Test ClassList."""
@@ -57,23 +40,17 @@ def classlist():
 
 
 @pytest.fixture
-def table_model(classlist):
-    """Test ClassListTableModel."""
-    return ClassListTableModel(classlist, parent)
-
-
-@pytest.fixture
-def setup_project_widget():
-    parent = MockMainWindow()
-    project_widget = ProjectWidget(parent)
+def project_widget(mock_window_view):
+    mock_window_view.presenter = MockPresenter()
+    project_widget = ProjectWidget(mock_window_view)
     project_widget.update_project_view()
     return project_widget
 
 
 @pytest.fixture
-def project_with_draft():
+def project_with_draft(mock_window_view):
     draft = create_draft_project(ratapi.Project())
-    project = ProjectWidget(parent)
+    project = ProjectWidget(mock_window_view)
     project.draft_project = draft
     return project
 
@@ -91,19 +68,8 @@ def _classlist(protected_indices):
     return _classlist
 
 
-@pytest.fixture
-def param_model(param_classlist):
-    def _param_model(protected_indices):
-        model = ParametersModel(param_classlist(protected_indices), parent)
-        return model
-
-    return _param_model
-
-
-def test_project_widget_initial_state(setup_project_widget):
-    """Tests the inital state of the ProjectWidget class."""
-    project_widget = setup_project_widget
-
+def test_project_widget_initial_state(project_widget):
+    """Tests the initial state of the ProjectWidget class."""
     # Check the layout of the project view
     assert project_widget.stacked_widget.currentIndex() == 0
 
@@ -146,10 +112,8 @@ def test_project_widget_initial_state(setup_project_widget):
     assert project_widget.edit_project_tab.currentIndex() == 0
 
 
-def test_edit_cancel_button_toggle(setup_project_widget):
+def test_edit_cancel_button_toggle(project_widget):
     """Tests clicking the edit button causes the stacked widget to change state."""
-    project_widget = setup_project_widget
-
     assert project_widget.stacked_widget.currentIndex() == 0
     project_widget.edit_project_button.click()
     assert project_widget.stacked_widget.currentIndex() == 1
@@ -166,10 +130,24 @@ def test_edit_cancel_button_toggle(setup_project_widget):
     assert project_widget.calculation_type.text() == Calculations.Normal
 
 
-def test_save_changes_to_model_project(setup_project_widget):
-    """Tests that making changes to the project settings."""
-    project_widget = setup_project_widget
+def test_show_slider_view(project_widget):
+    assert project_widget.stacked_widget.currentIndex() == 0
+    project_widget.show_slider_view()
+    assert project_widget.stacked_widget.currentIndex() == 2
+    slider_view = project_widget.stacked_widget.currentWidget()
+    assert len(slider_view.parameters) == 1
 
+    project_widget.parent_model.project.parameters.append(name="test", fit=True)
+    project_widget.update_slider_view()
+
+    # show slider creates a new slider
+    project_widget.show_slider_view()
+    slider_view_2 = project_widget.stacked_widget.currentWidget()
+    assert len(slider_view_2.parameters) == 2
+
+
+def test_save_changes_to_model_project(project_widget):
+    """Tests that making changes to the project settings."""
     project_widget.edit_project_button.click()
 
     project_widget.calculation_combobox.setCurrentText(Calculations.Domains)
@@ -184,10 +162,8 @@ def test_save_changes_to_model_project(setup_project_widget):
     assert project_widget.parent.presenter.edit_project.call_count == 1
 
 
-def test_cancel_changes_to_model_project(setup_project_widget):
+def test_cancel_changes_to_model_project(project_widget):
     """Tests that making changes to the project settings and not saving them reverts the changes."""
-    project_widget = setup_project_widget
-
     project_widget.edit_project_button.click()
 
     project_widget.calculation_combobox.setCurrentText(Calculations.Domains)
@@ -209,9 +185,8 @@ def test_cancel_changes_to_model_project(setup_project_widget):
     assert project_widget.geometry_type.text() == Geometries.AirSubstrate
 
 
-def test_domains_tab(setup_project_widget):
+def test_domains_tab(project_widget):
     """Tests that domain tab is visible."""
-    project_widget = setup_project_widget
     project_widget.edit_project_button.click()
     project_widget.calculation_combobox.setCurrentText(Calculations.Domains)
     assert project_widget.draft_project["calculation"] == Calculations.Domains
@@ -222,11 +197,11 @@ def test_domains_tab(setup_project_widget):
     assert project_widget.edit_project_tab.isTabVisible(domains_tab_index)
 
 
-def test_project_tab_init():
+def test_project_tab_init(mock_window_view):
     """Test that the project tab correctly creates field widgets."""
     fields = ["my_field", "parameters", "bulk_in"]
 
-    tab = ProjectTabWidget(fields, parent)
+    tab = ProjectTabWidget(fields, mock_window_view)
 
     for field in fields:
         if field in ratapi.project.parameter_class_lists:
@@ -236,11 +211,11 @@ def test_project_tab_init():
 
 
 @pytest.mark.parametrize("edit_mode", [True, False])
-def test_project_tab_update_model(classlist, param_classlist, edit_mode):
+def test_project_tab_update_model(classlist, param_classlist, edit_mode, mock_window_view):
     """Test that updating a ProjectTabEditWidget produces the desired models."""
     new_model = {"my_field": classlist, "parameters": param_classlist([])}
 
-    tab = ProjectTabWidget(list(new_model), parent, edit_mode=edit_mode)
+    tab = ProjectTabWidget(list(new_model), mock_window_view, edit_mode=edit_mode)
     # change the parent to a mock to avoid spec issues
     for table in tab.tables.values():
         table.parent = MagicMock()
@@ -260,7 +235,7 @@ def test_project_tab_update_model(classlist, param_classlist, edit_mode):
     ],
 )
 @pytest.mark.parametrize("absorption", [True, False])
-def test_project_tab_validate_layers(input_params, absorption):
+def test_project_tab_validate_layers(input_params, absorption, mock_window_view):
     """Test that the project tab produces the correct result for validating the layers tab."""
     params = ["Param 1", "Param 2", "Invalid Param", ""]
     if absorption:
@@ -300,7 +275,7 @@ def test_project_tab_validate_layers(input_params, absorption):
         ]
     )
 
-    project = ProjectWidget(parent)
+    project = ProjectWidget(mock_window_view)
     project.draft_project = draft
 
     assert list(project.validate_layers()) == expected_err
diff --git a/tests/widgets/project/test_slider_view.py b/tests/widgets/project/test_slider_view.py
index cb7270c3..2aea0ba9 100644
--- a/tests/widgets/project/test_slider_view.py
+++ b/tests/widgets/project/test_slider_view.py
@@ -4,7 +4,6 @@
 import ratapi
 from PyQt6 import QtWidgets
 
-from rascal2.ui.view import MainWindowView
 from rascal2.widgets.project.project import create_draft_project
 from rascal2.widgets.project.slider_view import LabeledSlider, SliderViewWidget
 
@@ -52,22 +51,20 @@ def draft_project():
     return draft
 
 
-def test_no_sliders_creation():
+def test_no_sliders_creation(mock_window_view):
     """Slider view should show warning when there is no fitted parameter."""
-    mw = MainWindowView()
     draft = create_draft_project(ratapi.Project())
     draft["parameters"][0].fit = False
-    slider_view = SliderViewWidget(draft, mw)
+    slider_view = SliderViewWidget(draft, mock_window_view)
     assert len(slider_view.parameters) == 0
     assert len(slider_view._sliders) == 0
     label = slider_view.slider_content_layout.takeAt(0).widget()
     assert label.text().startswith("There are no fitted parameters")
 
 
-def test_sliders_creation(draft_project):
+def test_sliders_creation(draft_project, mock_window_view):
     """Sliders should be created for fitted parameter only."""
-    mw = MainWindowView()
-    slider_view = SliderViewWidget(draft_project, mw)
+    slider_view = SliderViewWidget(draft_project, mock_window_view)
 
     assert len(slider_view.parameters) == 8
     assert len(slider_view._sliders) == 8
@@ -76,30 +73,30 @@ def test_sliders_creation(draft_project):
         assert param_name == slider_name
 
     draft_project["parameters"][0].fit = False
-    slider_view = SliderViewWidget(draft_project, mw)
+    slider_view = SliderViewWidget(draft_project, mock_window_view)
     assert len(slider_view.parameters) == 7
     assert draft_project["parameters"][0].name not in slider_view._sliders
 
 
-def test_accept_and_cancel_slider_buttons():
-    mw = MainWindowView()
+def test_accept_and_cancel_slider_buttons(mock_window_view):
+    mock_window_view.presenter = MagicMock()
     draft = create_draft_project(ratapi.Project())
-    mw.toggle_sliders = MagicMock()
-    mw.plot_widget.update_plots = MagicMock()
-    mw.presenter.edit_project = MagicMock()
+    mock_window_view.toggle_sliders = MagicMock()
+    mock_window_view.plot_widget.update_plots = MagicMock()
+    mock_window_view.presenter.edit_project = MagicMock()
 
-    slider_view = SliderViewWidget(draft, mw)
+    slider_view = SliderViewWidget(draft, mock_window_view)
     buttons = slider_view.findChildren(QtWidgets.QPushButton)
     accept_button = buttons[0]
     accept_button.click()
-    mw.toggle_sliders.assert_called_once()
-    mw.presenter.edit_project.assert_called_once_with(draft)
+    mock_window_view.toggle_sliders.assert_called_once()
+    mock_window_view.presenter.edit_project.assert_called_once_with(draft)
 
-    mw.toggle_sliders.reset_mock()
+    mock_window_view.toggle_sliders.reset_mock()
     cancel_button = buttons[1]
     cancel_button.click()
-    mw.toggle_sliders.assert_called_once()
-    mw.plot_widget.update_plots.assert_called_once()
+    mock_window_view.toggle_sliders.assert_called_once()
+    mock_window_view.plot_widget.update_plots.assert_called_once()
 
 
 @pytest.mark.parametrize(
@@ -110,9 +107,12 @@ def test_accept_and_cancel_slider_buttons():
         ratapi.models.Parameter(name="Param 3", min=3, max=3, value=3, fit=True),
     ],
 )
-@patch("rascal2.widgets.project.slider_view.SliderViewWidget", autospec=True)
-def test_labelled_slider_value(slider_view, param):
-    slider_view.update_result_and_plots = MagicMock()
+@patch("rascal2.widgets.project.slider_view.LOGGER")
+def test_labelled_slider_value(mock_logger, param, mock_window_view):
+    draft = create_draft_project(ratapi.Project())
+    mock_window_view.presenter = MagicMock()
+    slider_view = SliderViewWidget(draft, mock_window_view)
+
     slider = LabeledSlider(param, slider_view)
     # actual range of the slider should never change but
     # value would be scaled to parameter range.
@@ -122,4 +122,9 @@ def test_labelled_slider_value(slider_view, param):
 
     slider._slider.setValue(79)
     assert param.value == slider._slider_value_to_param_value(slider._slider.value())
-    slider_view.update_result_and_plots.assert_called_once()
+    mock_window_view.presenter.quick_run.assert_called_once()
+    mock_window_view.plot_widget.reflectivity_plot.plot.assert_called_once()
+
+    mock_window_view.presenter.quick_run.side_effect = ValueError("calculate error")
+    slider._slider.setValue(90)
+    mock_logger.error.assert_called_once()
diff --git a/tests/widgets/test_inputs.py b/tests/widgets/test_inputs.py
index 6fa7b78d..8143aa5b 100644
--- a/tests/widgets/test_inputs.py
+++ b/tests/widgets/test_inputs.py
@@ -11,8 +11,14 @@
 from pydantic.fields import FieldInfo
 from PyQt6 import QtWidgets
 
-from rascal2.widgets import AdaptiveDoubleSpinBox, MultiSelectComboBox, MultiSelectList, get_validated_input
-from rascal2.widgets.inputs import PathWidget
+from rascal2.widgets import (
+    AdaptiveDoubleSpinBox,
+    MultiSelectComboBox,
+    MultiSelectList,
+    PathWidget,
+    ProgressButton,
+    get_validated_input,
+)
 
 
 class MyEnum(StrEnum):
@@ -86,3 +92,23 @@ def test_path_widget():
     widget.setText(path)
     assert widget.path == path.parent.as_posix()
     assert widget.text() == path.name
+
+
+def test_progress_button():
+    widget = ProgressButton("Progress", "Testing button")
+
+    assert widget.text() == "Progress"
+    widget.default_text = "Start"
+    assert widget.text() == "Start"
+
+    widget.click()
+    assert not widget.isEnabled()
+    assert widget.text() == "Testing button ..."
+
+    widget.update_progress(1, 2)
+    assert not widget.isEnabled()
+    assert widget.text() == "Testing button - 1 of 2"
+
+    widget.hide_progress()
+    assert widget.isEnabled()
+    assert widget.text() == "Start"