diff --git a/tests/cmd_app/general/__init__.py b/tests/cmd_app/general/__init__.py
new file mode 100644
index 00000000..e69de29b
diff --git a/tests/cmd_app/general/test_project.py b/tests/cmd_app/general/test_project.py
new file mode 100644
index 00000000..6d5cca8a
--- /dev/null
+++ b/tests/cmd_app/general/test_project.py
@@ -0,0 +1,130 @@
+"""
+Unit tests for `geoprob_pipe.cmd_app.general.project.py`.
+Tests performed for:
+    - created_project(app_settings: ApplicationSettings) -> bool
+"""
+
+from unittest.mock import Mock
+
+import pytest
+
+import geoprob_pipe.cmd_app.general.project as module
+
+
+# --- created_project(app_settings: ApplicationSettings) -> bool ---
+@pytest.mark.parametrize(
+    "choice,function_name",
+    [
+        (
+            "Bestaand project openen",
+            "specify_path_to_existing_project",
+        ),
+        (
+            "Nieuw project starten",
+            "specify_dir_for_new_project",
+        ),
+    ],
+)
+def test_created_project_happy_paths(
+    app_settings,
+    monkeypatch,
+    choice: str,
+    function_name: str,
+) -> None:
+    """Test of the paths are correctly completed."""
+    # Arrange
+    # Mock assigned function calls
+    select_mock = Mock()
+    select_mock.return_value.execute.return_value = choice
+
+    monkeypatch.setattr("InquirerPy.inquirer.select", select_mock)
+
+    # Mock called functions
+    action_mock = Mock()
+    monkeypatch.setattr(
+        module,
+        function_name,
+        action_mock,
+    )
+    logging_mock = Mock()
+    monkeypatch.setattr(
+        module,
+        "enable_geopackage_logging",
+        logging_mock,
+    )
+
+    # Act
+    result: bool = module.created_project(app_settings)
+
+    # Assert
+    # Check path reaches return
+    assert result is True
+
+    # Check functions were called once with correct arguments
+    action_mock.assert_called_once_with(app_settings)
+
+    logging_mock.assert_called_once_with(app_settings=app_settings)
+
+
+def test_created_project_compare(monkeypatch) -> None:
+    """Test start compare function."""
+    # Arrange
+    # Mock assigned function calls
+    prompt_mock = Mock()
+    choice: str = "Twee projectbestanden vergelijken"
+    prompt_mock.execute.return_value = choice
+    monkeypatch.setattr("InquirerPy.inquirer.select", Mock(return_value=prompt_mock))
+
+    # Mock called functions
+    compare_mock = Mock()
+    monkeypatch.setattr(module, "start_comparison", compare_mock)
+
+    # Act
+    # While capturing the sysexit() run the function
+    with pytest.raises(SystemExit, match="Applicatie afgesloten"):
+        module.created_project(Mock())
+
+    # Assert
+    # Check function call
+    compare_mock.assert_called_once()
+
+
+def test_created_project_single_calc(monkeypatch) -> None:
+    # Arrange
+    # Mock assigned function calls
+    prompt_mock = Mock()
+    choice: str = "Inspecteer een enkele berekening"
+    prompt_mock.execute.return_value = choice
+    monkeypatch.setattr("InquirerPy.inquirer.select", Mock(return_value=prompt_mock))
+
+    # Mock called functions
+    panel_instance = Mock()
+    panel_mock = Mock(return_value=panel_instance)
+    monkeypatch.setattr(
+        module,
+        "Panel",
+        panel_mock,
+    )
+    console_instance = Mock()
+    console_mock = Mock(return_value=console_instance)
+    monkeypatch.setattr(
+        module,
+        "Console",
+        console_mock,
+    )
+    # Act
+    # While capturing the sysexit() run the function
+    with pytest.raises(SystemExit, match="Applicatie afgesloten"):
+        module.created_project(Mock())
+
+    # Assert
+    # Check Panel construction
+    panel_mock.assert_called_once_with(
+        module.EXPLANATION_REPRODUCING_SINGLE_CALCULATION,
+        title="INSPECTEER EEN ENKELE BEREKENING",
+        title_align="left",
+        border_style="bright_blue",
+        padding=(0, 2),
+    )
+    # Check print call
+    console_instance.print.assert_called_once_with(panel_instance)
diff --git a/tests/cmd_app/general/test_traject_parameters.py b/tests/cmd_app/general/test_traject_parameters.py
new file mode 100644
index 00000000..45bbac99
--- /dev/null
+++ b/tests/cmd_app/general/test_traject_parameters.py
@@ -0,0 +1,122 @@
+"""
+Unit tests for `geoprob_pipe.cmd_app.general.traject_parameters.py`.
+Tests performed for:
+    - _specify_w(app_settings: ApplicationSettings)
+"""
+
+from unittest.mock import Mock
+
+import pytest
+
+import geoprob_pipe.cmd_app.general.traject_parameters as module
+
+
+# --- _specify_w(app_settings: ApplicationSettings) ---
+@pytest.mark.parametrize(
+    "input_value, expected_answer",
+    [
+        ("", "geen w gespecificeerd"),
+        ("abc", "geen decimaal getal"),
+        ("1.5", "groter dan 1.0"),
+        ("0", "kleiner of gelijk aan 0.0"),
+        ("-1", "kleiner of gelijk aan 0.0"),
+    ],
+)
+def test_specify_w_validations(
+    app_settings,
+    monkeypatch,
+    capsys,
+    input_value: str,
+    expected_answer: str,
+) -> None:
+    """Test for all branches of validation and correct storage of user input."""
+    # Arrange
+    # Setup user inputs
+    user_inputs = iter([input_value, "0.24"])
+
+    # Mock assigned function calls
+    prompt_mock = Mock()
+    prompt_mock.execute.side_effect = lambda: next(user_inputs)
+
+    monkeypatch.setattr(
+        "InquirerPy.inquirer.text",
+        Mock(return_value=prompt_mock),
+    )
+
+    # Mock called functions
+    append_mock = Mock()
+    monkeypatch.setattr(
+        module,
+        "_append_to_db",
+        append_mock,
+    )
+
+    # Act
+    # Run tested function:
+    module._specify_w(app_settings)
+
+    # Assert
+    # Check correct message printed
+    captured = capsys.readouterr()
+    assert expected_answer in captured.out
+
+    # Check continue loop
+    assert prompt_mock.execute.call_count == 2
+
+    # Check accepted value stored correctly
+    append_mock.assert_called_once_with(
+        app_settings=app_settings,
+        key="w",
+        value=0.24,  # as a float
+    )
+
+
+@pytest.mark.parametrize("input_value", ["0.01", "1.0"])
+def test_specify_w_valid_boundaries(app_settings, monkeypatch, input_value: str) -> None:
+    """Test that the valid boundaries are accepted."""
+    # Arrange
+    prompt_mock = Mock()
+    prompt_mock.execute.return_value = input_value
+    monkeypatch.setattr(
+        "InquirerPy.inquirer.text",
+        Mock(return_value=prompt_mock),
+    )
+
+    append_mock = Mock()
+    monkeypatch.setattr(module, "_append_to_db", append_mock)
+
+    # Act
+    module._specify_w(app_settings)
+
+    # Assert
+    prompt_mock.execute.assert_called_once()
+    append_mock.assert_called_once_with(
+        app_settings=app_settings,
+        key="w",
+        value=float(input_value),
+    )
+
+
+def test_specify_w_strips_surrounding_spaces(app_settings, monkeypatch) -> None:
+    """Test that surrounding spaces are removed before validation."""
+    # Arrange
+    prompt_mock = Mock()
+    prompt_mock.execute.return_value = " 0.24 "
+    monkeypatch.setattr(
+        "InquirerPy.inquirer.text",
+        Mock(return_value=prompt_mock),
+    )
+
+    append_mock = Mock()
+    monkeypatch.setattr(module, "_append_to_db", append_mock)
+
+    # Act
+    module._specify_w(app_settings)
+
+    # Assert
+    prompt_mock.execute.assert_called_once()
+    append_mock.assert_called_once_with(
+        app_settings=app_settings,
+        key="w",
+        value=0.24,
+    )
diff --git a/tests/cmd_app/spatial_layers/test_binnenteenlijn.py b/tests/cmd_app/spatial_layers/test_binnenteenlijn.py
new file mode 100644
index 00000000..63344032
--- /dev/null
+++ b/tests/cmd_app/spatial_layers/test_binnenteenlijn.py
@@ -0,0 +1,92 @@
+"""
+Unit tests for `geoprob_pipe.cmd_app.spatial_layers.binnenteenlijn.py`.
+Tests performed for:
+    - added_binnenteenlijn(app_settings: ApplicationSettings) -> bool
+"""
+
+from unittest.mock import Mock
+
+import geoprob_pipe.cmd_app.spatial_layers.binnenteenlijn as module
+
+
+# --- added_binnenteenlijn(app_settings: ApplicationSettings) -> bool ---
+def test_added_binnenteenlijn_already_included(
+    app_settings,
+    monkeypatch,
+    capsys,
+) -> None:
+    """Test case `binnenteenlijn` already added to gpkg."""
+    # Arrange
+    # Monkey patch assigned function calls
+    monkeypatch.setattr(
+        module.fiona,
+        "listlayers",
+        Mock(
+            return_value=[
+                "trajectlijn",
+                "binnenteenlijn",
+                "vakindeling",
+            ]
+        ),
+    )
+
+    # Mock called module fuctions
+    request_mock = Mock()
+    monkeypatch.setattr(
+        module,
+        "request_binnenteenlijn_filepath",
+        request_mock,
+    )
+
+    # Act
+    # Run tested function:
+    result: bool = module.added_binnenteenlijn(app_settings)
+
+    # Assert
+    # Check expected return
+    assert result is True
+
+    # Check correct message printed
+    captured = capsys.readouterr()
+    assert "Binnenteenlijn al toegevoegd" in captured.out
+
+    # Check function in other branch not called
+    request_mock.assert_not_called()
+
+
+def test_added_binnenteenlijn_not_yet_included(
+    app_settings,
+    monkeypatch,
+) -> None:
+    """Test case `binnenteenlijn` not yet added to gpkg."""
+    # Arrange
+    # Monkey patch assigned function call(s)
+    monkeypatch.setattr(
+        module.fiona,
+        "listlayers",
+        Mock(
+            return_value=[
+                "trajectlijn",
+                "vakindeling",
+            ]
+        ),
+    )
+
+    # Mock called module fuction(s)
+    request_mock = Mock()
+    monkeypatch.setattr(
+        module,
+        "request_binnenteenlijn_filepath",
+        request_mock,
+    )
+
+    # Act
+    # Run tested function:
+    result: bool = module.added_binnenteenlijn(app_settings)
+
+    # Assert
+    # Check expected return
+    assert result is True
+
+    # Check function call with correct argument
+    request_mock.assert_called_once_with(app_settings=app_settings)
diff --git a/tests/conftest.py b/tests/conftest.py
new file mode 100644
index 00000000..37970c6b
--- /dev/null
+++ b/tests/conftest.py
@@ -0,0 +1,13 @@
+import pytest
+
+from geoprob_pipe.cmd_app.cmd import ApplicationSettings
+
+
+@pytest.fixture
+def app_settings(tmp_path) -> ApplicationSettings:
+    settings = ApplicationSettings()
+    
+    settings.workspace_dir = str(tmp_path)
+    settings.geopackage_filename = "dummy.gpkg"
+    
+    return settings
\ No newline at end of file
diff --git a/tests/results/__init__.py b/tests/results/__init__.py
new file mode 100644
index 00000000..e69de29b
diff --git a/tests/results/assemblage/__init__.py b/tests/results/assemblage/__init__.py
new file mode 100644
index 00000000..e69de29b
diff --git a/tests/results/assemblage/test_assemblage.py b/tests/results/assemblage/test_assemblage.py
deleted file mode 100644
index 976378b1..00000000
--- a/tests/results/assemblage/test_assemblage.py
+++ /dev/null
@@ -1,59 +0,0 @@
-from geoprob_pipe.results.assemblage.functions import combine_series
-from geoprob_pipe.results.assemblage.functions import window_collect
-from geoprob_pipe.results.assemblage.functions import scaled_collect
-from geoprob_pipe.results.assemblage.objects import UittredepuntElement
-import pytest
-
-
-def test_combine():
-    """Test combining very small floats.
-    """
-    pfs = [1.123e-17, 3.78e-15, 6.7e-15]
-    sum_pf, max_pf = combine_series(pfs)
-    assert sum_pf == pytest.approx(1.049123e-14)
-    assert max_pf == pytest.approx(6.7e-15)
-
-
-def test_window():
-    """Test window on selecting max in window and combining.
-    """
-    list_dsn = [
-        UittredepuntElement(m_value=11, a=0.9, converged=True, pf=1e-12,
-                            flow_chart_number=11, advise="-"),
-        UittredepuntElement(m_value=12, a=0.9, converged=True, pf=2e-13,
-                            flow_chart_number=11, advise="-"),
-        UittredepuntElement(m_value=20, a=0.9, converged=True, pf=7.5e-13,
-                            flow_chart_number=11, advise="-"),
-        UittredepuntElement(m_value=30, a=0.9, converged=True, pf=3e-14,
-                            flow_chart_number=11, advise="-")
-    ]
-    sum_pf, max_pf, elements = window_collect(
-        window_size=10, point_list=list_dsn,
-        m_van=0, m_tot=40
-        )
-    assert sum_pf == pytest.approx(1.78e-12)
-    assert max_pf == pytest.approx(1e-12)
-    assert elements.__len__() == 4
-    assert elements[0].kans_dsn.pf == 0.0
-
-
-def test_scaled():
-    """Test scaled on taking max in cluster and combining.
-    """
-    list_dsn = [
-        UittredepuntElement(m_value=11, a=0.9, converged=True, pf=1e-12,
-                            flow_chart_number=11, advise="-"),
-        UittredepuntElement(m_value=12, a=0.9, converged=True, pf=2e-13,
-                            flow_chart_number=11, advise="-"),
-        UittredepuntElement(m_value=20, a=0.9, converged=True, pf=7.5e-13,
-                            flow_chart_number=11, advise="-"),
-        UittredepuntElement(m_value=30, a=0.9, converged=True, pf=3e-14,
-                            flow_chart_number=11, advise="-")
-    ]
-    sum_pf, max_pf, elements = scaled_collect(
-        dL=200, point_list=list_dsn,
-        m_van=0, m_tot=50
-        )
-    assert sum_pf == pytest.approx(1.78e-12)
-    assert max_pf == pytest.approx(1e-12)
-    assert elements.__len__() == 3
diff --git a/tests/results/assemblage/test_functions_assemblage.py b/tests/results/assemblage/test_functions_assemblage.py
new file mode 100644
index 00000000..20f347b3
--- /dev/null
+++ b/tests/results/assemblage/test_functions_assemblage.py
@@ -0,0 +1,197 @@
+"""
+Unit tests for `assemblage.functions` and `assemblage.objects` in `geoprob_pipe.results.assemblage.functions`.
+"""
+
+import pytest
+
+import geoprob_pipe.results.assemblage.functions as functions
+import geoprob_pipe.results.assemblage.objects as objects
+
+
+@pytest.fixture
+def uittredepunten() -> list[objects.UittredepuntElement]:
+    return [
+        objects.UittredepuntElement(
+            m_value=11,
+            a=0.9,
+            converged=True,
+            pf=1e-12,
+            flow_chart_number=11,
+            advise="-",
+        ),
+        objects.UittredepuntElement(
+            m_value=12,
+            a=0.9,
+            converged=True,
+            pf=2e-13,
+            flow_chart_number=11,
+            advise="-",
+        ),
+        objects.UittredepuntElement(
+            m_value=20,
+            a=0.9,
+            converged=True,
+            pf=7.5e-13,
+            flow_chart_number=11,
+            advise="-",
+        ),
+        objects.UittredepuntElement(
+            m_value=30,
+            a=0.9,
+            converged=True,
+            pf=3e-14,
+            flow_chart_number=11,
+            advise="-",
+        ),
+    ]
+
+
+def test_combine_series_with_small_probabilities() -> None:
+    """Check addition of very small probabilities"""
+
+    # Arrange
+    pfs: list[float] = [1.123e-17, 3.78e-15, 6.7e-15]
+
+    # Act
+    sum_pf: float
+    max_pf: float
+    sum_pf, max_pf = functions.combine_series(pfs)
+
+    # Assert
+    assert sum_pf == pytest.approx(1.049123e-14)
+    assert max_pf == pytest.approx(6.7e-15)
+
+
+def test_combine_series_empty_list() -> None:
+    """Assert correct return on input of empty list."""
+    # Arrange
+    pfs: list[float] = []
+
+    # Act
+    sum_pf: float
+    max_pf: float
+    sum_pf, max_pf = functions.combine_series(pfs)
+
+    # Assert
+    assert sum_pf == 0.0
+    assert max_pf == 0.0
+
+
+@pytest.mark.parametrize(
+    "L, a, dL, expected",
+    [
+        (100.0, 0.5, 20.0, 2.5),  # larger than 1
+        (10.0, 0.5, 20.0, 1.0),  # minimum = 1
+        (20.0, 1.0, 20.0, 1.0),  # exact 1
+        (200.0, 0.8, 40.0, 4.0),  # normal case
+    ],
+)
+def test_bepaal_N_vak(L: float, a: float, dL: float, expected: float) -> None:
+    """Controleer correcte calculation of N_vak."""
+    result = functions.bepaal_N_vak(L=L, a=a, dL=dL)
+
+    assert result == pytest.approx(expected)
+
+
+@pytest.mark.parametrize(
+    "a",
+    [-0.1, -1.0, -100.0],
+)
+def test_bepaal_N_vak_raises_for_negative_a(a: float) -> None:
+    """Assert that a negative value of a raise a ValueError"""
+    with pytest.raises(ValueError, match="a moet groter zijn dan 0"):
+        functions.bepaal_N_vak(L=100.0, a=a, dL=20.0)
+
+
+@pytest.mark.parametrize(
+    "L, dL",
+    [
+        (-1.0, 20.0),
+        (100.0, -20.0),
+        (-1.0, -20.0),
+    ],
+)
+def test_bepaal_N_vak_raises_for_negative_lengths(L: float, dL: float) -> None:
+    """Assert that negative values for L and dL raise a ValueError."""
+    with pytest.raises(
+        ValueError,
+        match="De lengte L en dL moeten groter zijn dan 0",
+    ):
+        functions.bepaal_N_vak(L=L, a=0.5, dL=dL)
+
+
+def test_window_collect_returns_expected_values(uittredepunten) -> None:
+    """Check selection inside windows and combined probability."""
+
+    # Act
+    sum_pf: float
+    max_pf: float
+    elements: list[objects.WindowElement]
+    sum_pf, max_pf, elements = functions.window_collect(
+        window_size=10,
+        point_list=uittredepunten,
+        m_van=0,
+        m_tot=40,
+    )
+
+    # Assert
+    assert sum_pf == pytest.approx(1.78e-12)
+    assert max_pf == pytest.approx(1e-12)
+    assert len(elements) == 4
+    assert elements[0].kans_dsn.pf == pytest.approx(0.0)
+
+
+def test_window_collect_empty_list() -> None:
+    # Act
+    sum_pf: float
+    max_pf: float
+    elements: list[objects.WindowElement]
+    sum_pf, max_pf, elements = functions.window_collect(
+        window_size=10,
+        point_list=[],
+        m_van=0,
+        m_tot=50,
+    )
+
+    # Assert
+    assert sum_pf == 0.0
+    assert max_pf == 0.0
+    assert len(elements) == 0
+
+
+def test_scaled_collect_returns_expected_values(uittredepunten) -> None:
+    """Check clustering, scale factor en combined probability."""
+
+    # Act
+    sum_pf: float
+    max_pf: float
+    elements: list[objects.WindowElement]
+    sum_pf, max_pf, elements = functions.scaled_collect(
+        dL=200,
+        point_list=uittredepunten,
+        m_van=0,
+        m_tot=50,
+    )
+
+    # Assert
+    assert sum_pf == pytest.approx(1.78e-12)
+    assert max_pf == pytest.approx(1e-12)
+    assert len(elements) == 3
+
+
+def test_scaled_collect_empty_list() -> None:
+    # Act
+    sum_pf: float
+    max_pf: float
+    elements: list[objects.WindowElement]
+    sum_pf, max_pf, elements = functions.scaled_collect(
+        dL=200,
+        point_list=[],
+        m_van=0,
+        m_tot=50,
+    )
+
+    # Assert
+    assert sum_pf == 0.0
+    assert max_pf == 0.0
+    assert len(elements) == 0
\ No newline at end of file