diff --git a/tests/__init__.py b/tests/__init__.py
new file mode 100644
index 0000000..4721e18
--- /dev/null
+++ b/tests/__init__.py
@@ -0,0 +1 @@
+"""Tests für das Plugin sn_verfahrensgebiet."""
diff --git a/tests/test_dockwidget.py b/tests/test_dockwidget.py
new file mode 100644
index 0000000..da413e9
--- /dev/null
+++ b/tests/test_dockwidget.py
@@ -0,0 +1,86 @@
+import sys
+import types
+import unittest
+from unittest.mock import patch
+
+if "qgis" not in sys.modules:
+    qgis_mod = types.ModuleType("qgis")
+    qgis_utils = types.ModuleType("qgis.utils")
+    qgis_utils.iface = types.SimpleNamespace()
+    qgis_utils.plugins = {}
+    qgis_mod.utils = qgis_utils
+    sys.modules["qgis"] = qgis_mod
+    sys.modules["qgis.utils"] = qgis_utils
+
+from sn_verfahrensgebiet.ui.dockwidget import DockWidget
+
+
+class _DummyTabWidget:
+    def __init__(self):
+        self.tabs = []
+
+    def addTab(self, widget, title):
+        self.tabs.append((widget, title))
+
+
+class _TabWithServices:
+    tab_title = "WithServices"
+
+    def __init__(self, _parent):
+        self.services = None
+
+    def set_services(self, pruefmanager=None, data_grabber=None):
+        self.services = (pruefmanager, data_grabber)
+
+
+class _TabWithoutServices:
+    tab_title = "WithoutServices"
+
+    def __init__(self, _parent):
+        pass
+
+
+class _TabRaises:
+    tab_title = "Broken"
+
+    def __init__(self, _parent):
+        raise RuntimeError("boom")
+
+
+class TestDockWidget(unittest.TestCase):
+
+    @patch("sn_verfahrensgebiet.ui.dockwidget.QTabWidget", _DummyTabWidget)
+    def test_init_tabs_with_services_injects_available_services(self):
+        obj = DockWidget.__new__(DockWidget)
+        obj.tabs = [_TabWithServices, _TabWithoutServices]
+        obj.pruefmanager = object()
+        obj.data_grabber = object()
+        obj._set_widget_calls = []
+        obj.setWidget = lambda value: obj._set_widget_calls.append(value)
+
+        DockWidget._init_tabs_with_services(obj)
+
+        self.assertEqual(len(obj._set_widget_calls), 2)
+        tab_widget = obj._set_widget_calls[-1]
+        self.assertIsInstance(tab_widget, _DummyTabWidget)
+        self.assertEqual(len(tab_widget.tabs), 2)
+
+        first_tab = tab_widget.tabs[0][0]
+        self.assertEqual(first_tab.services, (obj.pruefmanager, obj.data_grabber))
+
+    @patch("sn_verfahrensgebiet.ui.dockwidget.error")
+    @patch("sn_verfahrensgebiet.ui.dockwidget.QTabWidget", _DummyTabWidget)
+    def test_init_tabs_with_services_reports_errors(self, mock_error):
+        obj = DockWidget.__new__(DockWidget)
+        obj.tabs = [_TabRaises]
+        obj.pruefmanager = object()
+        obj.data_grabber = object()
+        obj.setWidget = lambda _value: None
+
+        DockWidget._init_tabs_with_services(obj)
+
+        mock_error.assert_called_once()
+
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/tests/test_main.py b/tests/test_main.py
new file mode 100644
index 0000000..0f029f3
--- /dev/null
+++ b/tests/test_main.py
@@ -0,0 +1,121 @@
+import sys
+import types
+import unittest
+from types import SimpleNamespace
+from unittest.mock import Mock, patch
+
+if "qgis" not in sys.modules:
+    qgis_mod = types.ModuleType("qgis")
+    qgis_utils = types.ModuleType("qgis.utils")
+    qgis_utils.iface = types.SimpleNamespace()
+    qgis_utils.plugins = {}
+    qgis_mod.utils = qgis_utils
+    sys.modules["qgis"] = qgis_mod
+    sys.modules["qgis.utils"] = qgis_utils
+
+from sn_verfahrensgebiet.main import Verfahrensgebiet
+
+
+class _DummyIface:
+    def __init__(self):
+        self.removed = []
+
+    def mainWindow(self):
+        return object()
+
+    def removeDockWidget(self, dock):
+        self.removed.append(dock)
+
+
+class _DummyDock:
+    def __init__(self):
+        self.object_name = None
+        self.action = None
+        self.deleted = False
+
+    def setObjectName(self, name):
+        self.object_name = name
+
+    def deleteLater(self):
+        self.deleted = True
+
+
+class TestPluginMain(unittest.TestCase):
+
+    @patch("sn_verfahrensgebiet.main.DataGrabber")
+    @patch("sn_verfahrensgebiet.main.Pruefmanager")
+    def test_init_sets_services_and_names(self, mock_pruefmanager, mock_data_grabber):
+        pm = object()
+        dg = object()
+        mock_pruefmanager.return_value = pm
+        mock_data_grabber.return_value = dg
+
+        plugin = Verfahrensgebiet(_DummyIface())
+
+        self.assertIs(plugin.pruefmanager, pm)
+        self.assertIs(plugin.data_grabber, dg)
+        self.assertEqual(plugin.plugin_name, "Verfahrensgebiet")
+        self.assertEqual(plugin.dock_name, "sn_dock_verfahrensgebiet")
+
+    @patch("sn_verfahrensgebiet.main.plugins", new_callable=dict)
+    def test_initGui_registers_action_when_basis_ui_exists(self, mock_plugins):
+        iface = _DummyIface()
+        plugin = Verfahrensgebiet(iface)
+
+        ui = SimpleNamespace(
+            add_action=Mock(return_value="action_obj"),
+            finalize_menu_and_toolbar=Mock(),
+        )
+        mock_plugins["sn_basis"] = SimpleNamespace(ui=ui)
+
+        plugin.initGui()
+
+        self.assertEqual(plugin.action, "action_obj")
+        ui.add_action.assert_called_once()
+        ui.finalize_menu_and_toolbar.assert_called_once()
+
+    @patch("sn_verfahrensgebiet.main.plugins", new_callable=dict)
+    @patch("sn_verfahrensgebiet.main.DockManager.show")
+    @patch("sn_verfahrensgebiet.main.DockWidget")
+    def test_run_creates_dock_and_marks_toolbar_active(self, mock_dockwidget_cls, mock_show, mock_plugins):
+        iface = _DummyIface()
+        plugin = Verfahrensgebiet(iface)
+        plugin.action = "action_obj"
+
+        dock = _DummyDock()
+        mock_dockwidget_cls.return_value = dock
+
+        ui = SimpleNamespace(set_active_plugin=Mock())
+        mock_plugins["sn_basis"] = SimpleNamespace(ui=ui)
+
+        plugin.run()
+
+        self.assertIs(plugin.dockwidget, dock)
+        self.assertEqual(dock.object_name, "sn_dock_verfahrensgebiet")
+        self.assertEqual(dock.action, "action_obj")
+        mock_show.assert_called_once_with(dock)
+        ui.set_active_plugin.assert_called_once_with("action_obj")
+
+    @patch("sn_verfahrensgebiet.main.plugins", new_callable=dict)
+    def test_unload_removes_dock_and_action(self, mock_plugins):
+        iface = _DummyIface()
+        plugin = Verfahrensgebiet(iface)
+
+        dock = _DummyDock()
+        plugin.dockwidget = dock
+        plugin.action = "action_obj"
+
+        ui = SimpleNamespace(remove_action=Mock())
+        mock_plugins["sn_basis"] = SimpleNamespace(ui=ui)
+
+        plugin.unload()
+
+        self.assertIn(dock, iface.removed)
+        self.assertTrue(dock.deleted)
+        self.assertIsNone(plugin.dockwidget)
+        ui.remove_action.assert_called_once_with("action_obj")
+        self.assertIsNone(plugin.action)
+
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/tests/test_verfahrensgebiet_alkis.py b/tests/test_verfahrensgebiet_alkis.py
new file mode 100644
index 0000000..46ba82b
--- /dev/null
+++ b/tests/test_verfahrensgebiet_alkis.py
@@ -0,0 +1,184 @@
+import sys
+import types
+import unittest
+from unittest.mock import patch
+
+if "qgis" not in sys.modules:
+    qgis_mod = types.ModuleType("qgis")
+    qgis_utils = types.ModuleType("qgis.utils")
+    qgis_utils.iface = types.SimpleNamespace()
+    qgis_utils.plugins = {}
+    qgis_mod.utils = qgis_utils
+    sys.modules["qgis"] = qgis_mod
+    sys.modules["qgis.utils"] = qgis_utils
+
+from sn_verfahrensgebiet.functions import verfahrensgebiet_alkis as vg
+
+
+class _DummyMessageBox:
+    class StandardButton:
+        Yes = 1
+        No = 2
+
+    last_critical = None
+    next_reply = StandardButton.No
+
+    @staticmethod
+    def question(_parent, _title, _message, _buttons, _default):
+        return _DummyMessageBox.next_reply
+
+    @staticmethod
+    def critical(parent, title, message):
+        _DummyMessageBox.last_critical = (parent, title, message)
+
+
+class _DummyProject:
+    def __init__(self, layers=None):
+        self._layers = layers or []
+        self.removed = []
+
+    def mapLayersByName(self, _name):
+        return self._layers
+
+    def removeMapLayer(self, layer_id):
+        self.removed.append(layer_id)
+
+
+class _DummyExistingLayer:
+    def __init__(self, layer_id="existing"):
+        self._id = layer_id
+
+    def id(self):
+        return self._id
+
+
+class _DummyGeom:
+    def __init__(self, empty=False):
+        self._empty = empty
+
+    def isEmpty(self):
+        return self._empty
+
+
+class _DummyFeature:
+    def __init__(self, geom=None):
+        self._geom = geom or _DummyGeom()
+
+    def geometry(self):
+        return self._geom
+
+
+class _DummyTempLayer:
+    def __init__(self, valid=True, features=None):
+        self._valid = valid
+        self._features = features or []
+
+    def isValid(self):
+        return self._valid
+
+    def getFeatures(self):
+        return self._features
+
+    def crs(self):
+        class _Crs:
+            @staticmethod
+            def authid():
+                return "EPSG:25833"
+
+        return _Crs()
+
+
+class _DummyProvider:
+    def addAttributes(self, _attrs):
+        return True
+
+    def addFeatures(self, _features):
+        return True
+
+
+class _DummyMemoryLayer:
+    def __init__(self):
+        self._provider = _DummyProvider()
+
+    def dataProvider(self):
+        return self._provider
+
+    def updateFields(self):
+        return None
+
+    def updateExtents(self):
+        return None
+
+
+class TestVerfahrensgebietAlkis(unittest.TestCase):
+
+    @patch("sn_verfahrensgebiet.functions.verfahrensgebiet_alkis.QgsProject.instance")
+    @patch("sn_verfahrensgebiet.functions.verfahrensgebiet_alkis.QMessageBox", new=_DummyMessageBox)
+    def test_check_existing_layer_first_load(self, mock_project_instance):
+        mock_project_instance.return_value = _DummyProject(layers=[])
+
+        layer, status = vg._check_existing_layer(tab_widget=None)
+
+        self.assertIsNone(layer)
+        self.assertEqual(status, vg.LoadStatus.FIRST)
+
+    @patch("sn_verfahrensgebiet.functions.verfahrensgebiet_alkis.QgsProject.instance")
+    @patch("sn_verfahrensgebiet.functions.verfahrensgebiet_alkis.QMessageBox", new=_DummyMessageBox)
+    def test_check_existing_layer_keep_existing(self, mock_project_instance):
+        existing = _DummyExistingLayer("L1")
+        mock_project_instance.return_value = _DummyProject(layers=[existing])
+        _DummyMessageBox.next_reply = _DummyMessageBox.StandardButton.No
+
+        layer, status = vg._check_existing_layer(tab_widget=None)
+
+        self.assertIs(layer, existing)
+        self.assertEqual(status, vg.LoadStatus.KEEP)
+
+    @patch("sn_verfahrensgebiet.functions.verfahrensgebiet_alkis.QMessageBox", new=_DummyMessageBox)
+    @patch("sn_verfahrensgebiet.functions.verfahrensgebiet_alkis.get_variable", return_value="")
+    def test_verfahrensgebiet_alkis_fails_when_verfahrensnummer_missing(self, _mock_get_var):
+        _DummyMessageBox.last_critical = None
+
+        layer, status = vg.verfahrensgebiet_alkis(tab_widget=None)
+
+        self.assertIsNone(layer)
+        self.assertEqual(status, vg.LoadStatus.NONE)
+        self.assertIsNotNone(_DummyMessageBox.last_critical)
+
+    @patch("sn_verfahrensgebiet.functions.verfahrensgebiet_alkis._check_existing_layer", return_value=(None, vg.LoadStatus.FIRST))
+    @patch("sn_verfahrensgebiet.functions.verfahrensgebiet_alkis.QMessageBox", new=_DummyMessageBox)
+    @patch("sn_verfahrensgebiet.functions.verfahrensgebiet_alkis.get_variable", return_value="VKZ123")
+    @patch("sn_verfahrensgebiet.functions.verfahrensgebiet_alkis.QgsVectorLayer")
+    def test_verfahrensgebiet_alkis_fails_on_invalid_wfs_layer(self, mock_qgsvectorlayer, _mock_get_var, _mock_check):
+        _DummyMessageBox.last_critical = None
+        mock_qgsvectorlayer.return_value = _DummyTempLayer(valid=False)
+
+        layer, status = vg.verfahrensgebiet_alkis(tab_widget=None)
+
+        self.assertIsNone(layer)
+        self.assertEqual(status, vg.LoadStatus.NONE)
+        self.assertIsNotNone(_DummyMessageBox.last_critical)
+
+    @patch("sn_verfahrensgebiet.functions.verfahrensgebiet_alkis.QgsFeature")
+    @patch("sn_verfahrensgebiet.functions.verfahrensgebiet_alkis.QgsGeometry.unaryUnion", return_value=_DummyGeom(empty=False))
+    @patch("sn_verfahrensgebiet.functions.verfahrensgebiet_alkis._check_existing_layer", return_value=(None, vg.LoadStatus.FIRST))
+    @patch("sn_verfahrensgebiet.functions.verfahrensgebiet_alkis.get_variable", return_value="VKZ123")
+    @patch("sn_verfahrensgebiet.functions.verfahrensgebiet_alkis.QgsVectorLayer")
+    @patch("sn_verfahrensgebiet.functions.verfahrensgebiet_alkis.QMessageBox", new=_DummyMessageBox)
+    def test_verfahrensgebiet_alkis_success_returns_memory_layer(self, mock_qgsvectorlayer, _mock_get_var, _mock_check, _mock_union, mock_feature_cls):
+        temp_layer = _DummyTempLayer(valid=True, features=[_DummyFeature()])
+        memory_layer = _DummyMemoryLayer()
+        mock_qgsvectorlayer.side_effect = [temp_layer, memory_layer]
+
+        mock_feature = mock_feature_cls.return_value
+        mock_feature.setGeometry.return_value = None
+        mock_feature.setAttributes.return_value = None
+
+        layer, status = vg.verfahrensgebiet_alkis(tab_widget=None)
+
+        self.assertIs(layer, memory_layer)
+        self.assertEqual(status, vg.LoadStatus.FIRST)
+
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/tests/test_working_tab.py b/tests/test_working_tab.py
new file mode 100644
index 0000000..683dd27
--- /dev/null
+++ b/tests/test_working_tab.py
@@ -0,0 +1,156 @@
+import sys
+import types
+import unittest
+from unittest.mock import patch
+
+if "qgis" not in sys.modules:
+    qgis_mod = types.ModuleType("qgis")
+    qgis_utils = types.ModuleType("qgis.utils")
+    qgis_utils.iface = types.SimpleNamespace(
+        mapCanvas=lambda: types.SimpleNamespace(setExtent=lambda _e: None, refresh=lambda: None)
+    )
+    qgis_utils.plugins = {}
+    qgis_mod.utils = qgis_utils
+    sys.modules["qgis"] = qgis_mod
+    sys.modules["qgis.utils"] = qgis_utils
+
+from sn_verfahrensgebiet.ui.tabs.working_tab import WorkingTab, LoadStatus
+
+
+class _DummyLayer:
+    def __init__(self, valid=True, layer_id="L1"):
+        self._valid = valid
+        self._id = layer_id
+
+    def isValid(self):
+        return self._valid
+
+    def id(self):
+        return self._id
+
+    def extent(self):
+        return object()
+
+
+class _DummyProject:
+    def __init__(self):
+        self.added = []
+
+    def addMapLayer(self, layer):
+        self.added.append(layer)
+
+
+class _DummyCanvas:
+    def __init__(self):
+        self.extent = None
+
+    def setExtent(self, extent):
+        self.extent = extent
+
+    def refresh(self):
+        return None
+
+
+class _DummyButton:
+    def __init__(self):
+        self._enabled = True
+        self._text = "Aus ALKIS laden"
+
+    def setEnabled(self, enabled):
+        self._enabled = enabled
+
+    def isEnabled(self):
+        return self._enabled
+
+    def setText(self, text):
+        self._text = text
+
+    def text(self):
+        return self._text
+
+
+class _DummyCombo:
+    def __init__(self):
+        self.layer = None
+
+    def setLayer(self, layer):
+        self.layer = layer
+
+
+class TestWorkingTab(unittest.TestCase):
+
+    def _make_tab(self):
+        tab = WorkingTab.__new__(WorkingTab)
+        tab.btn_verf_alkis = _DummyButton()
+        tab.verf_layer_combo = _DummyCombo()
+        tab.haken_verf = object()
+        tab.setze_haken = lambda *_args, **_kwargs: None
+        return tab
+
+    def test_set_busy_updates_button_state(self):
+        tab = self._make_tab()
+
+        tab._set_busy(tab.btn_verf_alkis, True)
+        self.assertFalse(tab.btn_verf_alkis.isEnabled())
+        self.assertEqual(tab.btn_verf_alkis.text(), "Lade ...")
+
+        tab._set_busy(tab.btn_verf_alkis, False)
+        self.assertTrue(tab.btn_verf_alkis.isEnabled())
+        self.assertEqual(tab.btn_verf_alkis.text(), "Aus ALKIS laden")
+
+    @patch("sn_verfahrensgebiet.ui.tabs.working_tab.set_verfahrensgebiet_layer_id")
+    def test_on_verf_layer_changed_valid_sets_variable(self, mock_set_layer_id):
+        tab = self._make_tab()
+        layer = _DummyLayer(valid=True, layer_id="layer_123")
+
+        tab._on_verf_layer_changed(layer)
+
+        mock_set_layer_id.assert_called_once_with("layer_123")
+
+    @patch("sn_verfahrensgebiet.ui.tabs.working_tab.set_verfahrensgebiet_layer_id")
+    def test_on_verf_layer_changed_none_clears_variable(self, mock_set_layer_id):
+        tab = self._make_tab()
+
+        tab._on_verf_layer_changed(None)
+
+        mock_set_layer_id.assert_called_once_with("")
+
+    @patch("sn_verfahrensgebiet.ui.tabs.working_tab.success")
+    @patch("sn_verfahrensgebiet.ui.tabs.working_tab.apply_style")
+    @patch("sn_verfahrensgebiet.ui.tabs.working_tab.QgsProject.instance")
+    @patch("sn_verfahrensgebiet.ui.tabs.working_tab.verfahrensgebiet_alkis")
+    @patch("sn_verfahrensgebiet.ui.tabs.working_tab.iface")
+    @patch("sn_verfahrensgebiet.ui.tabs.working_tab.set_verfahrensgebiet_layer_id")
+    def test_handle_verf_alkis_success_path(
+        self,
+        mock_set_layer_id,
+        mock_iface,
+        mock_alkis,
+        mock_project_instance,
+        mock_apply_style,
+        mock_success,
+    ):
+        tab = self._make_tab()
+        layer = _DummyLayer(valid=True, layer_id="layer_ok")
+        mock_alkis.return_value = (layer, LoadStatus.FIRST)
+        mock_project_instance.return_value = _DummyProject()
+        mock_iface.mapCanvas.return_value = _DummyCanvas()
+
+        tab.handle_verf_alkis()
+
+        mock_apply_style.assert_called_once()
+        mock_success.assert_called_once()
+        mock_set_layer_id.assert_called_with("layer_ok")
+
+    @patch("sn_verfahrensgebiet.ui.tabs.working_tab.set_verfahrensgebiet_layer_id")
+    @patch("sn_verfahrensgebiet.ui.tabs.working_tab.verfahrensgebiet_alkis", return_value=(None, LoadStatus.NONE))
+    def test_handle_verf_alkis_failure_clears_layer_var(self, _mock_alkis, mock_set_layer_id):
+        tab = self._make_tab()
+
+        tab.handle_verf_alkis()
+
+        mock_set_layer_id.assert_called_once_with("")
+
+
+if __name__ == "__main__":
+    unittest.main()