diff --git a/cura/Settings/CuraStackBuilder.py b/cura/Settings/CuraStackBuilder.py
index d20e686279..a14ae7c328 100644
--- a/cura/Settings/CuraStackBuilder.py
+++ b/cura/Settings/CuraStackBuilder.py
@@ -64,6 +64,7 @@ class CuraStackBuilder:
 
         # Create ExtruderStacks
         extruder_dict = machine_definition.getMetaDataEntry("machine_extruder_trains")
+        print(machine_definition, extruder_dict, machine_definition.getMetaDataEntry)
         for position in extruder_dict:
             cls.createExtruderStackWithDefaultSetup(new_global_stack, position)
 
diff --git a/tests/Settings/TestCuraStackBuilder.py b/tests/Settings/TestCuraStackBuilder.py
new file mode 100644
index 0000000000..9225c617cc
--- /dev/null
+++ b/tests/Settings/TestCuraStackBuilder.py
@@ -0,0 +1,63 @@
+from unittest.mock import patch, MagicMock
+
+import pytest
+
+from UM.Settings.InstanceContainer import InstanceContainer
+from cura.Settings.CuraStackBuilder import CuraStackBuilder
+
+@pytest.fixture
+def global_variant():
+    container = InstanceContainer(container_id="global_variant")
+    container.setMetaDataEntry("type", "variant")
+
+    return container
+
+@pytest.fixture
+def material_instance_container():
+    container = InstanceContainer(container_id="material container")
+    container.setMetaDataEntry("type", "material")
+
+    return container
+
+@pytest.fixture
+def quality_container():
+    container = InstanceContainer(container_id="quality container")
+    container.setMetaDataEntry("type", "quality")
+
+    return container
+
+
+@pytest.fixture
+def quality_changes_container():
+    container = InstanceContainer(container_id="quality changes container")
+    container.setMetaDataEntry("type", "quality_changes")
+
+    return container
+
+
+def test_createMachineWithUnknownDefinition(application, container_registry):
+    application.getContainerRegistry = MagicMock(return_value=container_registry)
+    with patch("cura.CuraApplication.CuraApplication.getInstance", MagicMock(return_value=application)):
+        with patch("UM.ConfigurationErrorMessage.ConfigurationErrorMessage.getInstance") as mocked_config_error:
+            assert CuraStackBuilder.createMachine("Whatever", "NOPE") is None
+            assert mocked_config_error.addFaultyContainers.called_with("NOPE")
+
+
+'''def test_createMachine(application, container_registry, definition_container, global_variant, material_instance_container, quality_container, quality_changes_container):
+    variant_manager = MagicMock(name = "Variant Manager")
+    global_variant_node = MagicMock( name = "global variant node")
+    global_variant_node.getContainer = MagicMock(return_value = global_variant)
+
+    variant_manager.getDefaultVariantNode = MagicMock(return_value = global_variant_node)
+
+    application.getContainerRegistry = MagicMock(return_value=container_registry)
+    application.getVariantManager = MagicMock(return_value = variant_manager)
+    application.empty_material_container = material_instance_container
+    application.empty_quality_container = quality_container
+    application.empty_quality_changes_container = quality_changes_container
+
+    definition_container.getMetaDataEntry = MagicMock(return_value = {}, name = "blarg")
+    print("DEF CONT", definition_container)
+    container_registry.addContainer(definition_container)
+    with patch("cura.CuraApplication.CuraApplication.getInstance", MagicMock(return_value=application)):
+        assert CuraStackBuilder.createMachine("Whatever", "Test Definition") is None'''