diff --git a/tests/TestMachineManager.py b/tests/TestMachineManager.py
index 4f15a0670c..ae681f927d 100644
--- a/tests/TestMachineManager.py
+++ b/tests/TestMachineManager.py
@@ -21,6 +21,7 @@ def machine_manager(application, extruder_manager, container_registry, global_st
     application.getGlobalContainerStack = MagicMock(return_value = global_stack)
     with patch("cura.Settings.CuraContainerRegistry.CuraContainerRegistry.getInstance", MagicMock(return_value=container_registry)):
         manager = MachineManager(application)
+        manager.updateNumberExtrudersEnabled = MagicMock()
         manager._onGlobalContainerChanged()
 
     return manager
@@ -253,4 +254,4 @@ def test_isActiveQualityNotSupported(machine_manager):
 
 def test_isActiveQualityNotSupported_noQualityGroup(machine_manager):
     machine_manager.activeQualityGroup = MagicMock(return_value=None)
-    assert not machine_manager.isActiveQualitySupported
\ No newline at end of file
+    assert not machine_manager.isActiveQualitySupported