Add test for ContainerTree

CURA-6600

tests/Machines/TestContainerTree.py

@@ -0,0 +1,52 @@
+from unittest.mock import patch, MagicMock
+import pytest
+from UM.Settings.DefinitionContainer import DefinitionContainer
+from cura.Machines.ContainerTree import ContainerTree
+
+
+def createMockedStack(definition_id: str):
+    result = MagicMock()
+    result.definition.getId = MagicMock(return_value = definition_id)
+    return result
+
+
+@pytest.fixture
+def container_registry():
+    result = MagicMock()
+    result.findContainerStacks = MagicMock(return_value=[createMockedStack("machine_1"), createMockedStack("machine_2")])
+    return result
+
+
+def test_containerTreeInit(container_registry):
+    with patch("UM.Settings.ContainerRegistry.ContainerRegistry.getInstance", MagicMock(return_value=container_registry)):
+        container_tree = ContainerTree()
+
+    assert "machine_1" in container_tree.machines
+    assert "machine_2" in container_tree.machines
+
+
+def test_newMachineAdded(container_registry):
+    mocked_definition_container = MagicMock(spec=DefinitionContainer)
+    mocked_definition_container.getId = MagicMock(return_value = "machine_3")
+
+    with patch("UM.Settings.ContainerRegistry.ContainerRegistry.getInstance", MagicMock(return_value=container_registry)):
+        container_tree = ContainerTree()
+        # machine_3 shouldn't be there, as on init it wasn't in the registry
+        assert "machine_3" not in container_tree.machines
+
+        # But when it does get added (by manually triggering the _machineAdded), it should be there.
+        container_tree._machineAdded(mocked_definition_container)
+        assert "machine_3" in container_tree.machines
+
+
+def test_alreadyKnownMachineAdded(container_registry):
+    mocked_definition_container = MagicMock(spec=DefinitionContainer)
+    mocked_definition_container.getId = MagicMock(return_value="machine_2")
+
+    with patch("UM.Settings.ContainerRegistry.ContainerRegistry.getInstance", MagicMock(return_value=container_registry)):
+        container_tree = ContainerTree()
+        assert len(container_tree.machines) == 2
+
+        # The ID is already there, so no machine should be added.
+        container_tree._machineAdded(mocked_definition_container)
+        assert len(container_tree.machines) == 2