Add tests for deserialising a stack with user changes

Code is mostly copied over from the global stack, which should work in a similar way.

Contributes to issue CURA-3497.

tests/Settings/TestExtruderStack.py

@@ -1,16 +1,52 @@
 # Copyright (c) 2017 Ultimaker B.V.
 # Cura is released under the terms of the AGPLv3 or higher.
 
+import os.path #To find the test stack files.
 import pytest #This module contains automated tests.
 import unittest.mock #For the mocking and monkeypatching functionality.
 
+import UM.Settings.ContainerRegistry #To create empty instance containers.
+import UM.Settings.ContainerStack #To set the container registry the container stacks use.
+from UM.Settings.DefinitionContainer import DefinitionContainer #To check against the class of DefinitionContainer.
 import cura.Settings.ExtruderStack #The module we're testing.
 from cura.Settings.Exceptions import InvalidOperationError #To check whether the correct exceptions are raised.
 
+##  Fake container registry that always provides all containers you ask of.
+@pytest.fixture()
+def container_registry():
+    registry = unittest.mock.MagicMock()
+    def findContainers(id = None):
+        if not id:
+            return [UM.Settings.ContainerRegistry._EmptyInstanceContainer("test_container")]
+        else:
+            return [UM.Settings.ContainerRegistry._EmptyInstanceContainer(id)]
+    registry.findContainers = findContainers
+    return registry
+
 ##  An empty extruder stack to test with.
 @pytest.fixture()
 def extruder_stack() -> cura.Settings.ExtruderStack.ExtruderStack:
-    return cura.Settings.ExtruderStack.ExtruderStack
+    return cura.Settings.ExtruderStack.ExtruderStack("TestStack")
+
+##  Place-in function for findContainer that finds only containers that start
+#   with "some_".
+def findSomeContainers(container_id = "*", container_type = None, type = None, category = "*"):
+    if container_id.startswith("some_"):
+        return UM.Settings.ContainerRegistry._EmptyInstanceContainer(container_id)
+    if container_type == DefinitionContainer:
+        definition_mock = unittest.mock.MagicMock()
+        definition_mock.getId = unittest.mock.MagicMock(return_value = "some_definition") #getId returns some_definition.
+        return definition_mock
+
+##  Helper function to read the contents of a container stack in the test
+#   stack folder.
+#
+#   \param filename The name of the file in the "stacks" folder to read from.
+#   \return The contents of that file.
+def readStack(filename):
+    with open(os.path.join(os.path.dirname(os.path.abspath(__file__)), "stacks", filename)) as file_handle:
+        serialized = file_handle.read()
+    return serialized
 
 #############################START OF TEST CASES################################
 
@@ -19,6 +55,26 @@ def test_addContainer(extruder_stack):
     with pytest.raises(InvalidOperationError):
         extruder_stack.addContainer(unittest.mock.MagicMock())
 
+@pytest.mark.parametrize("filename, user_changes_id", [
+    ("Left.extruder.cfg", "empty"),
+    ("ExtruderLegacy.stack.cfg", "empty"),
+    ("OnlyUser.extruder.cfg", "some_instance"),
+    ("Complete.extruder.cfg", "some_user_changes")
+])
+def test_deserializeUserChanges(filename, user_changes_id, container_registry, extruder_stack):
+    serialized = readStack(filename)
+
+    #Mock the loading of the instance containers.
+    extruder_stack.findContainer = findSomeContainers
+    original_container_registry = UM.Settings.ContainerStack._containerRegistry
+    UM.Settings.ContainerStack._containerRegistry = container_registry #Always has all profiles you ask of.
+
+    extruder_stack.deserialize(serialized)
+    assert extruder_stack.userChanges.getId() == user_changes_id
+
+    #Restore.
+    UM.Settings.ContainerStack._containerRegistry = original_container_registry
+
 ##  Tests whether inserting a container is properly forbidden.
 def test_insertContainer(extruder_stack):
     with pytest.raises(InvalidOperationError):

tests/Settings/stacks/Complete.extruder.cfg

@@ -0,0 +1,13 @@
+[general]
+version = 3
+name = Complete
+id = Complete
+
+[containers]
+0 = some_user_changes
+1 = some_quality_changes
+2 = some_quality
+3 = some_material
+4 = some_variant
+5 = some_definition_changes
+6 = some_definition

tests/Settings/stacks/OnlyUser.extruder.cfg

@@ -0,0 +1,8 @@
+[general]
+version = 3
+name = Only User
+id = OnlyUser
+
+[containers]
+0 = some_instance
+6 = some_definition