Add test to see whether quality profiles deserialise well

Works just the same as the quality-changes stuff.

Contributes to issue CURA-3497.

tests/Settings/TestGlobalStack.py

@@ -80,3 +80,24 @@ def test_deserializeQualityChanges(filename, quality_changes_id, container_regis
     stack.deserialize(serialized)
 
     assert stack.qualityChanges.getId() == quality_changes_id
+
+##  Tests whether the quality profile is being read properly from a global
+#   stack.
+@pytest.mark.parametrize("filename,           quality_id", [
+                        ("Global.global.cfg", "empty"),
+                        ("Global.stack.cfg", "empty"),
+                        ("MachineLegacy.stack.cfg", "empty"),
+                        ("OnlyQuality.global.cfg", "some_instance"),
+                        ("Complete.global.cfg", "some_quality")
+])
+def test_deserializeQualityChanges(filename, quality_id, container_registry):
+    serialized = readStack(filename)
+    stack = cura.Settings.GlobalStack.GlobalStack("TestStack")
+
+    #Mock the loading of the instance containers.
+    stack.findContainer = findSomeContainers
+    UM.Settings.ContainerStack._containerRegistry = container_registry #Always has all the profiles you ask of.
+
+    stack.deserialize(serialized)
+
+    assert stack.quality.getId() == quality_id

tests/Settings/stacks/OnlyQuality.global.cfg

@@ -0,0 +1,8 @@
+[general]
+version = 3
+name = Only Quality
+id = OnlyQuality
+
+[containers]
+2 = some_instance
+6 = some_definition