Add test for gcodeListDecorator

It's super simple, but hey, it's also easy to write.

tests/TestGCodeListDecorator.py

@@ -0,0 +1,16 @@
+from cura.Scene.GCodeListDecorator import GCodeListDecorator
+
+
+def test_setAndGetList():
+    decorator = GCodeListDecorator()
+
+    decorator.setGCodeList(["Test"])
+    assert decorator.getGCodeList() == ["Test"]
+
+
+def test_copyGCodeDecorator():
+    decorator = GCodeListDecorator()
+    decorator.setGCodeList(["Test"])
+    import copy
+    copied_decorator = copy.deepcopy(decorator)
+    assert decorator.getGCodeList() == copied_decorator.getGCodeList()