Add test to ensure that UM3 and UM3E variants are kept the same

It's a bit chunky, but functional.

tests/TestProfileRequirements.py

@@ -0,0 +1,25 @@
+import configparser #To read the profiles.
+import os #To join paths.
+import pytest
+
+##  Makes sure that the variants for the Ultimaker 3 Extended are exactly the
+#   same as for the Ultimaker 3.
+#
+#   Once we have specialised profiles or a mechanism to inherit variants too, we
+#   may remove this test and have different profiles for the extended where
+#   needed, but until then we should keep them the same. It's happened all too
+#   often that we updated the variants for the UM3 but forgot about the UM3E.
+@pytest.mark.parametrize("um3_file, um3e_file", [
+    #List the corresponding files below.
+    ("ultimaker3_aa0.8.inst.cfg", "ultimaker3_extended_aa0.8.inst.cfg"),
+    ("ultimaker3_aa04.inst.cfg", "ultimaker3_extended_aa04.inst.cfg"),
+    ("ultimaker3_bb0.8.inst.cfg", "ultimaker3_extended_bb0.8.inst.cfg"),
+    ("ultimaker3_bb04.inst.cfg", "ultimaker3_extended_bb04.inst.cfg")
+])
+def test_ultimaker3extended_variants(um3_file, um3e_file):
+    directory = os.path.join(os.path.dirname(__file__), "..", "resources", "variants") #TODO: Hardcoded path relative to this test file.
+    um3 = configparser.ConfigParser()
+    um3.read_file(open(os.path.join(directory, um3_file)))
+    um3e = configparser.ConfigParser()
+    um3e.read_file(open(os.path.join(directory, um3e_file)))
+    assert um3["values"] == um3e["values"]