Add basic test for defect_enhancement_task model (#1019)

Fixes #438

tests/test_defect_enhancement_task.py

@@ -0,0 +1,14 @@
+# -*- coding: utf-8 -*-
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this file,
+# You can obtain one at http://mozilla.org/MPL/2.0/.
+
+from bugbug.models.defect_enhancement_task import DefectEnhancementTaskModel
+
+
+def test_get_defect_enhancement_task_labels():
+    model = DefectEnhancementTaskModel()
+    classes, _ = model.get_labels()
+    assert classes[1042414] == "defect"
+    assert classes[1531080] == "task"
+    assert classes[1348788] == "enhancement"