Add a basic test for the StepsToReproduce model (#503)

tests/test_stepstoreproduce.py

@@ -0,0 +1,15 @@
+# -*- 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.stepstoreproduce import StepsToReproduceModel
+
+
+def test_get_labels():
+    model = StepsToReproduceModel()
+    classes, _ = model.get_labels()
+    assert classes[1488310]
+    assert not classes[1372243]
+    assert 1319973 not in classes