Unit test.

test/test_locked_sched.py

@@ -296,6 +296,21 @@ def test_get_task_id_and_duration_for_project_user_missing(self):
         assert get_task_id_project_id_key(task.id).encode() in sentinel.master.keys()
         assert task.id == task_id
 
+    @with_context
+    @patch('pybossa.core.task_repo.get_task')
+    def get_task_id_and_duration_for_project_user_invalid_task_id(self, get_task):
+        user = UserFactory.create()
+        project = ProjectFactory.create(owner=user, short_name='egil', name='egil',
+                  description='egil')
+        task = TaskFactory.create_batch(1, project=project, n_answers=1)[0]
+        limit = 1
+        timeout = 100
+        acquire_locks(task.id, user.id, limit, timeout)
+        task_id, seconds = get_task_id_and_duration_for_project_user(project.id, user.id)
+
+        assert task_id is None
+        assert seconds == -1
+
     @with_context
     def test_tasks_assigned_as_per_user_access_levels_l1(self):
         """ Test tasks assigned by locked scheduler are as per access levels set for user, task and project"""