def METHOD_NAME(self):
    tracker = Mock(issues_display_url_fmt="http://bugs.example.com/?ids={issue_keys}")
    service = services.IssueTrackerService(tracker)
    url = service.make_issues_display_url([1, 2, 3, 4])
    expected_url = "http://bugs.example.com/?ids=1,2,3,4"
    self.assertEqual(expected_url, url)