static Collection<String> getIssueKeys(ChangeLogSet<?> changelog, Pattern issuePattern) {
        Set<String> issueKeys = new HashSet<>();
        for (ChangeLogSet.Entry entry : changelog) {
            issueKeys.addAll(BlueJiraIssue.findIssueKeys(entry.getMsg(), issuePattern));
        }
        return issueKeys;
    }
@Test
    public void uniqueIssueKeys() throws Exception {
        ChangeLogSet<ChangeLogSet.Entry> entries = build( "TST-123", "TST-123", "TST-123", "TST-124",
                                                          "TST-123", "TST-124", "TST-125");
        Collection<String> keys = JiraSCMListener.getIssueKeys( entries, JiraSite.DEFAULT_ISSUE_PATTERN );
        Assert.assertEquals(3, keys.size());
    }