public void appendBrowser() {
final DataBuilder b = new DataBuilder();
final SortedSet<OperatingSystemPattern> osPatternSet = new TreeSet<OperatingSystemPattern>();
final OperatingSystem os = new OperatingSystem(1, "n1", "f1", "iu1", osPatternSet, "p1", "pu1", "u1", "i1");
final BrowserType browserType = new BrowserType(1, "Browser");
final Browser browser = new Browser(4256, UserAgentFamily.FIREBIRD, UserAgentFamily.FIREBIRD.getName(),
new TreeSet<BrowserPattern>(), browserType, os, "icn", "iu1", "p1", "pu1", "u1");
assertThat(b.appendBrowser(browser)).isSameAs(b);
assertThat(b.appendBrowser(browser)).isSameAs(b); // testing to add same, one more time
}