@Test
public void testRead_WithEmptyDefaultLanguage() throws Exception {

  // - preparation
  final File file= new File(Resources.getResource("i18n_expected.xlsx").toURI());
  // - execution
  final XlsFile xlsFile= new XlsFile(file);
  // - verification
  final Map<I18nBundleKey, Collection<Translation>> content= xlsFile.getContent();
  assertThat(content).containsOnlyKeys(new I18nBundleKey("i18n/messages", "ok"), new I18nBundleKey("i18n/messages", "cancel"));
  assertThat(content.get(new I18nBundleKey("i18n/messages", "ok"))).containsOnly(
    new Translation(Language.of("de"), "OK"),
    new Translation(Language.of(""), "OK")
  );
  assertThat(content.get(new I18nBundleKey("i18n/messages", "cancel"))).containsOnly(
    new Translation(Language.of("de"), "Abbrechen"),
    new Translation(Language.of(""), "Cancel")
  );
}