### Question:
SchemaUpgradeHelper { private String getMinimalUpgradeCatalogVersion(){ List<UpgradeCatalog> candidateCatalogs = new ArrayList<>(allUpgradeCatalogs); Collections.sort(candidateCatalogs, new AbstractUpgradeCatalog.VersionComparator()); if (candidateCatalogs.isEmpty()) { return null; } return candidateCatalogs.iterator().next().getTargetVersion(); } @Inject  SchemaUpgradeHelper(Set<UpgradeCatalog> allUpgradeCatalogs,
                             PersistService persistService,
                             DBAccessor dbAccessor,
                             Configuration configuration); void startPersistenceService(); void stopPersistenceService(); Set<UpgradeCatalog> getAllUpgradeCatalogs(); String readSourceVersion(); void executeUpgrade(List<UpgradeCatalog> upgradeCatalogs); void executePreDMLUpdates(List<UpgradeCatalog> upgradeCatalogs); void executeDMLUpdates(List<UpgradeCatalog> upgradeCatalogs, String ambariUpgradeConfigUpdatesFileName); void executeOnPostUpgrade(List<UpgradeCatalog> upgradeCatalogs); void outputUpgradeJsonOutput(List<UpgradeCatalog> upgradeCatalogs); void resetUIState(); void cleanUpRCATables(); static void main(String[] args);  }### Answer:
@Test public void testGetMinimalUpgradeCatalogVersion() throws Exception{ Method getMinimalUpgradeCatalogVersion = schemaUpgradeHelper.getClass().getDeclaredMethod("getMinimalUpgradeCatalogVersion"); getMinimalUpgradeCatalogVersion.setAccessible(true); String s = (String)getMinimalUpgradeCatalogVersion.invoke(schemaUpgradeHelper); Assert.assertEquals("0.1.0", s); }