### Question:
ResourceBundleStringRetriever { public String getMessage(String key, Object... args) { String message = bundle.getString(key); if (args != null && args.length > 0) return MessageFormat.format(message, args); else return message; } ResourceBundleStringRetriever(String bundleName); String getMessage(String key, Object... args); void testAllEntries(MessageLookup[] messageLookups);  }### Answer:
@Test public void testGetMessageEnum() { Assert.assertEquals(TestMessages.SAMPLE_MESSAGE.getMessage(), "hello world!"); }
@Test public void testGetMessageArgEnum() { final String arg = "pop!"; Assert.assertEquals(TestMessages.SAMPLE_ARG_MESSAGE.getMessage(arg), "hello " + arg); }
@Test(expectedExceptions = MissingResourceException.class, expectedExceptionsMessageRegExp = ".*key unknown.*") public void testMissingMessage() { propertyMessages.getMessage("unknown"); }