### Question:
RefUtils { public static boolean isAnExternalRefFormat(RefFormat refFormat) { return refFormat == RefFormat.URL || refFormat == RefFormat.RELATIVE; } private  RefUtils(); static String computeDefinitionName(String ref); static Optional<String> getExternalPath(String ref); static boolean isAnExternalRefFormat(RefFormat refFormat); static RefFormat computeRefFormat(String ref); static String mungedRef(String refString); static String readExternalUrlRef(String file, RefFormat refFormat, List<AuthorizationValue> auths,
                                            String rootPath); static String readExternalClasspathRef(String file, RefFormat refFormat, List<AuthorizationValue> auths,
                                                  String rootPath); static String buildUrl(String rootPath, String relativePath); static String readExternalRef(String file, RefFormat refFormat, List<AuthorizationValue> auths,
                                         Path parentDirectory);  }### Answer:
@Test public void testIsAnExternalRefFormat() throws Exception { final RefFormat[] values = RefFormat.values(); for (RefFormat value : values) { switch (value) { case URL: case RELATIVE: assertTrue(RefUtils.isAnExternalRefFormat(value)); break; case INTERNAL: assertFalse(RefUtils.isAnExternalRefFormat(value)); break; default: fail("Unhandled RefFormat condition: " + value); } } }