### Question:
StringUtils { public static String decode(String s) { if (isEmpty(s)) { return s; } return url.decode(s); } private  StringUtils(); static String getStringForList(List<? extends Object> objects); static String getStringForList(List<? extends Object> objects, final String delimiter); static String urlEncode(String s); static String urlDecode(String s); static String encode(String s); static String decode(String s); static boolean isEmpty(String value); static boolean nonEmpty(String value); @SuppressWarnings("rawtypes") static boolean isEmpty(Collection collection); @SuppressWarnings("rawtypes") static boolean nonEmpty(Collection collection); static String createDataTypeDisplayName(String dataType); static void setURL(URL u); static final String ALPHA_NUM_REGEXP; static final String ALPHA_NUM_UNDERSCORE_DOT_REGEXP; static final String ALPHA_NUM_SPACE_REGEXP; static final RegExp EXPRESSION; }### Answer:
@Test public void testEmptyDecode() { assertNull(StringUtils.decode(null)); assertSame(EMPTY_STRING, StringUtils.decode(EMPTY_STRING)); verify(url, never()).decode(anyString()); }
@Test public void testDecode() { assertEquals(TEST_STRING, StringUtils.decode(TEST_STRING)); verify(url).decode(TEST_STRING); }