### Question:
ParamChecker { public static String notEmpty(String s, String paramName) { notNull(s, paramName); if (s.trim().isEmpty()) { throw new IllegalArgumentException(paramName + " cannot be empty"); } return s; }  static T notNull(T t, String paramName); static String notEmpty(String s, String paramName); static List<T> notNulls(List<T> l, String paramName); static int greaterEqualZero(int i, String paramName); static int greaterThan(int i, int base, String paramName); static long greaterEqualZero(long i, String paramName); static long greaterThan(long i, long base, String paramName); static void asserts(boolean b, String msg);  }### Answer:
@Test(expected = IllegalArgumentException.class) public void testNotEmptyFail1() { ParamChecker.notEmpty(null, "s"); }
@Test(expected = IllegalArgumentException.class) public void testNotEmptyFail2() { ParamChecker.notEmpty("", "s"); }
@Test(expected = IllegalArgumentException.class) public void testNotEmptyFail3() { ParamChecker.notEmpty(" ", "s"); }