### Question:
IntegerValidator { private IntegerValidator() { } private  IntegerValidator(); static boolean isParseable(String input); static Integer tryParse(String input);  }### Answer:
@Test public void testIntegerValidator() { new Random().ints(25).forEach(i -> { assertTrue(IntegerValidator.isParseable(String.valueOf(i))); assertEquals(Integer.valueOf(i), IntegerValidator.tryParse(String.valueOf(i))); }); for (String testValue : new String[]{"test", "true", System.getProperty("user.dir")}) { assertFalse(IntegerValidator.isParseable(testValue)); assertNull(IntegerValidator.tryParse(testValue)); } }