### Question:
LuhnValidator { boolean isValid(String candidate) { throw new UnsupportedOperationException("Delete this statement and write your own implementation."); }    }### Answer:
@Test public void testSingleDigitStringInvalid() { assertFalse(luhnValidator.isValid("1")); }
@Ignore("Remove to run test") @Test public void testSingleZeroIsInvalid() { assertFalse(luhnValidator.isValid("0")); }
@Ignore("Remove to run test") @Test public void testSimpleValidSINReversedRemainsValid() { assertTrue(luhnValidator.isValid("059")); }
@Ignore("Remove to run test") @Test public void testSimpleValidSINReversedBecomesInvalid() { assertTrue(luhnValidator.isValid("59")); }
@Ignore("Remove to run test") @Test public void testValidCanadianSINValid() { assertTrue(luhnValidator.isValid("055 444 285")); }
@Ignore("Remove to run test") @Test public void testInvalidCanadianSINInvalid() { assertFalse(luhnValidator.isValid("055 444 286")); }
@Ignore("Remove to run test") @Test public void testInvalidCreditCardInvalid() { assertFalse(luhnValidator.isValid("8273 1232 7352 0569")); }
@Ignore("Remove to run test") @Test public void testInvalidLongNumberWithAnEvenRemainder() { assertFalse(luhnValidator.isValid("1 2345 6789 1234 5678 9012")); }
@Ignore("Remove to run test") @Test public void testValidNumberWithAnEvenNumberOfDigits() { assertTrue(luhnValidator.isValid("095 245 88")); }
@Ignore("Remove to run test") @Test public void testValidNumberWithAnOddNumberOfSpaces() { assertTrue(luhnValidator.isValid("234 567 891 234")); }
@Ignore("Remove to run test") @Test public void testValidStringsWithANonDigitAtEndInvalid() { assertFalse(luhnValidator.isValid("059a")); }
@Ignore("Remove to run test") @Test public void testStringContainingPunctuationInvalid() { assertFalse(luhnValidator.isValid("055-444-285")); }
@Ignore("Remove to run test") @Test public void testStringContainingSymbolsInvalid() { assertFalse(luhnValidator.isValid("055# 444$ 285")); }
@Ignore("Remove to run test") @Test public void testSingleSpaceWithZeroInvalid() { assertFalse(luhnValidator.isValid(" 0")); }
@Ignore("Remove to run test") @Test public void testMoreThanSingleZeroValid() { assertTrue(luhnValidator.isValid("0000 0")); }
@Ignore("Remove to run test") @Test public void testDigitNineConvertedToOutputNine() { assertTrue(luhnValidator.isValid("091")); }
@Ignore("Remove to run test") @Test public void testUsingASCIIValueForNonDoubledNonDigitNotAllowed() { assertFalse(luhnValidator.isValid("055b 444 285")); }
@Ignore("Remove to run test") @Test public void testUsingASCIIValueForDoubledNonDigitNotAllowed() { assertFalse(luhnValidator.isValid(":9")); }
@Ignore("Remove to run test") @Test public void testStringContainingSymbolsInvalidJavaTrackSpecific() { assertFalse(luhnValidator.isValid("85&")); }