### Question:
IsbnVerifier { boolean isValid(String stringToVerify) { throw new UnsupportedOperationException("Delete this statement and write your own implementation."); }    }### Answer:
@Test public void validIsbnNumber() { assertTrue(isbnVerifier.isValid("3-598-21508-8")); }
@Ignore("Remove to run test") @Test public void invalidIsbnCheckDigit() { assertFalse(isbnVerifier.isValid("3-598-21508-9")); }
@Ignore("Remove to run test") @Test public void validIsbnNumberWithCheckDigitOfTen() { assertTrue(isbnVerifier.isValid("3-598-21507-X")); }
@Ignore("Remove to run test") @Test public void checkDigitIsACharacterOtherThanX() { assertFalse(isbnVerifier.isValid("3-598-21507-A")); }
@Ignore("Remove to run test") @Test public void invalidCharacterInIsbn() { assertFalse(isbnVerifier.isValid("3-598-P1581-X")); }
@Ignore("Remove to run test") @Test public void xIsOnlyValidAsACheckDigit() { assertFalse(isbnVerifier.isValid("3-598-2X507-9")); }
@Ignore("Remove to run test") @Test public void validIsbnWithoutSeparatingDashes() { assertTrue(isbnVerifier.isValid("3598215088")); }
@Ignore("Remove to run test") @Test public void isbnWithoutSeparatingDashesAndXAsCheckDigit() { assertTrue(isbnVerifier.isValid("359821507X")); }
@Ignore("Remove to run test") @Test public void isbnWithoutCheckDigitAndDashes() { assertFalse(isbnVerifier.isValid("359821507")); }
@Ignore("Remove to run test") @Test public void tooLongIsbnAndNoDashes() { assertFalse(isbnVerifier.isValid("3598215078X")); }
@Ignore("Remove to run test") @Test public void tooShortIsbn() { assertFalse(isbnVerifier.isValid("00")); }
@Ignore("Remove to run test") @Test public void isbnWithoutCheckDigit() { assertFalse(isbnVerifier.isValid("3-598-21507")); }
@Ignore("Remove to run test") @Test public void checkDigitOfXShouldNotBeUsedForZero() { assertFalse(isbnVerifier.isValid("3-598-21515-X")); }
@Ignore("Remove to run test") @Test public void emptyIsbn() { assertFalse(isbnVerifier.isValid("")); }
@Ignore("Remove to run test") @Test public void inputIsNineCharacters() { assertFalse(isbnVerifier.isValid("134456729")); }
@Ignore("Remove to run test") @Test public void invalidCharactersAreNotIgnored() { assertFalse(isbnVerifier.isValid("3132P34035")); }
@Ignore("Remove to run test") @Test public void inputIsTooLongButContainsAValidIsbn() { assertFalse(isbnVerifier.isValid("98245726788")); }