local valid = require('isbn-verifier').valid describe('isbn-verifier', function() it('valid isbn number', function() assert.is_true(valid('3-598-21508-8')) end) it('invalid isbn check digit', function() assert.is_false(valid('3-598-21508-9')) end) it('valid isbn number with a check digit of 10', function() assert.is_true(valid('3-598-21507-X')) end) it('check digit is a character other than X', function() assert.is_false(valid('3-598-21507-A')) end) it('invalid character in isbn', function() assert.is_false(valid('3-598-2K507-0')) end) it('X is only valid as a check digit', function() assert.is_false(valid('3-598-2X507-9')) end) it('valid isbn without separating dashes', function() assert.is_true(valid('3598215088')) end) it('isbn without separating dashes and X as check digit', function() assert.is_true(valid('359821507X')) end) it('isbn without check digit and dashes', function() assert.is_false(valid('359821507')) end) it('too long isbn and no dashes', function() assert.is_false(valid('3598215078X')) end) it('isbn without check digit', function() assert.is_false(valid('3-598-21507')) end) it('too long isbn', function() assert.is_false(valid('3-598-21507-XX')) end) it('check digit of X should not be used for 0', function() assert.is_false(valid('3-598-21515-X')) end) end)