const errors = [ { } ]; module.exports = (ruleTester, rule) => ruleTester.run('prefer-string-slice', rule, { valid: [ 'foo.slice()', 'foo.slice(0)', 'foo.slice(1, 2)', 'foo.slice(-3, -2)', ], invalid: [ { code: 'foo.substr()', output: 'foo.slice()', errors, }, { code: '"foo".substr()', output: '"foo".slice()', errors, }, { code: 'foo.substr(start)', errors, }, { code: '"foo".substr(1)', errors, }, { code: 'foo.substr(start, length)', errors, }, { code: '"foo".substr(1, 3)', errors, }, ], });