Решение:
const logRecord = logger.requests[0];
const { statusCode, body } = logRecord.response;
const array = body.toString();
console.log(statusCode);
console.log(JSON.parse(array));
await t
//check if status code is correct
.expect(logger.contains(record => record.response.statusCode === 200)).ok('Status code is NOT correct')
//check if array is not empty
.expect(array.length).gt(0, 'Array is empty!');