Function assert

test/testProcess.js:8–17

(value, failMessage, passMessage)

let passed = true;
const assert = function(value, failMessage, passMessage) {
  if (!value) {
    if (failMessage) {
      console.error(failMessage);
    }
    passed = false;
  } else if (passMessage) {
    console.log(passMessage);
  }
};

// assuming file created by testBookOut
wb.xlsx