freeCodeCamp/guide/english/certifications/information-security-and-quality-assurance/quality-assurance-and-testing-with-chai/test-if-an-object-is-an-instance-of-a-constructor/index.md

---
title: Test if an Object is an Instance of a Constructor
---
## Test if an Object is an Instance of a Constructor

To begin, locate the file "tests/1_unit_tests.js" and scroll to the suite of tests for 'Objects'.

This file contains multiple suites of tests for the project, and this challenge requires you to make the tests in ``` /** 18 */``` pass.

## Hint 1

The challenge uses objects defined above the tests. Look closely at both, and determine whether the object is an instance of the type being compared against in the assertion.

## Hint 2

Check the error messages to determine if your understanding of the object's instance was correct.

## Hint 3

The lines in the test should be changed from `assert.fail()` to either `assert.instanceOf()` or `assert.notInstanceOf()`.

## Solution

```js
test('#instanceOf, #notInstanceOf', function() {
      
  /** 18 #instanceOf asserts that an object is an instance of a constructor **/
  // Use #instanceOf or #notInstanceOf where appropriate
  assert.notInstanceOf(myCar, Plane);
  assert.instanceOf(airlinePlane, Plane);
  assert.instanceOf(airlinePlane, Object, 'everything is an Object');
  assert.notInstanceOf(myCar.wheels, String );
});
```