Stopping javascript method with super call

Question

I am trying to test an ES6 class method that calls the class method in its parent. For instance:

Polygon.js

class Polygon { verifyDimensions() { this.allSidesValid(); } } export default Polygon; 

Square.js

 import Polygon from './Polygon'; class Square extends Polygon { verifyDimensions() { super.verifyDimensions(); if( this.height !== this.width ) { throw new Error( 'Not square' ); } } } 

I want to check Square proofDimensions without causing polygon checking. Testing with sinon / chai seems like babeljs creates a copy of the original method when creating the class. It is very difficult to drown.

For example, if I configured my test as follows:

Square.spec.js

 beforeEach( () => { sinon.stub( Polygon.prototype, 'verifyDimensions' ); context.verifyDimensions = Square.prototype.verifyDimensions; } ); 

super.verifyDimensions() still refers to Polygon.prototype.verifyDimensions and will be a test error.