Rewire a parent class

[sickOscar]

Hello, I need to rewire a parent class (ES6 syntax) but with the standard way it doesn't seem to work. Using mocha + sinon, here's my situation

Parent class

class Parent {
    save() {
        throw new Error('Unable to save');
    }
}

Child class

class Child extends Parent {
    static aMethod() {
        Child.save()
    }
}

Parent Mock

class parentMock {
    save() {
        throw new Error('mock error');
    }
}

Test

var parentMock = require('./parentMock')
var Child = rewire('./child')

describe("#aMethod", function() {
     before(function() {
         Child.__set__('Parent', parentMock);
    }
    it('should do something', function() {
         try {
            Child.aMethod()
         catch (e) {
            expect(e.message).to.eqls('mock error) // fails with error 'Unable to save'
         }
    }
}

A simple workaround is to stub the save() method with sinon in before function

sinon.stub(Child.prototype, 'save', function() { // this behavior correctly overrides })

but this approach forces me to manually stub the class in tests every time it is extended. Am I missing something? Am I doing something wrong or it is a known issue? Thank you