td.constructor() breaks instanceof

[eric-parsons]

It seems that starting with version 3.0 of testdouble.js, instanceof checks fail for instances of constructor doubles created via td.constructor():

class Dog { }
var FakeDog = td.constructor(Dog);
var dog = new FakeDog();

console.log(dog instanceof Dog); // true in 2.x, false in 3.x

The same is true for ES5-style constructors, i.e. function Dog() {}. This behaviour is in all 3.x versions up to and including 3.1.1. Unfortunately this is a pretty big breaking change for my code base, preventing me from being able to upgrade.

[searls]

This was intentional because of bugs in how Babel handles type extension causing bugs. Additionally, extending actual types results in real constructors of faked dependencies being invoked, which was never intentional and definitely problematic.

You can get the old behacior by setting the extend constructor option to true:

https://github.com/testdouble/testdouble.js/blob/master/docs/C-configuration.md#tdconfig

[searls]

Your lucky day! By sheer coincidence, the work in #268 just happened to fix this constraint and enabled me to delete that option & restore 2.x's instanceof behavior. I wasn't aiming to fix this but it just happened to sort itself up.

Try 3.2.0 and re-test.

[eric-parsons]

Just tried it with 3.2.0 -- works like a charm. Thanks!