If I have a class that takes a `org.w3c.dom.History` how can I unit test that class with a fake/mock...

# javascript

[eygraber]

If I have a class that takes a org.w3c.dom.History how can I unit test that class with a fake/mock org.w3c.dom.History?

[turansky]

globalThis.History = MyHistoryMock ?

[eygraber]

How do I mock it? It seems like I can't do anything with it because it is external

public external abstract class History : JsAny

[turansky]

Where declared JsAny ? 🤔

[turansky]

> It seems like I can't do anything with it because it is external
Is it mock method limitation?

[eygraber]

If I do class FakeHistory : org.w3c.dom.History() I get an error that says Non-external type extends external type History

[turansky]

Extending doesn't work - History has no public constructors

[turansky]

Real browser History

[eygraber]

Right, so how am I supposed to unit test without a real one?

[turansky]

globalThis.History = MyHistoryMock

[eygraber]

So it's not possible to unit test outside of the browser?

[Edoardo Luppi]

I've just compiled fine with an extension of History.
Mmm maybe I'm doing something wrong?

[Edoardo Luppi]

Ahhh are you working in the WASM side? JsAny comes from the WASM stdlib.

[Edoardo Luppi]

This seems to be a limitation of the WASM JS target.