Check whether stub getter has been called using sinon

I'm trying to check whether a stubbed getter is being called using sinon.

I've simplified my use case as follows:

export class MyClass {
  public method() {
    return 5;
  }

  public get property() {
    return 5;
  }
}

it("stubs getter", () => {
    const myClass = sinon.createStubInstance(MyClass);
    const stub = sinon.stub(myClass, "property").get(() => 10);
    expect(myClass.property).toBe(10); // passes
    expect(stub.called).toBe(true);    // fails
});

The stubbed getter is clearly working, but I can't seem to be able to verify that it has been called and I can't find anything in the documentation that can help.

Sandbox link

This is because you are stubbing the get accessor but you are spying the property itself. Said differently, the property is never called - hence called being false - but its getter is called.

You should stub the getter and create a spy:

export class MyClass {
  public method() {
    return 5;
  }

  public get property() {
    return 5;
  }
}

it("stubs getter", () => {
    const myClass = sinon.createStubInstance(MyClass);
    sinon.stub(myClass, "property").get(() => 10);

    const spiedGetter = spy(myClass, "property", ["get"]);

    expect(myClass.property).toBe(10); // passes
    expect(spiedGetter.called).toBe(true);    // works
});

The spies documentation of sinon explains this behaviour, although arguably not very well:

https://sinonjs.org/releases/v17/spies/