Asynchronous Mocha测试异步函数，该函数不显式返回承诺

目标功能：

function resolveSteup(resolve, oInitialCreationPromise) {
oInitialCreationPromise ? oInitialCreationPromise.then(() => {
    console.log(
        `create successfully`
    );
}).catch((error) => {
    console.error(
        `Failed to create due to : ${error.message}`
    );
}).finally(resolve) : resolve();

}

resolveSteup函数不显式返回承诺，如何使用mocha进行测试？我们不希望返回带有生产代码的承诺。如何制作下面的测试用例。这个案例有什么最佳实践吗？非常感谢

it('Should resolve finally even initial create project promise rejected', function () {
        let fnResolveStub = sinon.stub();
        resolveSteup(fnResolveStub, Promise.reject());
        expect(fnResolveStub.calledOnce).to.be.true;
       

}))