Mocking PnPContextFactory.CreateAsync() with NSubstitute

[Amwins-Vault-Boy]

I'm trying to mock the CreateAsync() call, but have had no luck. This is what I am trying at the moment:

IPnPContext pnpContextMock = Substitute.For<IPnPContext, IDisposable>();
pnpContextMock.Site.Id.Returns(Guid.NewGuid());

_pnpContextFactoryMock.CreateAsync(Arg.Any<Uri>(), Arg.Any<IAuthenticationProvider>(), Arg.Any<CancellationToken>())
    .ReturnsForAnyArgs(x => Task.FromResult(pnpContextMock));

But won't work, at least like it is right now

Any suggestions?