Reactive View Model Refactoring & Testing

[ashfurrow]

No description provided.

[jspahrsummers]

This should be part of the view model's behavior, IMO. You could add a loading property to the VM (informed by didBecomeActiveSignal and photoImage), and then the VC just has to observe that.

[jspahrsummers]

The VMs are kinda light on real presentation logic right now, so the tests aren't super useful, but they're still good to have.

Adding a loading property to the FRPPhotoViewModel (as mentioned above) would open up more interesting testing opportunities, as well as getting into the image loading behaviors of the other VMs.

[ashfurrow]

Thanks for the feedback! I'll have to get on those tonight.

[ashfurrow]

I've updated OCMock to support class method mocks. I need to update the tests, and the book, to reflect that fact.

[jspahrsummers]

It's probably a bit much for your book, but this operation can be written without any state or pesky strongifying:

RAC(self, loading) = [[[RACObserve(self, model)
    sample:self.didBecomeActiveSignal]
    map:^(FRPPhotoModel *model) {
        return [[[[[[FRPPhotoImporter
            fetchPhotoDetails:model]
            catch:^(NSError *error) {
                NSLog(@"Could not fetch photo details: %@", error);
                return [RACSignal empty];
            }]
            doCompleted:^{
                NSLog(@"Fetched photo details.");
            }]
            ignoreValues]
            startWith:@NO]
            concat:[RACSignal return:@YES]];
    }]
    concat];

[ashfurrow]

That's a great idea!