JLDishwasher App

Requirements

Setting min SDK to 9.0 for the sake of the exercise.
Using Carthage as a dependency management tool. I prefer it for building dependencies only once. In real world scenario it may be better to check in sources of dependencies, but I don't for the sake of the exercise.
Instead of default XCTest framework using Quick for BDD style tests. Structure of BDD tests is much cleaner. Together with Nimble for easy and beautiful expectation matching.
Using OHHttpStubs to easily imitate network traffic in unit tests.
Using Argo library for JSON parsing and mapping values to structs. It results in an elegant solutions with immutable objects.
Using Alamofire for networking, which is not really neccesary, but it gives a copule of features for free, i.e. changind urls strings and GET params array into NSURL objects, parsing response to JSON dictionaries. NSURLSession could be also a good choice if depepndencies should be avoided.
Using SDWebImage instead of writing image cache manually.

All properties of structs being mapped from API are optional and if some value is missing the struct is still valid and will be displayed to a user.
If search results response status code is 2xx but content is not a JSON array of products it's a case of empty search results, not an error.
If all prices are in GBP I just interpolate strings and don't mind creating number formatter.

Loading and error view in the grid controller
Default image placeholder in the grid view
Errors deserve more attention. I don't create specific error objects to pass reasons for failure in service
App flow is executed during Unit tests. Delegate should halt this if running tests.