How I'm testing iPhone apps: part 2
I've recently been doing some iOS development, and working out the best way to test-drive the development of iOS apps was high on my priority list. I know that the automated testing of iOS applications is still not widely practiced and isn't well documented, so I decided to write a series of posts to start to rectify that. You may wish to read part 1 first.
Kiwi
We were looking for a testing framework which supported iOS’s asynchronous programming model and Kiwi answered the call. It has a great syntax, comprehensive set up assistance, asynchronous support and built in mocking. I’d highly recommend you check it out: the syntax helps me to think in the right way and it has pretty much all the features we needed.
Kiwi’s block syntax looks like this:
describe(@"Team", ^{
context(@"when newly created", ^{
it(@"should have a name", ^{
id team = [Team team];
[[team.name should] equal:@"Black Hawks"];
});
});
});Much better than the old fashioned xUnit style of testing, in my opinion. You might hate it, of course. You can use Kiwi’s features without having to use the block syntax if you want.
Objective-C’s delegate model
Many of the Apple core libraries use a delegate pattern for handling callbacks from a class. This is similar to Java’s interfaces, and superficially similar to blocks in Ruby and anonymous functions in Javascript.
As an example, let’s take CoreLocation. When wanting to find the location of a phone, you create a new CoreLocationManager and call startUpdatingLocation on it:
CLLocationManager *manager = [[CLLocationManager alloc] init];
[manager startUpdatingLocation];This call returns immediately: so how do you execute code when the location is found? You use a delegate: an object with responds to the locationManager: didUpdateToLocation: fromLocation method:
-(void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation
{
NSLog("$@ I AM IN YOU", newLocation);
foundLocation = YES;
}Then you set this object to be the CLLocationManager’s delegate before calling startUpdatingLocation. Often you set the delegate to self and define the delegate method on the calling object.
CLLocationManager *manager = [[CLLocationManager alloc] init];
manager.delegate = self;
[manager startUpdatingLocation];There’s more about this model in this article from Apple.
Testing delegates
This is tricky to test, because we can’t simply do this:
it("should call the delegate when ready", ^{
[testObject startUpdatingLocation];
[[testObject.foundLocation should] equal:theValue(YES)];
});The test will call startUpdatingLocation, and then immediately check the foundLocation property to see whether it’s been set. It won’t have been, because the delegate won’t have been called yet.
How were we to stub endpoints such as the location system for for our app? We found two ways of doing this, with varying effectiveness:
- Using Objective-C categories to redefine class methods
- Using a Kiwi stub to inject a derived class which mocks out key methods
Next post, I’ll dive into some detail on both of these methods and show some of the pros and cons of each.
How are you testing iPhone apps? Do chime in throughout the series with suggestions and comments, and I’ll edit the posts as appropriate.
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How to Build a Robust LLM Application
Last month at Cherrypick we launched a brand new meal generator that uses LLMs to create personalized meal plans.
It has been a great success and we are pleased with the results. Customers are changing their plans 30% less and using their plans in their baskets 14% more.
However, getting to this point was not straightforward, and we learned many things that can go wrong when building these types of systems.
Here is what we learned about building an LLM-based product that actually works, and ends up in production rather than languishing in an investor deck as a cool tech demo.
Read moreYour Code Is A Liability
Every chunk of code you commit is more for someone else to read, digest and understand.
Every complex “clever” expression requires another few minutes of effort for each of your team. They must now interpret what you wrote and why you wrote it.
Every line you add limits your project’s responsiveness to change.
Your code is a liability. Never forget this.
Read moreThe Sol Trader Christmas Eve update: moddable missions
The relative radio silence from Sol Trader Towers is for a reason: I’ve been working hard on a flexible and moddable mission structure, that allows players to take a variety of interesting quests in-game.
This build is now available on the forums should you have access (there’s still time if you don’t.)
I’ve built a few missions to start with, including delivering parcels for business or personal reasons, taking characters on business trips and making other characters disappear. It’s great fun to have a variety of things to do for characters now and adds yet more colour to the game. Because it’s completely moddable, I’m also excited to see what storylines other people come up with!
Under the hood
The full details of how to create your own missions are available as a lengthy forum post, which will be kept up to date with changes and clarifications. Here’s an overview:
The missions are organised into packs, which exists under the data/missions subfolder. If you have access to the beta builds, you’ll see there’s one pack there already: these are the missions that are built in to the game.
There are several csv files in each mission folder:
requirements.csv: This file details the cases in which this mission might be triggered. Each character in the game has a chance of picking this mission (and becoming the ‘giver’ of the mission), based on the conditions imposed by this file.conversation_player.csv: The extra conversation options available to the player because of this mission.conversation_ai_response.csv: The extra options the AI can choose from as conversation responses.opinions.csv: The extra opinion triggers, used for reactions to the generation and completion of these missions.strings.csv: The new strings needed for the previous CSV files.
The possibilities for you to build your own missions are expanding all the time, as I add new missions triggers and possible goals for the AI.
What’s next?
At the moment it’s possible to take on any mission from any person, which isn’t very realistic. I need to allow players to gain other character’s trust, so that they will only give you sensitive missions in certain cases. Additionally it will soon be possible to start a career with an organisation, which will give you a rank, a certain amount of built in trust, and access to more senior characters.
I’m also going to be working on the in-space AI very soon. At the moment only freelance traders fly around between planets: it’s time we had passenger ships, military guards and pirates thrown into the mix.
Have a fantastic Christmas and I’ll see you all in the new year with some more updates.
Read moreNew Sol Trader beta: the science of blame and unforgiveness
Previously I wrote about how I’m modelling opinions and prejudice in Sol Trader. It’s time to put some of that information to use.
The opinions a character has of other people, based on the partial events that they know about them, will now directly affect the things that happen in the history generation. This creates new events, which will in turn feed more character opinions.
There’s a new beta available on the forums if you have insider access.
Dudley and Meredith
In the example on the left, we can see that an acrimonious divorce of Meredith’s parents has left an indelible mark on her childhood. She now has a very low opinion of her father, Dudley.
When characters are adults, they can then generate a series of ‘favours’ (or ‘missions’) that they want completed. This is a source of work for the players, although completing certain missions does have real consequences on your relationships with the target of the mission. If they find out you’ve taken a mission against them, then they won’t be happy with you.
To continue our example, Meredith, whom we are now married to, wants us to find out some potentially incriminating information about our own father-in-law, Dudley. It’s up to us whether we take it or not. If he finds out, we’ll make an enemy of him.
As the game goes on, the player will get embroiled in these relationships between the various characters and be able to directly affect their stories. Choosing what to take on and who to ally yourself with forms a major part of Sol Trader’s gameplay.
Sarina’s spiral of doom
Another example: the sad tale of Sarina, our older half sister. I picked Dagny and Warren in history generation to be my character’s parents, knowing that Dagny was cheating on her husband Hayden, mostly to see what happened. Little did I know how much it would affect Sarina, Dagny and Hayden’s eight year old daughter. When she found out about my birth, she got very upset.
She didn’t blame me, thankfully, although she never thought much of me. However, she never really spoke to our mother again, especially since her beloved father Hayden died soon after we were born.
She left home at a young age, and became a political assistant, but she didn’t make too many friends. She was doing ok for a time, only to find out that the love of her life, Richard Ruhr, had been having an affair behind her back all along.
She divorced him, got depressed, quit her job and by the time I grew to adulthood at the start of the game, she was living in a hippie commune somewhere on Mercury, trying desperately to get some gossip on her ex-husband.
New beta out now
This new beta is now available from the forum if you have purchased insider access (if you haven’t there’s still time.) Let me know if you find any other interesting stories such as these!
Read moreModelling opinions and prejudices in Sol Trader
I’ve been working hard on the Sol Trader core gameplay mechanics in the last two weeks. High up on my list was a way of generating more interesting missions for the characters to complete.
In order to have a reason to gather dirt, find locations or desire an early end for an enemy, our characters need to feel strongly about other people they know. This is where their opinions and prejudices come in.
Characters already keep track of the events they know about for each other character in the game. Now they can form an opinion of a character based on the partial set of info they know about someone else’s past.
The plan is to use these thoughts about each other to make decisions about who they’re friends with, deal with relationship breakdown, blame and prejudice.
Here’s an example of how we configure this under the hood for an occasion where a character is caught and reported for taking bribes:
event, opinion, impact, I caught them, I was caught
PRISON_BRIBES, PITIABLE, -0.4, 0, 0
PRISON_BRIBES, MORAL, -0.4, 0, 0
PRISON_BRIBES, INFLUENTIAL, -0.4, 1, 0
PRISON_BRIBES, MY_FRIEND, -1.0, 0, 1Anyone knowing about this event will think the character is less deserving of sympathy and assume the character is less moral. If we’re the one catching them take the bribes, then the briber becomes much less influential over us. If we’re the one being caught, then the one catching us is definitely no longer our friend. Depending on our profession, we will brief against them or possibly try to take them out.
Now characters have opinions about others, we can use these to guide their conversation choices, who they’re likely to target, give us gossip on, etc. It’s all game design fuel for other behaviours in the game, and will combine to form interesting unexpected effects and tell original stories each time.
Next time I’ll discuss about the new events that get created in the history generation because of these new opinions. Our stylised formulaic view of history is about to become, well, a lot more messed up. Rather like real history…
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