What frameworks exist to unit test Objective-C code? I would like a framework that integrates nicely with Apple Xcode.
Objective-c – the best way to unit test Objective-C code
cocoaobjective cunit testingxcode
Related Solutions
Look, there's no easy way to do this. I'm working on a project that is inherently multithreaded. Events come in from the operating system and I have to process them concurrently.
The simplest way to deal with testing complex, multithreaded application code is this: If it's too complex to test, you're doing it wrong. If you have a single instance that has multiple threads acting upon it, and you can't test situations where these threads step all over each other, then your design needs to be redone. It's both as simple and as complex as this.
There are many ways to program for multithreading that avoids threads running through instances at the same time. The simplest is to make all your objects immutable. Of course, that's not usually possible. So you have to identify those places in your design where threads interact with the same instance and reduce the number of those places. By doing this, you isolate a few classes where multithreading actually occurs, reducing the overall complexity of testing your system.
But you have to realize that even by doing this, you still can't test every situation where two threads step on each other. To do that, you'd have to run two threads concurrently in the same test, then control exactly what lines they are executing at any given moment. The best you can do is simulate this situation. But this might require you to code specifically for testing, and that's at best a half step towards a true solution.
Probably the best way to test code for threading issues is through static analysis of the code. If your threaded code doesn't follow a finite set of thread safe patterns, then you might have a problem. I believe Code Analysis in VS does contain some knowledge of threading, but probably not much.
Look, as things stand currently (and probably will stand for a good time to come), the best way to test multithreaded apps is to reduce the complexity of threaded code as much as possible. Minimize areas where threads interact, test as best as possible, and use code analysis to identify danger areas.
Compare method
Either you implement a compare-method for your object:
- (NSComparisonResult)compare:(Person *)otherObject {
return [self.birthDate compare:otherObject.birthDate];
}
NSArray *sortedArray = [drinkDetails sortedArrayUsingSelector:@selector(compare:)];
NSSortDescriptor (better)
or usually even better:
NSSortDescriptor *sortDescriptor;
sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"birthDate"
ascending:YES];
NSArray *sortedArray = [drinkDetails sortedArrayUsingDescriptors:@[sortDescriptor]];
You can easily sort by multiple keys by adding more than one to the array. Using custom comparator-methods is possible as well. Have a look at the documentation.
Blocks (shiny!)
There's also the possibility of sorting with a block since Mac OS X 10.6 and iOS 4:
NSArray *sortedArray;
sortedArray = [drinkDetails sortedArrayUsingComparator:^NSComparisonResult(Person *a, Person *b) {
return [a.birthDate compare:b.birthDate];
}];
Performance
The -compare:
and block-based methods will be quite a bit faster, in general, than using NSSortDescriptor
as the latter relies on KVC. The primary advantage of the NSSortDescriptor
method is that it provides a way to define your sort order using data, rather than code, which makes it easy to e.g. set things up so users can sort an NSTableView
by clicking on the header row.
Best Answer
Xcode includes XCTest, which is similar to OCUnit, an Objective-C unit testing framework, and has full support for running XCTest-based unit tests as part of your project's build process. Xcode's unit testing support is described in the Xcode Overview: Using Unit Tests.
Back in the Xcode 2 days, I wrote a series of weblog posts about how to perform some common tasks with Xcode unit testing:
Despite using OCUnit rather than XCTest, the concepts are largely the same.
Finally, I also wrote a few posts on how to write tests for Cocoa user interfaces; the way Cocoa is structured makes it relatively straightforward, because you don't have to spin an event loop or anything like that in most cases.
This makes it possible to do test-driven development for not just your model-level code but also your controller-level and even view-level code.