Problem using MockingJay about mockingjay

[kylef]

I've made some changes in Mockingjay 1.2.1 which now swizzles NSURLSessionConfiguration on load of Mockingjay.

This fixes problems when you create a session and then register a stub before we've added the Mockingjay protocol to NSURLSessionConfiguration.

If anyone is still having any problems with Mockingjay after 1.2.1, please file a new issue with steps to reproduce the problem and I'll take a look.

Thanks all!

[paulyoung]

I'm seeing a similar thing with Xcode 7.2 and Swift 2.1.1 using the same technique as a different project that is known to work with Xcode 7.0 and Swift 2.0

I'll try to provide more details.

[paulyoung]

From what I can tell, differences in Xcode / Swift versions have no relevance to my issue.

I've tried stepping through in the debugger but my matcher is never called.

This is the relevant spec and test failure.

[paulyoung]

@kylef any tips on how to debug this?

[paulyoung]

I little bit more info – my APIClient accepts a configuration argument, so I created a configuration the same as the one that Mockingly swizzles with and passed that in:

let configuration = NSURLSessionConfiguration.defaultSessionConfiguration()
configuration.protocolClasses = [MockingjayProtocol.self] as [AnyClass] + configuration.protocolClasses!

let token = "token"
let client = APIClient(token: token, configuration: configuration)

This produced the same test failure.

[paulyoung]

After setting a breakpoint in canInitWithRequest: on MockingjayProtocol I'm able to step through and see that my matcher is called.

This now looks like an error on my part. Why I wasn't able to step through or pause execution on those breakpoints before, I'm not sure.

[paulyoung]

I fixed the issue on my side and the test passed, so I removed the manually passed configuration and can confirm that canInitWithRequest: is never called.

[paulyoung]

I can only assume that method_exchangeImplementations(defaultSessionConfiguration, mockingjayDefaultSessionConfiguration) is not working as expected, since that line is executed but mockingjayDefaultSessionConfiguration() is never called.

[kylef]

Would you be able to check protocolClasses in NSURLSessionConfiguration inside NSURLSession returns an array of protocols with MockingjayProtocol being the first result?

This should only happen after the first stub was registered via XCTestCase.stub, I'm wondering if NSURLSession makes a copy of the protocols before this is registered.

If this isn't the case, perhaps you could try explicitly exchanging these methods by calling the following before anything related to NSURLSession happens:

NSURLSessionConfiguration.mockingjaySwizzleDefaultSessionConfiguration()

If this solves the problem, then we will need to revisit where this exchange is done within Mockingjay.

[paulyoung]

I'm planning on looking into this when I get chance.

[tamamachi]

I think I encountered the same problem when I updated Mockingjay form 1.1.0 to 1.1.1.
I'm using Quick and adding NSURLSessionConfiguration.mockingjaySwizzleDefaultSessionConfiguration() to beforeSuite worked like a charm!
Thanks a lot.

[krodak]

@kylef I can confirm too that currently, method swizzling doesn't work.
I tried @paulyoung approach but to no avail.
Even if I put swizzling in AppDelegate it won't replace the default session.

[ffrddrll]

I simply use MockingjayProtocol.addStub(matcher: Matcher, builder: Builder) instead of stub(matcher: Matcher, builder: Builder) for my test. It worked.

[IvanRublev]

Swizzling works for Xcode 7.2 and Swift 2.1.1. And stubbing goes well.
Check the order in which stubbing (and as consequence swizzling) and creation of NSURLSession instance occurs.

For example, if you use the Alamofire and your tested target is calling Alamofire.Manager.sharedInstance somewhere on the app's start, then this sharedInstance's underlying NSURLSession object's configuration is not swizzeled with Mockingjay protocol. It's because the sharedInstance is initialized on Manager class load. And that occurs before your test starts and swizzling occurs.)

To workaround this you should redesign your app or test to use the custom Manager instance. If you make Mockingjay to swizzle before initializing the Manager instance:

NSURLSessionConfiguration.mockingjaySwizzleDefaultSessionConfiguration()
let requestManager = Manager(configuration: NSURLSessionConfiguration.defaultSessionConfiguration())

Then requests to the requestManager will be stubbed successfully.