A perfect example of listening to your tests, and appropriately abandoning ship (i.e., rethink that design)

gistfile1.m

#import <SenTestingKit/SenTestingKit.h>
#import "OCMock.h"
#import "SenTestCase+MethodSwizzling.h"
#import <objc/runtime.h>

#import "NLWelcomeViewController.h"
#import "NLWelcomeFlowGoogleViewController.h"

#pragma mark Setup

static NSString * const mobileToken = @"<some token>";
static NSString * const mobileUsername = @"asardone%40nutshell.com";
static NSString * const emailAddress = @"asardone@nutshell.com";

@implementation UIViewController (NLWelcomeFlowGoogleViewControllerTests)

- (NLWelcomeViewController *)nl_welcomeViewController
{
    static char *nl_welcomeViewControllerForTestsKey = "nl_welcomeViewControllerForTests";
    id result = objc_getAssociatedObject(self, nl_welcomeViewControllerForTestsKey);
    if (!result) {
        result = [OCMockObject niceMockForClass:[NLWelcomeViewController class]];
        objc_setAssociatedObject(self, nl_welcomeViewControllerForTestsKey, result, OBJC_ASSOCIATION_RETAIN);
    }
    return result;
}

@end

@interface FakeHTTPCookieStorage : NSObject

+ (NSHTTPCookieStorage *)sharedHTTPCookieStorage;

@end

@implementation FakeHTTPCookieStorage

+ (NSHTTPCookieStorage *)sharedHTTPCookieStorage
{
    NSHTTPCookie *usernameCookie = [NSHTTPCookie cookieWithProperties:[NSDictionary dictionaryWithObjectsAndKeys:
                                                                       @"api.nutshell.com", NSHTTPCookieDomain,
                                                                       @"/google", NSHTTPCookiePath,
                                                                       @"mobile_username", NSHTTPCookieName,
                                                                       mobileUsername, NSHTTPCookieValue,
                                                                       nil]];
    NSHTTPCookie *tokenCookie = [NSHTTPCookie cookieWithProperties:[NSDictionary dictionaryWithObjectsAndKeys:
                                                                    @"api.nutshell.com", NSHTTPCookieDomain,
                                                                    @"/google", NSHTTPCookiePath,
                                                                    @"mobile_token", NSHTTPCookieName,
                                                                    mobileToken, NSHTTPCookieValue,
                                                                    nil]];

    NSArray *fakeCookies = [NSArray arrayWithObjects:
                            usernameCookie,
                            tokenCookie,
                            nil];

    id fakeHTTPCookieStorage = [OCMockObject niceMockForClass:[NSHTTPCookieStorage class]];
    [[[fakeHTTPCookieStorage stub] andReturn:fakeCookies] cookies];
    return fakeHTTPCookieStorage;
}

@end

#pragma mark - Tests

@interface NLWelcomeFlowGoogleViewControllerTests : SenTestCase

@end

@implementation NLWelcomeFlowGoogleViewControllerTests

- (void)testGiveWelcomeViewControllerCredentialsOnSuccessfulGoogleAuth
{
    // neighborhood
    NSURL *authURL = [NSURL URLWithString:@"https://auth.example.com"];
    NSString *authEmail = emailAddress;

    // system under test
    id googleVC = [[NLWelcomeFlowGoogleViewController alloc] initWithAuthenticateURL:authURL
                                                                               email:authEmail];

    // expectations
    id welcomeVC = [googleVC nl_welcomeViewController];
    [[welcomeVC expect] googleAuthScreenCompletedWithUsername:emailAddress password:mobileToken];

    [self swizzleClassMethod:@selector(sharedHTTPCookieStorage)
                     inClass:[NSHTTPCookieStorage class]
             withClassMethod:@selector(sharedHTTPCookieStorage)
                   fromClass:[FakeHTTPCookieStorage class]
                executeBlock:^
                {
                    UIWebView *fakeSuccessfulWebView = [OCMockObject niceMockForClass:[UIWebView class]];
                    [googleVC webViewDidFinishLoad:fakeSuccessfulWebView];

                    // assert
                    [welcomeVC verify];
                }
    ];
}

@end