XCTestCase (Debugging)

XCTestCase+DebuggingAdditions.m

#import <objc/runtime.h>

@implementation XCTestCase (Debugging)

+ (XCTestSuite *)debug_defaultTestSuite {
    NSString *className = NSStringFromClass(self);
    
    // Only run tests that start with SQR.
    if ([className rangeOfString:@"SQR"].location != 0) {
        return nil;
    }
    
    // Calls the original method.
    return [self debug_defaultTestSuite];
}

+ (void)load {
    // Swizzle defaultTestSuite
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        Class class = object_getClass((id)self);
        
        SEL originalSelector = @selector(defaultTestSuite);
        SEL swizzledSelector = @selector(debug_defaultTestSuite);
        
        Method originalMethod = class_getClassMethod(class, originalSelector);
        Method swizzledMethod = class_getClassMethod(class, swizzledSelector);
        
        
        BOOL didAddMethod =
        class_addMethod(class,
                        originalSelector,
                        method_getImplementation(swizzledMethod),
                        method_getTypeEncoding(swizzledMethod));
        
        if (didAddMethod) {
            class_replaceMethod(class,
                                swizzledSelector,
                                method_getImplementation(originalMethod),
                                method_getTypeEncoding(originalMethod));
        } else {
            method_exchangeImplementations(originalMethod, swizzledMethod);
        }
    });
}

@end