Category on NSDate to return a random date in the same year as itself.

NSDate+RandomDate.h

//
//  NSDate+RandomDate.h
//
//

#import <Foundation/Foundation.h>

@interface NSDate (RandomDate)

- (NSDate *)randomDateInYearOfDate;

@end

NSDate+RandomDate.m

//
//  NSDate+RandomDate.m
//
//

#import "NSDate+RandomDate.h"

@implementation NSDate (RandomDate)

- (NSDate *)randomDateInYearOfDate {
    NSCalendar *currentCalendar = [NSCalendar currentCalendar];
    NSDateComponents *comps = [currentCalendar components:NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit fromDate:self];
    
    [comps setMonth:arc4random_uniform(12)];
    
    NSRange range = [[NSCalendar currentCalendar] rangeOfUnit:NSDayCalendarUnit inUnit:NSMonthCalendarUnit forDate:[currentCalendar dateFromComponents:comps]];
    
    [comps setDay:arc4random_uniform(range.length)];
    
    // Normalise the time portion
    [comps setHour:0];
    [comps setMinute:0];
    [comps setSecond:0];
    [comps setTimeZone:[NSTimeZone timeZoneWithName:@"GMT"]];
    
    return [currentCalendar dateFromComponents:comps];
}

@end

Please convert it for Swift 3.x +