Set iPhone date/time within app for testing purposes?

Question

I have a lot of functionality in my app that is date/time dependent (e.g. "if date is x, show y). I use [NSDate date] to get the current date/time of the user. I can test functionality by manually changing the date/time on my iPhone but I'm wondering if there is a way to programatically overwrite the the current time so I can test in the simulator and more quickly.

Answer 1

Another way of doing it is to provide a custom implementation of +(NSDate *)date. You can swizzle this class method using JRSwizzle. Make a small category for the NSDate:

static NSTimeInterval seconds = 1300000000;

@interface NSDate (Fixed)
   + (NSDate *)fixedDate;
@end

@implementation NSDate (Fixed)
+ (NSDate *)fixedDate
{
  return [NSDate dateWithTimeIntervalSince1970:seconds];
}
@end

Then in the code where you want to have fixed date do the following:

NSError *error;
[NSDate jr_swizzleClassMethod:@selector(date) withClassMethod:@selector(fixedDate) error:&error];
NSLog(@"Date:%@", [NSDate date]);

The log prints out this:

2011-09-01 11:35:27.844 tests[36597:10403] Date:2011-03-13 07:06:40 +0000