<p>How do I test if two dates are within a certain tolerance in NUnit?</p>

Convert your tolerance to Ticks and then use an And constraint. Something like;
```
```
long ticks = mydate.Ticks;
long tolerance = 1000;
Assert.That( ticks, Is.LessThan( ticks + tolerance ) & Is.GreaterThan( ticks - tolerance ) );
```
```
I would create an extension method or your own Assert to do this though.