title: NUnit keeping static data across tests
body: <p>I have a static class that I'm using to hold my test data.  When I reference this in my NUnit tests, any changes I make are persisted across tests.</p>
  
  <p>For example, I have this code in my test:</p>
  
  <pre><code>OrderDto orderDto = SampleData.OrderDto;
  OrderDetailDto orderDetailDto = SampleData.OrderDetailDto;
  orderDto.OrderDetails.Add(orderDetailDto);
  </code></pre>
  
  <p>And sample data is something like this:</p>
  
  <pre><code>public static class SampleData {
      public static OrderDto OrderDto = new OrderDto { LastName = "Smith", CreatedById = 5, CreatedByDisplayName = "Smith2" };
  }
  </code></pre>
  
  <p>The first time I run it, orderDto has 0 OrderDetails.  The second time it has 1, then 2, etc.  I thought between NUnit tests, nothing was persisted.  Does it cache static properties?</p>