barrier to legacy code.cs

public class SomeNewCode
{
  private ISomeOldCode {get; set; }
  public SomeNewCode(ISomeOldCode someOldCode)
  {
    SomeOldCode = someOldCode;
  }
}

public interface ISomeOldCode
{
  public void DoSomething();
}

public class SomeOldCodeAdapater: ISomeOldCode
{
  public void DoSomething()
  {
    SomeOldCode.DoSomething();
  }
}

public static class SomeOldCode
{
  public static void DoSomething()
  {
    ... the real work happens here, but it's in a static method / object, so it needs a safety barrier between it and the code that wants to be unit tested, above.
  }
}