anchor.diff:      [<TestMethod>]
       member __.``Change window start`` () =
   
  -        let bh = { DownrangeWindow = { Start = 3.0<m>; End = 5.0<m> } }
  -        let newWindowStart = bh.DownrangeWindow.Start + 0.1<m>
  +        let initialStart, initialEnd = 3.0<m>, 5.0<m>
  +        let bh = { DownrangeWindow = { Start = initialStart; End = initialEnd } }
  +        let newWindowStart = initialStart + 0.1<m>
  +        let expectedWindow = { bh.DownrangeWindow with Start = newWindowStart }
           let change = ChangeWindowStart newWindowStart
           let systemContext = {
               SystemType = ArisSystemType.Aris3000
  
positive.code: 
          let changed = bunnyHillProjection.Change.Invoke(bh, systemContext, change)
  
          Assert.AreEqual(bh.DownrangeWindow.Start, changed.DownrangeWindow.Start)
          Assert.AreEqual(newWindowEnd, changed.DownrangeWindow.End)
  
negative.code: 
          let changed = bunnyHillProjection.Change.Invoke(bh, systemContext, change)
  
          let actualWindow = changed.DownrangeWindow
          Assert.AreEqual<DownrangeWindow>(expectedWindow, actualWindow)
  
      [<TestMethod>]
      member __.``Change window end`` () =
  
          let initialStart, initialEnd = 3.0<m>, 5.0<m>
          let bh = { DownrangeWindow = { Start = initialStart; End = initialEnd } }
          let newWindowEnd = initialEnd + 0.1<m>
          let expectedWindow = { bh.DownrangeWindow with End = newWindowEnd }
          let change = ChangeWindowEnd newWindowEnd
  
          let systemContext = {
              SystemType = ArisSystemType.Aris3000
              WaterTemp = 20.0<degC>
  