anchor.diff:  
           let vals = o.Take(3).ToEnumerable() |> Array.ofSeq
   
  -        Assert.True([| 1; 2; 3 |] = vals)
  +        Assert.Equal<int[]>([| 1; 2; 3 |], vals)
  
positive.code:         let binding = (a, id) @~> b
  
          a <~ 5
          Assert.True(!!b = 5)
  
          a <~ 6
          Assert.True(!!b = 6)
  
          binding.Dispose()
  
          a <~ 7
          Assert.True(!!b = 6)
  
      [<Fact>]
      let ``two-way binding should work`` () =
  
negative.code:         let p = oref 0
  
          p <~ 5
          Assert.Equal(5, !!p)
  
          p <~ 6
          Assert.Equal(6, !!p)
  
      [<Fact>]
      let ``property changes should be observed correctly`` () =
  