anchor.diff:      // Exercise system
       sut.Customize(fixtureStub)
       // Verify outcome
  -    Assert.Empty(customizations)
  +    verify <@ customizations |> Seq.isEmpty @>
       // Teardown
   
  
positive.code:     // Exercise system
      sut.Customize(fixtureStub)
      // Verify outcome
      Assert.Contains(sut.Relay, residueCollectors)
      // Teardown
  
  [<Fact>]
  
negative.code: open Ploeh.AutoFixture
  open Ploeh.AutoFixture.AutoFoq
  open Ploeh.AutoFixture.Kernel
  open Swensen.Unquote.Assertions
  open Xunit
  open System
  open System.Collections.Generic
  
  let private verify = Swensen.Unquote.Assertions.test
   
  [<Fact>]
  let SutIsCustomization() =
  