anchor.diff:      let model = 
           [ @"..\Rx-Main\lib\net40\Rx.dll"; @"..\Rx-Main\lib\net45\Rx.dll" ] 
           |> extractFrameworksFromPaths InstallModell.EmptyModel
  -    model.GetFiles(DotNetFramework(Framework "v4.0", Full)) |> shouldContain (@"..\Rx-Main\lib\net40\Rx.dll")
  -    model.GetFiles(DotNetFramework(Framework "v4.5", Full)) |> shouldContain (@"..\Rx-Main\lib\net45\Rx.dll")
  +    model.GetFiles(DotNetFramework(Framework "v4.0", Full)) |> shouldContain @"..\Rx-Main\lib\net40\Rx.dll"
  +    model.GetFiles(DotNetFramework(Framework "v4.5", Full)) |> shouldContain @"..\Rx-Main\lib\net45\Rx.dll"
   
   [<Test>]
   let ``should add net35 if we have net20 and net40``() = 
  
positive.code:         |> extractFrameworksFromPaths InstallModell.EmptyModel
          |> useLowerVersionLibIfEmpty
  
      model.GetFiles(DotNetFramework(Framework "v2.0", Full)) |> shouldContain (@"..\Rx-Main\lib\net20\Rx.dll")
      model.GetFiles(DotNetFramework(Framework "v3.5", Full)) |> shouldContain (@"..\Rx-Main\lib\net20\Rx.dll")
      model.GetFiles(DotNetFramework(Framework "v4.0", Full)) |> shouldContain (@"..\Rx-Main\lib\net40\Rx.dll")
      model.GetFiles(DotNetFramework(Framework "v4.0", Full)) |> shouldNotContain (@"..\Rx-Main\lib\net20\Rx.dll")
      model.GetFiles(DotNetFramework(Framework "v4.5", Full)) |> shouldContain (@"..\Rx-Main\lib\net40\Rx.dll")
      model.GetFiles(DotNetFramework(Framework "v4.5.1", Full)) |> shouldContain (@"..\Rx-Main\lib\net40\Rx.dll")
  
  [<Test>]
  let ``should put _._ files into right buckets``() = 
      let model = 
          [ @"..\Rx-Main\lib\net40\_._"; @"..\Rx-Main\lib\net20\_._" ] 
          |> extractFrameworksFromPaths InstallModell.EmptyModel
      model.GetFiles(DotNetFramework(Framework "v2.0", Full)) |> shouldContain (@"..\Rx-Main\lib\net20\_._")
      model.GetFiles(DotNetFramework(Framework "v4.0", Full)) |> shouldContain (@"..\Rx-Main\lib\net40\_._")
  
  [<Test>]
  let ``should skip buckets which contain placeholder while adjusting upper versions``() = 
  
negative.code:         |> extractFrameworksFromPaths InstallModell.EmptyModel
          |> useLowerVersionLibIfEmpty
  
      model.GetFiles(DotNetFramework(Framework "v3.5", Full)) |> shouldNotContain @"..\Castle.Core\lib\net40-client\Castle.Core.dll"
      model.GetFiles(DotNetFramework(Framework "v4.0", Client)) |> shouldContain @"..\Castle.Core\lib\net40-client\Castle.Core.dll" 
      model.GetFiles(DotNetFramework(Framework "v4.0", Full)) |> shouldContain @"..\Castle.Core\lib\net40-client\Castle.Core.dll"
      model.GetFiles(DotNetFramework(Framework "v4.5", Full)) |> shouldContain @"..\Castle.Core\lib\net40-client\Castle.Core.dll"