F# development and unit testing?

 

I just got started with F#, which is my first functional language. I have been working quasi-exclusively with C#, and enjoy a lot how F# leads me to re-think how I write code. One aspect I find a bit disorienting is the change in the process of writing code. I have been using TDD for years in C# now, and really appreciate to have unit tests to know where I am at.

So far, my process with F# has been to write some functions, play with them with the interactive console until I am "reasonably" sure they work, and tweak & combine. This works well on small-scale problems like the Euler Project, but I can't imagine building something large that way.

How do people approach unit testing and building a test suite for a F# program? Is there an equivalent to TDD? Any pointers or thoughts are appreciated.

Test-driven developers should feel right at home in functional languages like F#: small functions that give deterministically repeatable results lend themselves perfectly to unit tests. There are also capabilities in the F# language that facilitate writing tests. Take, for example, Object Expressions. You can very easily write fakes for functions that take as their input an interface type.

If anything, F# is a first-class object-oriented language and you can use the same tools and tricks that you use when doing TDD in C#. There are also some testing tools written in or specifically for F#:

  • NaturalSpec
  • FsCheck
  • FsTest
  • FsUnit

    • Matthew Podwysocki wrote a great series on unit testing in functional languages. Uncle Bob also wrote a thought provoking article here.

    I use NUnit, and it doesn't strike me as hard to read or onerous to write: 

    open NUnit.Framework

[<TestFixture>]
type myFixture() = class

    [<Test>]
    member self.myTest() =
       //test code

end

    Since my code is a mix of F# and other .Net languages, I like the fact that I write the unit tests in basically the same fashion and with similar syntax in both F# and C#.

    Have a look at FsCheck , an automatic testing tool for F#, is basically a port of Haskell's QuickCheck. It allows you to provide a specification of the program, in the form of properties that the functions or methods should satisfy, and FsCheck tests that the properties hold in a large number of randomly generated cases.

    FsCheck CodePlex Page

    FsCheck Author Page

    链接地址: http://www.djcxy.com/p/80862.html

    上一篇: F＃vs Haskell vs Lisp

    下一篇: F＃开发和单元测试？