Re: Unit testing

We must not also not forget that the creator of ScalaCheck, Rickard Nilsson, is an awesome guy.

On Tue, Feb 24, 2009 at 8:02 PM, Bill Venners <bill@artima.com> wrote:

Hi Russel,

There are three production-ready testing frameworks for Scala, and
they are each aimed at different goals:

ScalaCheck enables property-based testing, in which you write a
"property" in one or a few lines of code, and it automatically
generates test cases for you, including attempting to test edge
conditions.

Specs enables a behavior-driven development style of testing, in which
you write tests first using specification like terms, and the output
of the test reads as an informal specification of the system under
test.

ScalaTest is designed to facilitate different styles of testing. It
also facilitates a behavior-driven development style of testing
similar to Specs, but with a different syntax. (And in the next
release, coming this week, will have its own matchers DSL which really
I think shows off the awesomeness of Scala's DSL capabilities.) But if
you don't drink the BDD koolaid, you can also use ScalaTest to test in
more traditional styles, or to use nicer syntax when writing JUnit or
TestNG tests in Scala.

You can use ScalaCheck from either Specs or ScalaTest, and you can use
Specs from ScalaTest and vice versa, so everything is fairly
integrated with each other. I think everyone should look at
ScalaCheck, but probably use it from either ScalaTest or Specs,
because they are more general. I find I still need to write a lot of
non-property-based tests even though I use ScalaCheck properties as
much as I can. So if you don't like BDD, or want (or need) to be
writing JUnit or TestNG tests, the ScalaTest is the way to go. If you
like the BDD style, then either ScalaTest or Specs will work, and you
can pick whichever syntax you prefer.

Bill

On Tue, Feb 24, 2009 at 10:01 AM, Russel Winder
<russel.winder@concertant.com> wrote:
> If I type "unit test" as a search term on the http://www.scala-lang.org/
> page the first mention of a unit test framework is item 8 "ScalaCheck
> 1.5" and there are only 11 items.
>
> Type "Scala unit test" at Google and the principle item is Ola Bini's
> little rant about the lack of unit test framework for Scala.  Well
> actually he comes up with SUnit, ScUnit, Rehersal, ScalaCheck and Specs.
> To this add ScalaTest.  Also of course there is TestNG and the venerable
> JUnit which are the Java unit test frameworks that can be used from
> Scala.
>
> So my question is:  has the Scala community decided on which framework
> will be deemed the de facto standard one?
>
> Unit testing became the accepted norm in Java programming partly because
> there was one standard framework, JUnit.  TestNG arose because of
> JUnit's post Java 1.5 deficiencies, and JUnit 4 is really a pale
> imitation of TestNG.  Unit testing is still relatively rare in C and C++
> and one can probably show that one of the factors is that there is a
> plethora of unit testing frameworks and none of them are looked at as de
> facto standard.
>
> So for unit testing to become strong in Scala programming it would be
> good if there was one or perhaps two de facto or actual standard
> frameworks.  SUnit clearly fails to be this for whatever reason.
>
> Is the de facto standard therefore actually TestNG?
>
> I suspect I should immediately ask that all flames and trolls be
> directed to /dev/null.  I want to move development from Java to Scala
> and genuinely need an answer to "Which unit test framework is the
> standard one".
>
> Thanks.
> --
> Russel.
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