Lightweight specs

The default Specification class mixes in most of specs2 features in order to make it very easy to write your first specifications without worrying too much about where the feature resides.

There at least 2 downsides to this approach:

inside a Specification you get lots of inherited method names, encumbering the namespace
many of the traits mixed-in the Specification class define implicit methods and those methods have a big impact on compilation times

It is thus possible to use another class, org.specs2.Spec (or org.specs2.mutable.Spec), which only provides the minimum number of implicits to create specifications.

With the Spec class you can create examples and expectations with simple matchers. For example:

class HelloWorldSpec extends Spec { def is = s2"""

 This is a specification to check the 'Hello world' string

 The 'Hello world' string should
   contain 11 characters                                         $e1
   start with 'Hello'                                            $e2
   end with 'world'                                              $e3
                                                                 """

 def e1 = "Hello world" must haveSize(11)
 def e2 = "Hello world" must startWith("Hello")
 def e3 = "Hello world" must endWith("world")
}

Or, for mutable specs:

class HelloWorldSpec extends mutable.Spec {

  addParagraph("This is a specification to check the 'Hello world' string")

 "The 'Hello world' string" should {
   "contain 11 characters" in {
     "Hello world" must haveSize(11)
   }
   "start with 'Hello'" in {
     "Hello world" must startWith("Hello")
   }
   "end with 'world'" in {
     "Hello world" must endWith("world")
   }
 }

}

If you compare those 2 specifications with the “HelloWorldSpec” examples using Specification you will notice some differences:

you cannot write "Hello world" must have size(11)
you cannot write "This is a specification to check the 'Hello world' string".txt to add some text to a mutable spec

But not all is lost! For each functionality you might want to use there is a trait which you can mix-in to get it.

Adding features

When creating expectations:

Feature	Trait	Comment
Use `should` for expectations	`org.specs2.matcher.ShouldMatchers`
Describe expectations with `==>`	`org.specs2.matcher.ExpectationsDescription`
Describe expectations with `aka` and `must`	`org.specs2.matcher.MustExpectations`
Use `list must have size(3)`	`org.specs2.matcher.TraversableMatchers`	For each matcher you want to use after `be/have/not`, you need to mix-in the corresponding matchers trait
Use matchers in `contain` or `beSome` matchers	`org.specs2.matcher.ValueChecks`
Use `===`, `====` to check for equality	`org.specs2.matcher.TypedEqual`
Create matchers from functions	`org.specs2.matcher.MatchersCreation`
Combine `MatchResults` with `and/or`	`org.specs2.matcher.MatchResultsCombinators`
Transform a `Matcher[T]` to `Matcher[Seq[T]]`	`org.specs2.matcher.SequenceMatchersCreation`
Use `forall(values)(t => t must xxx)`	`org.specs2.matcher.SequenceMatchersCreation`	You can combine all matchers features by using the `org.specs2.matcher.MatchersImplicits` trait

When creating acceptance specifications

Feature	Trait	Comment
Interpolate anything else than a `Result` in a `s2` string	`org.specs2.specification.create.S2StringContext`
Use “bang” examples: `"example" ! ok`	`org.specs2.specification.dsl.ExampleDsl`
Create and append `Fragments` with `^`	`org.specs2.specification.dsl.FragmentsDsl`
Add arguments and a title to `Fragments` with `^`	`org.specs2.specification.dsl.SpecStructureDsl`
Create a title with `"A title".title"`	`org.specs2.specification.dsl.TitleDsl`
Create references to other specifications	`org.specs2.specification.dsl.ReferenceDsl`
Create steps and actions	`org.specs2.specification.dsl.ActionDsl`
Use tags	`org.specs2.specification.dsl.TagDsl`	To use all of the `Dsl` traits use `AcceptanceDsl`

When creating mutable specifications

Feature	Trait	Comment
Use “bang” examples: `"example" ! ok`	`org.specs2.specification.dsl.mutable.ExampleDsl`
Create a title with `"A title".title"`	`org.specs2.specification.dsl.mutable.TitleDsl`
Set arguments	`org.specs2.specification.dsl.mutable.ArgumentsDsl`
Create references to other specifications	`org.specs2.specification.dsl.mutable.ReferenceDsl`
Create steps and actions	`org.specs2.specification.dsl.mutable.ActionDsl`
Add text and paragraphs	`org.specs2.specification.dsl.mutable.TextDsl`
Use tags	`org.specs2.specification.dsl.mutable.TagDsl`	To use all of the `Dsl` traits use `MutableDsl`