Add keywords

Mutable specifications offer a predefined “vocabulary” to define examples:

import org.specs2.*

class MySpecification extends mutable.Specification:
  "the 'and' function" should {
    "return true when passed true, true" >> {
      (true && true) === true
    }
    "return false when passed true, false" >> {
      (true && false) === false
    }
  }

This will print:

 the 'and' function should
   + return true when passed true, true
   + return false when passed true, false

And you can see that the word “should” has been added to the first description.

However one size does not fit all and you might want to add your own predefined words. Here is how to do it:

import org.specs2.*
import org.specs2.specification.core.{Fragment, Fragments}
import org.specs2.specification.dsl.mutable.*

trait ToKeyword extends ExtendedBlockDsl:
  extension (description: String)
    infix def to(f: =>Fragment): Fragment =
      (description + " to") >> f

    // this implementation of `to` uses an implicit parameter. This is used to overload
    // the method for different arguments: Fragment and Fragments
    @targetName("toFs")
    infix def to(fs: =>Fragments): Fragments =
      (description + " to") >> fs

class MySpecification extends org.specs2.mutable.Specification with ToKeyword:

  "the 'and' function is used" to {
    "return true when passed true, true" >> {
      (true && true) === true
    }
    "return false when passed true, false" >> {
      (true && false) === false
    }
  }

Now this will print

 the 'and' function is used to
   + return true when passed true, true
   + return false when passed true, false