For example, this trait enables syntax such as the following test registration in FlatSpec and FixtureFlatSpec:

 "A Stack (when empty)" can "be empty" in { ... }
                        ^
 

It also enables syntax such as the following shared test registration in FlatSpec and FixtureFlatSpec:

 "A Stack (with one item)" can behave like nonEmptyStack(stackWithOneItem, lastValuePushed)
                           ^
 

In addition, it supports the registration of subject descriptions in WordSpec and FixtureWordSpec, such as:

 "A Stack (when empty)" can { ...
                        ^
 

And finally, it also supportds the registration of subject descriptions with after words in WordSpec and FixtureWordSpec. For example:

    def provide = afterWord("provide")

   "The ScalaTest Matchers DSL" can provide {
                                ^
 

The reason this implicit conversion is provided in a separate trait, instead of being provided directly in FlatSpec, WordSpec, FixtureFlatSpec, and FixtureWordSpec, is primarily for design symmetry with ShouldVerb and MustVerb. Both ShouldVerb and MustVerb must exist as a separate trait because an implicit conversion provided directly would conflict with the implicit conversion that provides should or must methods on String in the ShouldMatchers and MustMatchers traits.