Specs Presentation

1. Specs _ what it is Scala library for Behaviour-Driven Development. See the associated code for a working example - HelloWorldSpec.scala import org.specs._ object HelloWorldSpec extends Specification { "'hello world' has 11 characters" in { "hello world" .size must_== 11 } "'hello world' matches 'h.* w.*'" in { "hello world" must beMatching( "h.* w.*" ) } } [info] Running specs tests... [info] [info] Testing scalamelb.specs.HelloWorldSpec ... [info] specifies [info] + 'hello world' has 11 characters [info] + 'hello world' matches 'h.* w.*' [info] [info] All tests PASSED.

2. Specs _ structure BDD builds on TDD to allow tests to be written in the business domain language.

3. The Specs structure: Specify system (with context) and examples "An empty stack" should "be of size zero" NigerianPrinceSpec.scala "A Nigerian prince with access to an email account" should { "contact you in relation to his most generous offer" in { // exercise the logic and make assertions ... } }

4. Specs _ structure Examples can be nested

5. Systems can't

6. Specifications can, sort of SnowflakeSpec.scala "A snowflake" should { [info] A snowflake should "be cold" in { [info] + be cold "and icy" in { … } [info] + and icy "and unique" in { … } [info] + and unique "A snowflake" should { "in the desert" should { "melt" in { … } object SnowflakeSpec extends Specification { "A snowflake" isSpecifiedBy SnowflakeInTheDesertSpec , SnowflakeInTheFrideSpec , SnowflakeOnTheTongueSpec }

7. Specs _ matchers Matchers are the assertion mechanism. Allow natural language assertions

8. 100+ are documented at time of writing (v1.4.4)

9. Can write custom matchers. Can be combinatorial. PhoneBillSpec.scala "A phone bill" should { "keep a count of calls made" in { bill.numberOfCallsMade must_== 3 "A phone bill" should { "include a call to my mother" in { bill.callsMade must contain ("9898 4477") "A phone bill" should { "export calls to file" in { bill.exportFile must (beReadable and not(beHidden))

10. Specs _ scalacheck Matcher for ScalaCheck (A test case automation tool)

11. Default of 100 arbitrary test input values per statement

12. For all n (where n >=0) √n² must equal n SquareRooter.scala object SquareRooterSpec extends Specification with ScalaCheck { "A Square Rooter" should { "find the originally squared value (as long as it wasn't negative)" in { // forAll { (n: Int) => scala.Math.sqrt(n*n) == n } must pass // fails on -1 forAll { n: Int => n >= 0 ==> (scala.Math.sqrt(n*n) == n) } must pass

13. Specs _ tear up / down Traditional setup & teardown mechanisms available for before and after: Specification

14. each System

15. each Example SetupAndTeardown.scala object SetupAndTeardown extends Specification { doBeforeSpec{ println( "Specification setup" ) } doFirst{ println( "System setup" ) } doBefore{ println( "Example setup" ) } … doAfter{ println( "example teardown" ) } doLast{ println( "System teardown" ) } doAfterSpec{ println( "Specification teardown" ) } }

16. Specs _ shared contexts Before and after context blocks can be encapsulated in Context values and "threaded" into Systems.

17. They come with a warning – expect the unexpected if shared and mutated in different Systems within the Specification. And don't feed after midnight. ThreadedLists.scala var listOfStrings:List[ String ] = Nil val withThreeValues = beforeContext { listOfStrings = "bob" :: "harry" :: "dorothy" :: Nil } "A list of three Strings" ->-(withThreeValues) should { "be of three strings long" in { listOfStrings.length must_== 3 } }

18. Specs _ system contexts Alternatively, System Contexts can be constructed to always return a system in a given state.

19. They come in two flavours: Internal (a SystemContext instance)

20. External (a case class extending SystemContext) MonkeyKing.scala object MonkeyKingSpec extends Specification with SystemContexts { /* Demonstrates explicit, internal system context. See example for more. */ "The monkey king under attack" should { val monkeyKingUnderAttack = systemContext { new MonkeyKing ( true ) } "summon warriors from his ear hairs" .withA(monkeyKingUnderAttack) { monkeyKing => monkeyKing.summonsWarriorsFromEarHair must beTrue

21. Specs _ mocking Both jMock and Mockito can be mixed-in Specs adds syntactic sugar to ease mocking USBLightSpec.scala object USBLightSpec extends Specification with Mockito { "A green USB light" should { "be observed but not adjusted" in { val light = mock[ Light ] light.getColour returns Green val colour = LightObserver(light).observeLightsColour colour must_== Green light.getColour was called light.setIntensity _ wasnt called

22. Specs _ alternatives ScalaTest

23. Instinct class StackSpec extends Spec with ShouldMatchers { describe( "A newly created Stack" ) { val stack = new Stack[Any] it( "should be empty" ) { stack should be ('empty) } } } class ANewlyCreatedStack { val stack = new Stack[Any] @Specification def shouldBeEmpty = { expect that stack.depth isEqualTo 0 } }

Specs Presentation

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Specs Presentation