5.12.15 QA Lab: тестирование программного обеспечения. Upcoming events: goo.gl/I2gJ4H Доклад о Play-Swagger, проекте с открытым исходным кодом, разрабатываемом в Zalando с использованием Scala и Play Framework. О том, как использование API First и Swagger позволяет ускорить процесс разработки, упростить взаимодействие команд и повысить качество продукта.

1. Self-testing REST APIs
with
API First, Swagger and Play

2. You need two days to write test cases!?
You already have the Requirements Specification.
Just copy and paste from it.
http://inderpsingh.blogspot.de/2010/05/funny-things-that-testers-hear.html

3. Specification

4. Specification

5. Specification

6. Specification
Architectural style

7. Specification
Architectural style
Technological stack

8. Architectural style

9. Architectural style
REST

10. REST
• Client-Server
• Stateless
• Cacheable
• Layered System
• Uniform Interface
• Identification of resources
• Manipulation of resources through these representations
• Self-descriptive messages
• Hypermedia as the engine of application state

11. Everybody's doing it…

15. Testers, how are you doing it?

17. All of them are just different views of
the same piece of software…

18. What is software?

19. Simple
the programs that run on a computer and perform certain
functions

20. something used or associated with and usually contrasted
with hardware as the entire set of programs, procedures,
and related documentation associated with a system and
especially a computer system.
Full

21. Can you remember quality metrics of your current project?
Libraries it uses?
Runtime environment it runs in?
Container or/and hypervisor?
Operating system?
Firmware/BIOS ?

22. [A] constructive approach to the problem of program
correctness [is] a usual technique to make a program and
then to test it. But, program testing can be a very effective
way to show the presence of bugs, it is hopelessly
inadequate for showing their absence. The only effective
way to raise the confidence level of a program significantly
is to give a convincing proof of its correctness.
-- Edsger, Wybe Di jkstra, ACM Turing Lecture, The Humble Programmer, 1972

23. Property based testing

24. Types are specifications of possible values complying to that Type
Types describe the rules that values must comply to
A possibility to generate ranges of data values for given Types

25. Boolean: True or False
Equality: Equal or Not Equal
Ordering: Greater, Equal or Less
Provable

26. Numbers
Strings
Pretty much anything not composed from Provables
Falsifiable

27. Let’s look again at our system

29. aka Ports and Adapters
Chris Fidao
https://www.youtube.com/watch?v=6SBjKOwVq0o

30. Specification
Architectural style
Technology stack
Let’s look again at our solution space

31. Transport
Transport
Validations
Validations
Model
Model

32. DRY

33. DRY
Most people take DRY to mean you shouldn't duplicate code.
That's not its intention. The idea behind DRY is far grander
than that. DRY says that every piece of system knowledge
should have one authoritative, unambiguous representation.
Dave Thomas

34. Specification is software
It should be a single source of
truth about the system

35. Formal specification gives us:
Possibility to prove implementation conformance
Self-Evident poorly specified areas
Self-Documented API definition
Intelligent scaffolding
http://www.heppenstall.ca/academics/doc/320/L15_Z.pdf

36. You need two days to write test cases!?
You already have the requirements specification.
Just copy and paste from it.

37. Specification
Architectural style
Technology stack
Let’s look again at our technology choice

38. • Easy to use
• Human readable
• Widest adoption
• Open Source
• Scala and Java
• Dynamic recompilation
• Hot reload
• Asynchronous IO
• Easy to use

39. Specification
URLs
Verbs
Parameters
Security
Definitions

40. Specification
URLs
Verbs
Parameters
Security
Definitions Validations
Model
Test Data
Validations
Play Routes
Marshallers
Tests
Controllers

41. DEMO

42. Architecture

43. AST
Play
Akka HTTP
Swagger
RAML
Apiary
Blueprint
…
…
…

44. Generated code

45. Metadata
swagger: "2.0"
info:
version: 1.0.0
title: Swagger Petstore
description: A sample API that uses a petstore as an example to
demonstrate features in the swagger-2.0 specification
termsOfService: http://swagger.io/terms/
contact:
name: Swagger API Team
email: foo@example.com
url: http://madskristensen.net
license:
name: MIT
url: http://github.com/gruntjs/grunt/blob/master/LICENSE-MIT
host: petstore.swagger.io
basePath: /api
schemes:
- http
consumes:
- application/json
produces:
- application/json

46. Definitions
definitions:
Pet:
allOf:
- $ref: '#/definitions/NewPet'
- required:
- id
properties:
id:
type: integer
format: int64
NewPet:
required:
- name
properties:
name:
type: string
tag:
type: string
Error:
required:
- code
- message
properties:
code:
type: integer
format: int32
message:
type: string
object definitions {
trait NewPetDef {
def name: String
def tag: Option[String]
}
case class Pet(
id: Option[Long],
name: String,
tag: Option[String]
) extends NewPetDef
case class NewPet(
name: String,
tag: Option[String]
) extends NewPetDef
case class Error(
code: Int,
message: String
)
}

47. Test data
definitions:
Pet:
allOf:
- $ref: '#/definitions/NewPet'
- required:
- id
properties:
id:
type: integer
format: int64
NewPet:
required:
- name
properties:
name:
type: string
tag:
type: string
Error:
required:
- code
- message
properties:
code:
type: integer
format: int32
message:
type: string
object generatorDefinitions {
def createPet = _generate(PetGenerator)
def createNewPet = _generate(NewPetGenerator)
def createError = _generate(ErrorGenerator)
// test data generator for /definitions/Pet
val PetGenerator =
for {
id <- Gen.option(arbitrary[Long])
name <- arbitrary[String]
tag <- Gen.option(arbitrary[String])
} yield Pet(id, name, tag)
// test data generator for /definitions/NewPet
val NewPetGenerator =
for {
name <- arbitrary[String]
tag <- Gen.option(arbitrary[String])
} yield NewPet(name, tag)
// test data generator for /definitions/Error
val ErrorGenerator =
for {
code <- arbitrary[Int]
message <- arbitrary[String]
} yield Error(code, message)
def _generate[T](gen: Gen[T]) = (count: Int) =>
for (i <- 1 to count) yield gen.sample
}

48. Validations'#/definitions/NewPet'
red:
rties:
ype: integer
ormat: int64
s:
string
string
ge
s:
integer
t: int32
:
string
class PetValidation(instance: Pet) {
import de.zalando.play.controllers.PlayValidations._
val allValidations = Seq.empty[scala.Either[scala.Seq[ParsingError], String]]
val result = {
val errors = allValidations.filter(_.isLeft).flatMap(_.left.get)
if (errors.nonEmpty) Left(errors) else Right(instance)
}
}
class NewPetValidation(instance: NewPet) {
import de.zalando.play.controllers.PlayValidations._
val allValidations = Seq.empty[scala.Either[scala.Seq[ParsingError], String]]
val result = {
val errors = allValidations.filter(_.isLeft).flatMap(_.left.get)
if (errors.nonEmpty) Left(errors) else Right(instance)
}
}
class ErrorValidation(instance: Error) {
import de.zalando.play.controllers.PlayValidations._
val allValidations = Seq.empty[scala.Either[scala.Seq[ParsingError], String]]
val result = {
val errors = allValidations.filter(_.isLeft).flatMap(_.left.get)
if (errors.nonEmpty) Left(errors) else Right(instance)
}
}

49. Validations
/pets/{id}:
get:
description: Returns a user based
on a single ID, if the user does not
have access to the pet
operationId: find pet by id
parameters:
- name: id
in: path
description: ID of pet to fetch
required: true
type: integer
format: int64
responses:
200:
description: pet response
schema:
$ref: '#/definitions/Pet'
default:
description: unexpected error
schema:
$ref: '#/definitions/Error'
class ValidationForPetexpandedYamlfindPetById(in: (Long)) {
val (id) = in
val idConstraints = new ValidationBase[Long] {
override def constraints: Seq[Constraint[Long]] = Seq()
}
val normalValidations =
Seq(idConstraints.applyConstraints(id))
val containerValidations =
Seq.empty[scala.Either[scala.Seq[ParsingError], String]]
val rightResult = Right((id))
val allValidations = normalValidations ++
containerValidations
val result = {
val errors =
allValidations.filter(_.isLeft).flatMap(_.left.get)
if (errors.nonEmpty) Left(errors) else rightResult
}
}

50. Tests
"discard invalid data" in new WithApplication {
val genInputs =
for {
id <- arbitrary[Long]
} yield (id)
val inputs = genInputs suchThat { i => new ValidationForPetexpandedYamlfindPetById(i).result !=
Right(i) }
val props = forAll(inputs) { i => testInvalidInput(i) }
checkResult(props)
}

51. Tests
def testInvalidInput(in: (Long)) = {
val (id) = in
val url = s"""/api/pets/${id}"""
val path = route(FakeRequest(GET, url)).get
val validation = new ValidationForPetexpandedYamlfindPetById(id).result
lazy val validations = validation.left.get flatMap {
_.messages map { m => contentAsString(path).contains(m) ?= true }
}
("given an URL: [" + url + "]") |: all(
status(path) ?= BAD_REQUEST,
contentType(path) ?= Some("application/json"),
validation.isLeft ?= true,
all(validations:_*)
)
}

52. Controllers
private val findPetByIdResponseMimeType = "application/json"
private val findPetByIdActionSuccessStatus = Status(200)
private type findPetByIdActionRequestType = (Long)
private type findPetByIdActionResultType = Pet
private type findPetByIdActionType = findPetByIdActionRequestType => Either[Throwable, findPetByIdActionResultType]
private def errorToStatusfindPetById: PartialFunction[Throwable, Status] = PartialFunction.empty[Throwable, Status]
def findPetByIdAction = (f: findPetByIdActionType) => (id: Long) => Action {
val result = new ValidationForPetexpandedYamlfindPetById(id).result.right.map {
processValidfindPetByIdRequest(f)
}
implicit val marshaller = parsingErrors2Writable(findPetByIdResponseMimeType)
val response = result.left.map { BadRequest(_) }
response.fold(a => a, c => c)
}
private def processValidfindPetByIdRequest(f: findPetByIdActionType)(request: findPetByIdActionRequestType) = {
val callerResult = f(request)
val status = callerResult match {
case Left(error) => (errorToStatusfindPetById orElse defaultErrorMapping)(error)
case Right(result) => findPetByIdActionSuccessStatus
}
implicit val findPetByIdWritableJson = anyToWritable[findPetByIdActionResultType](findPetByIdResponseMimeType)
status(callerResult)
}

53. Skeletons
class PetexpandedYaml extends PetexpandedYamlBase {
// handler for GET /pets
def findPets = findPetsAction { in : (Option[Seq[String]], Option[Int]) =>
val (tags, limit) = in
???
}
// handler for POST /pets
def addPet = addPetAction { in : (NewPet) =>
val (pet) = in
???
}
// handler for GET /pets/{id}
def findPetById = findPetByIdAction { in : (Long) =>
val (id) = in
???
}
// handler for DELETE /pets/{id}
def deletePet = deletePetAction { in : (Long) =>
val (id) = in
???
}
}

54. http://github.com/zalando/play-swagger

55. Questions?