Our path to integration testing on Scala project using Play! framework, ScalaTest and MongoDB.

1. INTEGRATION TESTING
WITH SCALATEST,
MONGODB AND PLAY!
EXPERIENCE FROM PLAY! PROJECT
By /Michal Bigos @teliatko

2. AGENDA
1. Integration testing, why and when
2. ScalaTest for integration testing with MongoDB and Play!
3. Custom DSL for integration testing and small extensions to
Casbah

3. CONTEXT
FROM WHERE THIS ALL CAME FROM...
Social network application with mobile clients
Build on top of Play! 2
Core API = REST services
MongoDB used as main persistent store
Hosted on Heroku
Currently in beta

4. INTEGRATION TESTING, WHY AND WHEN?
PART ONE

5. DEFINITION
Wikipedia:
“ The phase in software testing in which
individual software modules are combined
and tested as a group. ”

6. ANOTHER ONE :)
Arquillian:
“ Testing business components, in particular,
can be very challenging. Often, a vanilla unit
test isn't sufficient for validating such a
component's behavior. Why is that? The
reason is that components in an enterprise
application rarely perform operations which
are strictly self-contained. Instead, they
interact with or provide services for the
greater system. ”

7. UNIT TESTS 'VS' INTEGRATION TESTS
UNIT TESTS PROPERTIES:
Isolated - Checking one single concern in the system. Usually
behavior of one class.
Repeateable - It can be rerun as meny times as you want.
Consistent - Every run gets the same results.
Fast - Because there are loooot of them.

8. UNIT TESTS 'VS' INTEGRATION TESTS
UNIT TESTS TECHNIQUES:
Mocking
Stubing
xUnit frameworks
Fixtures in code

9. UNIT TESTS 'VS' INTEGRATION TESTS
INTEGRATION TESTS PROPERTIES:
Not isolated - Do not check the component or class itself, but
rather integrated components together (sometimes whole
application).
Slow - Depend on the tested component/sub-system.

10. UNIT TESTS 'VS' INTEGRATION TESTS
VARIOUS INTEGRATION TESTS TYPES:
Data-driven tests - Use real data and persistent store.
In-container tests - Simulates real container deployment,
e.g. JEE one.
Performance tests - Simulate traffic growth.
Acceptance tests - Simulate use cases from user point of
view.

11. UNIT TESTS 'VS' INTEGRATION TESTS
KNOWN FRAMEWORKS:
Data-driven tests - DBUnit, NoSQL Unit...
In-container tests - Arquillian...
Performance tests - JMeter...
Acceptance tests - Selenium, Cucumber...

12. WHY AND WHEN ?
WHAT CANNOT BE WRITTEN/SIMULATED IN UNIT TEST
Interaction with resources or sub-systems provided by
container.
Interaction with external systems.
Usage of declarative services applied to component at
runtime.
Testing whole scenarions in one test.
Architectural constraints limits isolation.

13. OUR CASE
ARCHITECTURAL CONSTRAINTS LIMITING ISOLATION:
Lack of DI
Controller depends directly on DAO
object CheckIns extends Controller {
...
def generate(pubId: String) = Secured.withBasic { caller: User =>
Action { implicit request =>
val pubOpt = PubDao.findOneById(pubId)
...
}
}
}
object PubDao extends SalatDAO[Pub, ObjectId](MongoDBSetup.mongoDB("pubs
")) {
...
}

15. OUR CASE
DEPENDENCIES BETWEEN COMPONENTS:

16. OUR CASE
GOALS:
Integration tests with real DAOs and DB
Writing them like unit tests

17. SCALATEST FOR INTEGRATION TESTING WITH
MONGODB AND PLAY!
PART TWO

18. TESTING STRATEGY
Responsibility - encapsulate domain logic
Unit test - testing the correctness of domain logic

19. TESTING STRATEGY
Responsibility - read/save model
Integration test - testing the correctness of queries and
modifications, with real data and DB

20. TESTING STRATEGY
Responsibility - serialize/deserialize model to JSON
Integration test - testing the correctness of JSON output,
using the real DAOs

21. TESTING FRAMEWORKS
SCALATEST
Standalone xUnit framework
Can be used within JUnit, TestNG...
Pretty DSLs for writing test, especially FreeSpec
Personal preference over specs2
Hooks for integration testing BeforeAndAfterand
BeforeAndAfterAlltraits

22. TESTING FRAMEWORKS
PLAY!'S TESTING SUPPORT
Fake application
Real HTTP server
it should "Test something dependent on Play! application" in {
running(FakeApplication()) {
// Do something which depends on Play! application
}
}
"run in a server" in {
running(TestServer(3333)) {
await(WS.url("http://localhost:3333").get).status must equalTo(OK)
}
}

23. TESTING FRAMEWORKS
DATA-DRIVEN TESTS FOR MONGODB
- Mock implementation of the MongoDB
protocol and works purely in-memory.
- More general library for testing with various
NoSQL stores. It can provide mocked or real MongoDB
instance. Relies on JUnit rules.
- Platform independent way of running local
MongoDB instances.
jmockmongo
NoSQL Unit
EmbedMongo

24. APPLICATION CODE
Configuration of MongoDB in application
... another object
trait MongoDBSetup {
val MONGODB_URL = "mongoDB.url"
val MONGODB_PORT = "mongoDB.port"
val MONGODB_DB = "mongoDB.db"
}
object MongoDBSetup extends MongoDBSetup {
private[this] val conf = current.configuration
val url = conf.getString(MONGODB_URL).getOrElse(...)
val port = conf.getInt(MONGODB_PORT).getOrElse(...)
val db = conf.getString(MONGODB_DB).getOrElse(...)
val mongoDB = MongoConnection(url, port)(db)
}

25. APPLICATION CODE
Use of MongoDBSetupin DAOs
We have to mock or provide real DB to test the DAO
object PubDao extends SalatDAO[Pub, ObjectId](MongoDBSetup.mongoDB("pubs
")) {
...
}

26. APPLICATION CODE
Controllers
... you've seen this already
object CheckIns extends Controller {
...
def generate(pubId: String) = Secured.withBasic { caller: User =>
Action { implicit request =>
val pubOpt = PubDao.findOneById(pubId)
...
}
}
}

27. OUR SOLUTION
Embedding * to ScalaTestembedmongo
trait EmbedMongoDB extends BeforeAndAfterAll { this: BeforeAndAfterAll with Suite =>
def embedConnectionURL: String = { "localhost" }
def embedConnectionPort: Int = { 12345 }
def embedMongoDBVersion: Version = { Version.V2_2_1 }
def embedDB: String = { "test" }
lazy val runtime: MongodStarter = MongodStarter.getDefaultInstance
lazy val mongodExe: MongodExecutable = runtime.prepare(new MongodConfig(embedMongoDBV
ersion, embedConnectionPort, true))
lazy val mongod: MongodProcess = mongodExe.start()
override def beforeAll() {
mongod
super.beforeAll()
}
override def afterAll() {
super.afterAll()
mongod.stop(); mongodExe.stop()
}
lazy val mongoDB = MongoConnection(embedConnectionURL, embedConnectionPort)(embedDB)
}

28. *we love recursion in Scala isn't it?

29. OUR SOLUTION
Custom fake application
Trait configures fake application instance for embedded
MongoDB instance. MongoDBSetupconsumes this values.
trait FakeApplicationForMongoDB extends MongoDBSetup { this: EmbedMongoDB =>
lazy val fakeApplicationWithMongo = FakeApplication(additionalConfiguration = Map(
MONGODB_PORT -> embedConnectionPort.toString,
MONGODB_URL -> embedConnectionURL,
MONGODB_DB -> embedDB
))
}

30. OUR SOLUTION
Typical test suite class
class DataDrivenMongoDBTest extends FlatSpec
with ShouldMatchers
with MustMatchers
with EmbedMongoDB
with FakeApplicationForMongoDB {
...
}

31. OUR SOLUTION
Test method which uses mongoDBinstance directly
it should "Save and read an Object to/from MongoDB" in {
// Given
val users = mongoDB("users") // this is from EmbedMongoDB trait
// When
val user = User(username = username, password = password)
users += grater[User].asDBObject(user)
// Then
users.count should equal (1L)
val query = MongoDBObject("username" -> username)
users.findOne(query).map(grater[User].asObject(_)) must equal (Some(user))
// Clean-up
users.dropCollection()
}

32. OUR SOLUTION
Test method which uses DAO via
fakeApplicationWithMongo
it should "Save and read an Object to/from MongoDB which is used in application" in {
running(fakeApplicationWithMongo) {
// Given
val user = User(username = username, password = password)
// When
UserDao.save(user)
// Then
UserDao.findAll().find(_ == user) must equal (Some(user))
}
}

33. OUR SOLUTION
Example of the full test from controller down to model
class FullWSTest extends FlatSpec with ShouldMatchers with MustMatchers with EmbedMongo
DB with FakeApplicationForMongoDB {
val username = "test"
val password = "secret"
val userJson = """{"id":"%s","firstName":"","lastName":"","age":-1,"gender":-1,"state
":"notFriends","photoUrl":""}"""
"Detail method" should "return correct Json for User" in {
running(TestServer(3333, fakeApplicationWithMongo)) {
val users = mongoDB("users")
val user = User(username = username, password = md5(username + password))
users += grater[User].asDBObject(user)
val userId = user.id.toString
val response = await(WS.url("http://localhost:3333/api/user/" + userId)
.withAuth(username, password, AuthScheme.BASIC)
.get())
response.status must equal (OK)
response.header("Content-Type") must be (Some("application/json; charset=utf-8"))
response.body must include (userJson.format(userId))
}
}

34. }

35. CUSTOM DSL FOR INTEGRATION TESTING AND
SMALL EXTENSIONS TO CASBAH
PART THREE
WORK IN PROGRESS

36. MORE DATA
Creating a simple data is easy, but what about collections...
We need easy way to seed them from prepared source and
check them afterwards.

37. CUSTOM DSL FOR SEEDING THE DATA
Principle
Seed the data before test
Use them in test ... read, create or modify
Check them after test (optional)

38. CUSTOM DSL FOR SEEDING THE DATA
Inspiration - ,
Based on JUnit rules or verbose code
NoSQL Unit DBUnit
public class WhenANewBookIsCreated {
@ClassRule
public static ManagedMongoDb managedMongoDb = newManagedMongoDbRule().mongodPath("/
opt/mongo").build();
@Rule
public MongoDbRule remoteMongoDbRule = new MongoDbRule(mongoDb().databaseName("test
").build());
@Test
@UsingDataSet(locations="initialData.json", loadStrategy=LoadStrategyEnum.CLEAN_INS
ERT)
@ShouldMatchDataSet(location="expectedData.json")
public void book_should_be_inserted_into_repository() {
...
}
}

39. This is Java. Example is taken from NoSQL Unit documentation.

40. CUSTOM DSL FOR SEEDING THE DATA
Goals
Pure functional solution
Better fit with ScalaTest
JUnit independent

41. CUSTOM DSL FOR SEEDING THE DATA
Result
it should "Load all Objcts from MongoDB" in {
mongoDB seed ("users") fromFile ("./database/data/users.json") and
seed ("pubs") fromFile ("./database/data/pubs.json")
cleanUpAfter {
running(fakeApplicationWithMongo) {
val users = UserDao.findAll()
users.size must equal (10)
}
}
// Probably will be deprecated in next versions
mongoDB seed ("users") fromFile ("./database/data/users.json") now()
running(fakeApplicationWithMongo) {
val users = UserDao.findAll()
users.size must equal (10)
}
mongoDB cleanUp ("users")
}

42. CUSTOM DSL FOR SEEDING THE DATA
Already implemented
Seeding, clean-up and clean-up after for functional and
non-funtional usage.
JSON fileformat similar to NoSQL Unit - difference, per
collection basis.

43. CUSTOM DSL FOR SEEDING THE DATA
Still in pipeline
Checking against dataset, similar to
@ShouldMatchDataSet annotation of NoSQL Unit.
JS file format of mongoexport. Our biggest problem here
are Dates (proprietary format).
JS file format with full JavaScript functionality of mongo
command. To be able to run commands like:
db.pubs.ensureIndex({loc : "2d"})
NoSQL Unit JSON file format with multiple collections and
seeding more collections in once.

44. TOPPING
SMALL ADDITIONS TO CASBAH FOR BETTER QUERY SYNTAX
We don't like this*
... I cannot read it, can't you?
* and when possible we don't write this
def findCheckInsBetweenDatesInPub(
pubId: String,
dateFrom: LocalDateTime,
dateTo: LocalDateTime) : List[CheckIn] = {
val query = MongoDBObject("pubId" -> new ObjectId(pubId), "created" ->
MongoDBObject("$gte" -> dateFrom, "$lt" -> dateTo))
collection.find(query).map(grater[CheckIn].asObject(_)).toList.headOpt
ion
}

45. TOPPING
SMALL ADDITIONS TO CASBAH FOR BETTER QUERY SYNTAX
We like pretty code a lot ... like this:
Casbah query DSL is our favorite ... even when it is not
perfect
def findBetweenDatesForPub(pubId: ObjectId, from: DateTime, to: DateTime
) : List[CheckIn] = {
find {
("pubId" -> pubId) ++
("created" $gte from $lt to)
} sort {
("created" -> -1)
}
}.toList.headOption

46. TOPPING
SMALL ADDITIONS TO CASBAH FOR BETTER QUERY SYNTAX
So we enhanced it:
def findBetweenDatesForPub(pubId: ObjectId, from: DateTime, to: DateTime
) : List[CheckIn] = {
find {
("pubId" $eq pubId) ++
("created" $gte from $lt to)
} sort {
"created" $eq -1
}
}.headOption

47. TOPPING
SMALL ADDITIONS TO CASBAH FOR BETTER QUERY
Pimp my library again and again...
// Adds $eq operator instead of ->
implicit def queryOperatorAdditions(field: String) = new {
protected val _field = field
} with EqualsOp
trait EqualsOp {
protected def _field: String
def $eq[T](target: T) = MongoDBObject(_field -> target)
}
// Adds Scala collection headOption operation to SalatCursor
implicit def cursorAdditions[T <: AnyRef](cursor: SalatMongoCursor[T]) = new {
protected val _cursor = cursor
} with CursorOperations[T]
trait CursorOperations[T <: AnyRef] {
protected def _cursor: SalatMongoCursor[T]
def headOption : Option[T] = if (_cursor.hasNext) Some(_cursor.next()) else None
}

48. THANKS FOR YOUR ATTENTION