Testing in Scala by Adform research
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This document provides an overview of different types of software tests including unit tests, integration tests, functional tests, and acceptance tests. It also discusses test-driven development (TDD) and behavior-driven development (BDD). Some key points: - Unit tests check specific functionality in isolation and use mocking. Integration tests check component integration using real dependencies. Functional tests use real data to test functionality. Acceptance tests are final tests performed by clients. - TDD involves writing tests first as an interface/trait before implementation. BDD is similar but focuses on defining behavior. - ScalaTest is a common Scala testing framework that supports different styles like FunSuite, WordSpec. It allows mocking,
![Using ScalaTest
import org.scalatest.FunSuite
class SetSuite extends FunSuite {
test("An empty Set should have size 0") {
assert(Set.empty.size == 0)
}
test("Invoking head on an empty Set should produce NoSuchElementException") {
intercept[NoSuchElementException] {
Set.empty.head
}
}
}](https://image.slidesharecdn.com/testing-150306052315-conversion-gate01/85/Testing-in-Scala-by-Adform-research-13-320.jpg)
![Matchers
β’ ScalaTest has lots of syntactic sugar to express your desires
result should equal (3)
result should have size 10
string should fullyMatch regex """(-)?(d+)(.d*)?"""
result1 should not be an [Orangutan]
sevenDotOh should equal (6.9 +- 0.2)
"howdy" should contain oneOf ('a', 'b', 'c', 'd')
(Array("Doe", "Ray", "Me") should contain oneOf ("X", "RAY", "BEAM")) (after being lowerCased)
List(0, 1, 2, 2, 99, 3, 3, 3, 5) should contain inOrder (1, 2, 3)
map should (contain key ("two") and not contain value (7))
This is Scala Code !!](https://image.slidesharecdn.com/testing-150306052315-conversion-gate01/85/Testing-in-Scala-by-Adform-research-25-320.jpg)
![Mocking
β’ You should always code against interfaces (traits)
β’ If you do, testing is easier, since you can mock your dependencies!
val m = mock[Turtle]
m.expects.forward(10.0) twice
m1 returns 42
m2 expects ("this", "that") returning "the other"](https://image.slidesharecdn.com/testing-150306052315-conversion-gate01/85/Testing-in-Scala-by-Adform-research-26-320.jpg)
![ScalaCheck
import org.scalacheck.Gen
val propConcatLists = forAll { (l1: List[Int], l2: List[Int]) =>
l1.size + l2.size == (l1 ::: l2).size
}
+ OK, passed 100 tests.
val propSqrt = forAll { (n: Int) => scala.math.sqrt(n*n) == n }
! Falsified after 1 passed tests:
> -1](https://image.slidesharecdn.com/testing-150306052315-conversion-gate01/85/Testing-in-Scala-by-Adform-research-28-320.jpg)
![ScalaCheck: Generators
val genLeaf = value(Leaf)
val genNode = for {
v <- arbitrary[Int]
left <- genTree
right <- genTree
} yield Node(left, right, v)
def genTree: Gen[Tree] = oneOf(genLeaf, genNode)
Option[Tree] = Some(Node(Leaf,Node(Node(Node(Node(Node(Node(Leaf,Leaf,-
71),Node(Leaf,Leaf,-49),17),Leaf,-20),Leaf,-7),Node(Node(Leaf,Leaf,26),Leaf,-
3),49),Leaf,84),-29))](https://image.slidesharecdn.com/testing-150306052315-conversion-gate01/85/Testing-in-Scala-by-Adform-research-29-320.jpg)
Testing in Scala by Adform research
- 2. Concepts: Types of Tests Technology Business GlobalLocal Unit Integration Functional Acceptance
- 3. Unit Tests β’ Check very specific functionality of your code β’ Assumes everything else works (mocking) β’ Test one specific/technical thing β’ e.g. test your Hadoop job locally, given money in DKK, currency conversion to EUR is called once
- 4. Integration Tests β’ Check that all components work together β’ Includes real components, databases, files, etc. β’ Test the connectivity of components β’ e.g. run a job on a development Hadoop cluster, given sample data expected output is written
- 5. Functional Tests β’ Test your product against the functionality you developed β’ Use real components, real data β’ E.g. run job on a live cluster, given a days worth of data the output is correct (as expected according to specification)
- 6. Acceptance Tests β’ Final tests performed by your client before βaccepting the productβ β’ Real components, real data, output is correct, performance is acceptable, client is happy
- 7. Concepts: Testing Styles β’ TDD: Test Driven Development β’ BDD: Behavior Driven Development
- 8. Test Driven Development β’ Write an interface (trait) for the behavior β’ Write an empty implementation β’ Write your unit tests β’ Make the code compile and tests fail β’ Correct the implementation β’ Make the tests pass !
- 9. Behavior Driven Development β’ Same idea, just write more functional tests (define behavior)
- 10. Testing in Scala β’ For every class in src/main/scala write a test class in src/test/scala β’ Test classes ~ Test suites β’ Methods ~ Tests β’ Run the suit and see the output
- 11. Testing Libraries/Frameworks β’ Java: JUnit, TestNG (can be used with scala) β’ Scala: ScalaTest, Specs2 β’ Mocking: ScalaMock, EasyMock, JMock, Mockito β’ Property Testing: ScalaCheck β’ UI Testing: Selenium
- 12. β’ Very similar to Specs2, maybe more flexible, mainly choice of taste β’ Integrates with sbt, IntelliJ β’ Integrates with Mockito, ScalaCheck libraryDependencies += "org.scalatest" %% "scalatest" % "2.2.1" % "test"
- 13. Using ScalaTest import org.scalatest.FunSuite class SetSuite extends FunSuite { test("An empty Set should have size 0") { assert(Set.empty.size == 0) } test("Invoking head on an empty Set should produce NoSuchElementException") { intercept[NoSuchElementException] { Set.empty.head } } }
- 17. Style Traits β’ ScalaTest allows you to mix in a testing style you like: β’ FunSuite β’ FlatSpec β’ FunSpec β’ WordSpec β’ PropSpec β’ etc. β’ http://www.scalatest.org/user_guide/selecting_a_style
- 18. FunSuite
- 19. FlatSpec
- 20. WordSpec
- 21. FeatureSpec
- 22. Testing Styles β’ ScalaTest recommends having an abstract class with the specs and other traits you like package com.mycompany.myproject import org.scalatest._ abstract class UnitSpec extends FlatSpec with Matchers with OptionValues with Inside with Inspectors package com.mycompany.myproject import org.scalatest._ class MySpec extends UnitSpec { // Your tests here }
- 23. Fixtures β’ Your tests may need some setting up and tearing down β’ ScalaTest has many ways of doing this β’ http://www.scalatest.org/user_guide/sharing_fixtures
- 25. Matchers β’ ScalaTest has lots of syntactic sugar to express your desires result should equal (3) result should have size 10 string should fullyMatch regex """(-)?(d+)(.d*)?""" result1 should not be an [Orangutan] sevenDotOh should equal (6.9 +- 0.2) "howdy" should contain oneOf ('a', 'b', 'c', 'd') (Array("Doe", "Ray", "Me") should contain oneOf ("X", "RAY", "BEAM")) (after being lowerCased) List(0, 1, 2, 2, 99, 3, 3, 3, 5) should contain inOrder (1, 2, 3) map should (contain key ("two") and not contain value (7)) This is Scala Code !!
- 26. Mocking β’ You should always code against interfaces (traits) β’ If you do, testing is easier, since you can mock your dependencies! val m = mock[Turtle] m.expects.forward(10.0) twice m1 returns 42 m2 expects ("this", "that") returning "the other"
- 27. Property Based Testing β’ New and exciting way of testing your code! β’ Instead of examples, you specify properties (higher order testing!) β’ E.g. when you concatenate two lists, new lengths is sum of lengths β’ ScalaCheck then generates random inputs and runs many tests β’ This can catch MANY corner cases you never expect!
- 28. ScalaCheck import org.scalacheck.Gen val propConcatLists = forAll { (l1: List[Int], l2: List[Int]) => l1.size + l2.size == (l1 ::: l2).size } + OK, passed 100 tests. val propSqrt = forAll { (n: Int) => scala.math.sqrt(n*n) == n } ! Falsified after 1 passed tests: > -1
- 29. ScalaCheck: Generators val genLeaf = value(Leaf) val genNode = for { v <- arbitrary[Int] left <- genTree right <- genTree } yield Node(left, right, v) def genTree: Gen[Tree] = oneOf(genLeaf, genNode) Option[Tree] = Some(Node(Leaf,Node(Node(Node(Node(Node(Node(Leaf,Leaf,- 71),Node(Leaf,Leaf,-49),17),Leaf,-20),Leaf,-7),Node(Node(Leaf,Leaf,26),Leaf,- 3),49),Leaf,84),-29))
- 30. is AWESOME !!
- 31. Scoverage β’ Produces test coverage reports β’ Measures how many statements are tested β’ Only works with Scala 2.11
- 33. Testing Scalding Jobs HOMEWORK: use ScalaTest instead of Specs2
- 34. DEMO TIME Slava takes the stage