scalatest-3.2.3 의 property based test

문제

https://wefree.tistory.com/77 의 property based test 를 scalatest-3.2.3 버전을 이용해 작성해 보자.

코드

build.sbt 에 scalatest, scalacheck 라이브러리를 추가한다.

libraryDependencies ++= Seq(
  "org.scalatest"  %% "scalatest"  % "3.2.3" % Test,
  "org.scalatestplus" %% "scalatestplus-scalacheck" % "3.1.0.0-RC2" % Test
)

테스트를 작성한다.

import org.scalacheck.Gen
import org.scalatest.BeforeAndAfter
import org.scalatest.funsuite.AnyFunSuite
import org.scalatestplus.scalacheck.ScalaCheckPropertyChecks

object Calculator {
  def lastDigit(n: Int): Int = math.abs(n) % 10
  def isDivisibleByFive(n: Int): Boolean = n % 5 == 0
}

class CalculatorTest extends AnyFunSuite with BeforeAndAfter with ScalaCheckPropertyChecks {
  test("lastDigit table test") {
    val table = Table(
      ("number", "lastDigit"), // First tuple defines column names
      (0, 0),
      (1, 1),
      (-1, 1),
      (12, 2),
      (-12, 2),
      (123, 3)
    )

    forAll(table)((number, last) => assert(Calculator.lastDigit(number) === last))
  }

  test("isDivisibleByFive property test") {
    forAll { x: Int =>
      whenever(x >= 0) {
        val last = Calculator.lastDigit(x)
        assert(Calculator.isDivisibleByFive(x) === (last == 0 || last == 5))
      }
    }
  }

  test("isDivisibleByFive Gen test") {
    val numbers: Gen[Int] = Gen.choose(-1000, 1000).map(_ * 3)

    forAll(numbers) { x: Int =>
      val last = Calculator.lastDigit(x)
      assert(Calculator.isDivisibleByFive(x) === (last == 0 || last == 5))
    }
  }
}