Моки и фикстуры

Подготовка и очистка после тестов

Простое приспособление: только метод

import org.scalatest.flatspec.AnyFlatSpec
import org.scalatest.matchers.should.Matchers

class StackSpec extends AnyFlatSpec with Matchers {
  def emptyStack(): scala.collection.mutable.Stack[Int] =
    scala.collection.mutable.Stack.empty[Int]

  "a stack" should "start empty" in {
    emptyStack().size shouldBe 0
  }
}

BeforeAndAfter

import org.scalatest.flatspec.AnyFlatSpec
import org.scalatest.matchers.should.Matchers
import org.scalatest.BeforeAndAfter

class DbSpec extends AnyFlatSpec with Matchers with BeforeAndAfter {
  var counter = 0
  before { counter = 10 }
  after  { counter = 0 }

  "counter" should "be initialized" in {
    counter shouldBe 10
  }
}

BeforeAndAfterAll

import org.scalatest.flatspec.AnyFlatSpec
import org.scalatest.BeforeAndAfterAll

class ServerSpec extends AnyFlatSpec with BeforeAndAfterAll {
  override def beforeAll(): Unit = println("start server")
  override def afterAll(): Unit  = println("stop server")

  "server" should "respond" in {
    assert(true)
  }
}

Шаблон передачи ресурса

import org.scalatest.flatspec.AnyFlatSpec
import org.scalatest.matchers.should.Matchers

class FileSpec extends AnyFlatSpec with Matchers {
  def withBuffer(test: StringBuilder => Any): Unit = {
    val buf = new StringBuilder("init")
    try test(buf)
    finally buf.clear()
  }

  "a buffer" should "start with init" in withBuffer { buf =>
    buf.toString shouldBe "init"
  }
}

Зачем нужны имитации?

Добавление Mockito

libraryDependencies += "org.scalatestplus" %% "mockito-5-10" % "3.2.18.0" % Test

Задание поведения метода

import org.scalatest.flatspec.AnyFlatSpec
import org.scalatest.matchers.should.Matchers
import org.scalatestplus.mockito.MockitoSugar
import org.mockito.Mockito.when

trait Repo { def find(id: Int): String }

class RepoSpec extends AnyFlatSpec with Matchers with MockitoSugar {
  "a repo" should "return stubbed value" in {
    val repo = mock[Repo]
    when(repo.find(1)).thenReturn("Alice")
    repo.find(1) shouldBe "Alice"
  }
}

Проверка взаимодействий

import org.scalatest.flatspec.AnyFlatSpec
import org.scalatestplus.mockito.MockitoSugar
import org.mockito.Mockito.{verify, times}

trait Logger { def log(msg: String): Unit }

class LogSpec extends AnyFlatSpec with MockitoSugar {
  "a service" should "log once" in {
    val logger = mock[Logger]
    logger.log("hi")
    verify(logger, times(1)).log("hi")
  }
}

Имитации, заглушки и поддельные реализации

Сохранение изоляции тестов

Быстрая проверка

Итоги