テスト駆動開発入門のxUnitをScalaで書いてみた

test.scala

package jp.ponko2.tddbook.xunit

object Main extends App {
  val suite = new TestSuite()
  suite.add(new TestCaseTest("testTemplateMethod"))
  suite.add(new TestCaseTest("testResult"))
  suite.add(new TestCaseTest("testFailedResult"))
  suite.add(new TestCaseTest("testFailedResultFormatting"))
  suite.add(new TestCaseTest("testSuite"))
  val result = new TestResult()
  suite.run(result)
  println(result.summary())
}

class TestCaseTest(name: String) extends TestCase(name) {
  var result: TestResult = _

  override def setUp() = {
    result = new TestResult()
  }

  def testTemplateMethod() = {
    val test = new WasRun("testMethod")
    test.run(result)
    assert("setUp testMethod tearDown " == test.log)
  }

  def testResult() = {
    val test = new WasRun("testMethod")
    test.run(result)
    assert("1 run, 0 failed" == result.summary())
  }

  def testFailedResult() = {
    val test = new WasRun("testBrokenMethod")
    test.run(result)
    assert("1 run, 1 failed" == result.summary())
  }

  def testFailedResultFormatting() = {
    result.testStarted()
    result.testFailed()
    assert("1 run, 1 failed" == result.summary())
  }

  def testSuite() = {
    val suite = new TestSuite()
    suite.add(new WasRun("testMethod"))
    suite.add(new WasRun("testBrokenMethod"))
    suite.run(result)
    assert("2 run, 1 failed" == result.summary())
  }
}

xUnit.scala

package jp.ponko2.tddbook.xunit

import scala.collection.mutable.ArrayBuffer

class TestCase(name: String) {
  def setUp() = {}

  def run(result: TestResult) = {
    result.testStarted()
    setUp()
    try {
      getClass.getMethod(name).invoke(this)
    } catch {
      case _ => result.testFailed()
    }
    tearDown()
    result
  }

  def tearDown() = {}
}

class TestResult() {
  var runCount = 0
  var errorCount = 0

  def testStarted() = {
    runCount += 1
  }

  def testFailed() = {
    errorCount += 1
  }

  def summary() = {
    "%d run, %d failed".format(runCount, errorCount)
  }
}

class TestSuite() {
  val tests = new ArrayBuffer[TestCase]

  def add(test: TestCase) = {
    tests += test
  }

  def run(result: TestResult) = {
    tests.foreach(_.run(result))
  }
}

class WasRun(name: String) extends TestCase(name) {
  var log: String = _

  override def setUp() = {
    log = "setUp "
  }

  def testMethod() = {
    log += "testMethod "
  }

  def testBrokenMethod() = {
    throw new Exception()
  }

  override def tearDown() = {
    log += "tearDown "
  }
}