Question

我有一个使用Cake模式的Scala应用程序：

trait RepositoryComponent {
  def repository: Repository

  trait Repository {
    def shouldSave(record: GenericRecord): Boolean
    def findRecord(keys: Array[String]): Long
    def insertRecord(record: GenericRecord)
    def updateRecord(keys: Array[String], record: GenericRecord)
    def cleanUp()
  }
}

trait DbRepositoryComponent extends RepositoryComponent with Logged {
  val connection: Connection
  val subscription: Subscription
  val schema: Schema

  def repository = new DbRepository(connection, subscription, schema)

  class DbRepository(connection: Connection, subscription: Subscription, schema: Schema) extends Repository {
    ...
  }

trait ConsumerComponent {
  def consumer: Consumer

  trait Consumer {
    def write(keys: Array[String], record: GenericRecord)
    def close()
  }
}

trait DbReplicatorComponent extends ConsumerComponent with Logged {
  this: RepositoryComponent =>

  def consumer = new DatabaseReplicator()

  class DatabaseReplicator extends Consumer {
    ...
  }

当我天真地开始测试consumer.write的实现时，我尝试了类似的东西（使用ScalaMock）：

class DbReplicatorComponentTests extends FunSuite with MockFactory {

  private val schema = new Schema.Parser().parse(getClass.getResourceAsStream("/AuditRecord.avsc"))
  private val record = new GenericRecordBuilder(schema)
    .set("id1", 123)
    .set("id2", "foo")
    .set("text", "blergh")
    .set("audit_fg", "I")
    .set("audit_ts", 1498770000L)
    .build()

  test("A record should be inserted if the audit flag is 'I' and no existing record is found") {
    val replicator = new DbReplicatorComponent with RepositoryComponent {
      override def repository: Repository = stub[Repository]
    }

    (replicator.repository.shouldSave _).when(record).returns(true)
    (replicator.repository.findRecord _).when(Array("123", "foo")).returns(0L)

    replicator.consumer.write(Array("123", "foo"), record)

    (replicator.repository.insertRecord _).verify(record)
  }
}

测试失败，因为我没有删除实际的实现：

Unsatisfied expectation:

Expected:
inAnyOrder {
  <stub-1> Repository.shouldSave({"id1": 123, "id2": "foo", "text": "blergh", "audit_fg": "I", "audit_ts": 1498770000}) any number of times (never called)
  <stub-2> Repository.findRecord([Ljava.lang.String;@4b8ee4de) any number of times (never called)
  <stub-4> Repository.insertRecord({"id1": 123, "id2": "foo", "text": "blergh", "audit_fg": "I", "audit_ts": 1498770000}) once (never called - UNSATISFIED)
}

Actual:
  <stub-3> Repository.shouldSave({"id1": 123, "id2": "foo", "text": "blergh", "audit_fg": "I", "audit_ts": 1498770000})
ScalaTestFailureLocation: com.generalmills.datalake.sql.DbReplicatorComponentTests at (DbReplicatorComponentTests.scala:12)
org.scalatest.exceptions.TestFailedException: Unsatisfied expectation:

这个问题凸显了我真的不喜欢Scala的事实。我不知道stub-3来自哪里。在this question之后我在damirv的回答中成功地重新测试了我的测试，但是我希望这里有一些见解可以帮助我更好地理解为什么我实际上并没有嘲笑我认为我在上面的测试吗

Fwiw，我是从C＃背景来到Scala。

更新：基于以下答案，这有效：

test("A record should be inserted if the audit flag is 'I' and no existing record is found") {
    val replicator = new DbReplicatorComponent with RepositoryComponent {
      val _repo = stub[Repository]
      override def repository: Repository = {
        _repo
      }
    }

    (replicator.repository.shouldSave _).when(record).returns(true)
    (replicator.repository.findRecord _).when(Array("123", "foo")).returns(0L)

    replicator.consumer.write(Array("123", "foo"), record)

    (replicator.repository.insertRecord _).verify(record)
  }

Answer 1

def repository: Repository这是一种每次调用时返回新存根的方法。尝试将其设为val，以便在每次调用/访问时返回相同的存根：

test("A record should be inserted if the audit flag is 'I' and no existing record is found") {
  val replicator = new DbReplicatorComponent with RepositoryComponent {
    override val repository: Repository = stub[Repository]
  }
  // ...
}

此外，您正在使用Array作为参数类型。请注意scala中的Array("foo") != Array("foo")，因此我建议您在使用数组argThat）的when调用中使用findRecord匹配器 - 请参阅此处：Unable to create stub with Array argument in ScalMock

或尝试Predicate Matching，如下所述：http://scalamock.org/user-guide/matching/

ScalaMock和Cake Pattern - 为什么我的存根没被调用？

1 个答案: