ScalaMock 和蛋糕模式 - 为什么我的存根没有被调用?

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，我尝试了这样的事情(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，因为我没有存根实际实现：

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:

这个问题突出了我真的不了解Scala的事实。我不知道存根 3 是从哪里来的。我已经成功地按照 damirv 在这个问题上的回答重新设计了我的测试，但我在这里希望有一些见解来帮助我更好地理解为什么我实际上没有嘲笑我认为我在上面的测试中是什么？

Fwiw，我从C#背景来到Scala。

更新：根据下面的答案，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

这是一个每次调用时都会返回新存根的方法。尝试将其设置为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，您正在使用数组作为参数类型。请注意，Array("foo") != Array("foo")scala 中，所以我建议您在when调用中使用argThat匹配器，其中使用 Array (findRecord( - 请参阅此处：无法在 ScalMock 中使用 Array 参数创建存根

或者尝试谓词匹配，如下所述：http://scalamock.org/user-guide/matching/