如何模拟一个uuid生成器，该生成器针对不同的调用返回不同的值？

Question

I have a uuid generator, like:

class NewUuid {
    def apply: String = UUID.randomUUID().toString.replace("-", "")
}

And other class can use it:

class Dialog {
    val newUuid = new NewUuid
    def newButtons(): Seq[Button] = Seq(new Button(newUuid()), new Button(newUuid()))
}

Now I want to test the Dialog and mock the newUuid :

val dialog = new Dialog {
    val newUuid = mock[NewUuid]
    newUuid.apply returns "uuid1"
}
dialog.newButtons().map(_.text) === Seq("uuid1", "uuid1")

You can see the returned uuid is always uuid1 .

Is it possible to let newUuid to return different values for different calls? eg The first call returns uuid1 , the second returns uuid2 , etc

Answer 1

newUuid.apply returns "uudi1" thenReturns "uuid2"

https://etorreborre.github.io/specs2/guide/SPECS2-3.5/org.specs2.guide.UseMockito.html

Answer 2

Use an iterator to produce your UUIDs

def newUuid() = UUID.randomUUID().toString.replace("-", "")

val defaultUuidSource = Iterator continually newUuid()

class Dialog(uuids: Iterator[String] = defaultUuidSource) {
  def newButtons() = Seq(
    Button(uuids.next()),
    Button(uuids.next())
  )
}

Then provide a different one for testing:

val testUuidSource = Iterator from 1 map {"uuid" + _}
new Dialog(testUuidSource)