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When unit testing, what is the best approach to mocking out Akka Streams calls involving Sources, Flows and Sinks?

For example, the takeWhile function:

def takeWhile(p: Out => Boolean): Repr[Out]

Where Repr is a trait within a trait:

trait FlowOps[+Out, +Mat] {
  import akka.stream.impl.Stages._
  import GraphDSL.Implicits._

  type Repr[+O] <: FlowOps[O, Mat] {
    type Repr[+OO] = FlowOps.this.Repr[OO]
    type Closed = FlowOps.this.Closed
  }

If an object under test calls something like: mySource.takeWhile( ... ).runWith( ... ) I might need to mock it out...

How do you work out how to mock out, e.g., mock[Source[Any, Any]].takeWhile(*) returns mock[?]

The interactions between Source, Repr, FlowOps, and Out are unclear to me.

The source code for the FlowOps trait warns that it is internal and that one should not derive from it...does this affect mocking it?

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1 回答 1

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使用 Akka Streams 组件进行基本测试不需要模拟任何东西；只需使用testkit。如需灵感，请查看Akka 存储库中的测试。以下是来自的示例FlowTakeWhileSpec：

"take while predicate is true" in assertAllStagesStopped {
  Source(1 to 4).takeWhile(_ < 3).runWith(TestSink.probe[Int]).request(3).expectNext(1, 2).expectComplete()
}
于 2019-10-21T20:02:42.973 回答