PM-3146: Test MessageStash.

metronome/hotstuff/service/test/src/io/iohk/metronome/hotstuff/service/ConsensusServiceSpec.scala

@@ -0,0 +1,121 @@
+package io.iohk.metronome.hotstuff.service
+
+import io.iohk.metronome.hotstuff.consensus.basic.Agreement
+import monix.eval.Task
+import monix.execution.Scheduler.Implicits.global
+import org.scalatest.compatible.Assertion
+import org.scalatest.flatspec.AsyncFlatSpec
+import scala.concurrent.duration._
+import org.scalatest.matchers.should.Matchers
+import io.iohk.metronome.hotstuff.consensus.basic.{
+  ProtocolError,
+  Event,
+  Message,
+  Phase,
+  QuorumCertificate
+}
+import io.iohk.metronome.hotstuff.consensus.ViewNumber
+import io.iohk.metronome.crypto.GroupSignature
+
+class ConsensusServiceSpec extends AsyncFlatSpec with Matchers {
+  import ConsensusService.MessageStash
+
+  def testT[T](t: Task[Assertion]) =
+    t.timeout(10.seconds).runToFuture
+
+  def test(t: => Assertion) =
+    testT(Task(t))
+
+  object TestAgreement extends Agreement {
+    override type Block = Nothing
+    override type Hash  = Int
+    override type PSig  = Nothing
+    override type GSig  = Int
+    override type PKey  = String
+    override type SKey  = Nothing
+  }
+  type TestAgreement = TestAgreement.type
+
+  "MessageStash" should behave like {
+
+    val emptyStash = MessageStash.empty[TestAgreement]
+
+    val error = ProtocolError.TooEarly[TestAgreement](
+      Event.MessageReceived[TestAgreement](
+        "Alice",
+        Message.NewView(
+          ViewNumber(10),
+          QuorumCertificate[TestAgreement](
+            Phase.Prepare,
+            ViewNumber(9),
+            123,
+            GroupSignature(456)
+          )
+        )
+      ),
+      expectedInViewNumber = ViewNumber(11),
+      expectedInPhase = Phase.Prepare
+    )
+    val errorSlotKey = (error.expectedInViewNumber, error.expectedInPhase)
+
+    it should "stash errors" in test {
+      emptyStash.slots shouldBe empty
+
+      val stash = emptyStash.stash(error)
+
+      stash.slots should contain key errorSlotKey
+      stash.slots(errorSlotKey) should contain key error.event.sender
+      stash.slots(errorSlotKey)(error.event.sender) shouldBe error.event.message
+    }
+
+    it should "stash only the last message from a sender" in test {
+      val error2 = error.copy(event =
+        error.event.copy(message =
+          Message.NewView(
+            ViewNumber(10),
+            QuorumCertificate[TestAgreement](
+              Phase.Prepare,
+              ViewNumber(8),
+              122,
+              GroupSignature(455)
+            )
+          )
+        )
+      )
+      val stash = emptyStash.stash(error).stash(error2)
+
+      stash.slots(errorSlotKey)(
+        error.event.sender
+      ) shouldBe error2.event.message
+    }
+
+    it should "unstash due errors" in test {
+      val errors = List(
+        error,
+        error.copy(
+          expectedInPhase = Phase.PreCommit
+        ),
+        error.copy(
+          expectedInViewNumber = error.expectedInViewNumber.next
+        ),
+        error.copy(
+          expectedInViewNumber = error.expectedInViewNumber.next,
+          expectedInPhase = Phase.Commit
+        ),
+        error.copy(
+          expectedInViewNumber = error.expectedInViewNumber.next.next
+        )
+      )
+
+      val stash0 = errors.foldLeft(emptyStash)(_ stash _)
+
+      val (stash1, unstashed) = stash0.unstash(
+        errors(2).expectedInViewNumber,
+        errors(2).expectedInPhase
+      )
+
+      stash1.slots.keySet should have size 2
+      unstashed should have size 3
+    }
+  }
+}