Fixed Simulator Can't get ParentSlot (#602)

validator/beacon/BUILD.bazel

@@ -25,6 +25,7 @@ go_test(
         "//proto/beacon/rpc/v1:go_default_library",
         "//shared/testutil:go_default_library",
         "//validator/internal:go_default_library",
+        "//validator/params:go_default_library",
         "@com_github_golang_mock//gomock:go_default_library",
         "@com_github_golang_protobuf//ptypes:go_default_library_gen",
         "@com_github_sirupsen_logrus//:go_default_library",

validator/beacon/service.go

@@ -135,7 +135,8 @@ func (s *Service) fetchCurrentAssignmentsAndGenesisTime(client pb.BeaconServiceC
 	for _, assign := range res.Assignments {
 		if bytes.Equal(assign.PublicKey.PublicKey, s.pubKey) {
 			s.role = assign.Role
-			s.assignedSlot = s.CurrentCycleStartSlot() + assign.AssignedSlot
+			// + 1 to account for the genesis block being slot 0.
+			s.assignedSlot = s.CurrentCycleStartSlot(params.DemoConfig().CycleLength) + assign.AssignedSlot + 1
 			s.shardID = assign.ShardId
 
 			log.Infof("Validator shuffled. Pub key 0x%s re-assigned to shard ID %d for %v duty at slot %d",
@@ -176,7 +177,12 @@ func (s *Service) listenForAssignmentChange(client pb.BeaconServiceClient) {
 		for _, assign := range assignment.Assignments {
 			if bytes.Equal(assign.PublicKey.PublicKey, s.pubKey) {
 				s.role = assign.Role
-				s.assignedSlot = s.CurrentCycleStartSlot() + assign.AssignedSlot
+				if s.CurrentCycleStartSlot(params.DemoConfig().CycleLength) == 0 {
+					// +1 to account for genesis block being slot 0.
+					s.assignedSlot = params.DemoConfig().CycleLength + assign.AssignedSlot + 1
+				} else {
+					s.assignedSlot = s.CurrentCycleStartSlot(params.DemoConfig().CycleLength) + assign.AssignedSlot + 1
+				}
 				s.shardID = assign.ShardId
 
 				log.Infof("Validator with pub key 0x%s re-assigned to shard ID %d for %v duty at slot %d",
@@ -280,12 +286,15 @@ func (s *Service) PublicKey() []byte {
 // CurrentBeaconSlot based on the genesis timestamp of the protocol.
 func (s *Service) CurrentBeaconSlot() uint64 {
 	secondsSinceGenesis := time.Since(s.genesisTimestamp).Seconds()
-	return uint64(math.Floor(secondsSinceGenesis / params.DefaultConfig().SlotDuration))
+	if secondsSinceGenesis-params.DefaultConfig().SlotDuration < 0 {
+		return 0
+	}
+	return uint64(math.Floor(secondsSinceGenesis/params.DefaultConfig().SlotDuration)) - 1
 }
 
 // CurrentCycleStartSlot returns the slot at which the current cycle started.
-func (s *Service) CurrentCycleStartSlot() uint64 {
+func (s *Service) CurrentCycleStartSlot(cycleLength uint64) uint64 {
 	currentSlot := s.CurrentBeaconSlot()
-	cycleNum := math.Floor(float64(currentSlot) / float64(params.DefaultConfig().CycleLength))
-	return uint64(cycleNum) * params.DefaultConfig().CycleLength
+	cycleNum := currentSlot / cycleLength
+	return uint64(cycleNum) * cycleLength
 }

validator/beacon/service_test.go

@@ -16,6 +16,7 @@ import (
 	pb "github.com/prysmaticlabs/prysm/proto/beacon/rpc/v1"
 	"github.com/prysmaticlabs/prysm/shared/testutil"
 	"github.com/prysmaticlabs/prysm/validator/internal"
+	"github.com/prysmaticlabs/prysm/validator/params"
 	"github.com/sirupsen/logrus"
 	logTest "github.com/sirupsen/logrus/hooks/test"
 )
@@ -301,7 +302,7 @@ func TestListenForAssignmentProposer(t *testing.T) {
 	stream := internal.NewMockBeaconService_ValidatorAssignmentsClient(ctrl)
 
 	// Testing proposer assignment.
-	assignedSlot := b.CurrentCycleStartSlot() + 2
+	assignedSlot := b.CurrentCycleStartSlot(params.DefaultConfig().CycleLength) + 2
 	stream.EXPECT().Recv().Return(&pb.ValidatorAssignmentResponse{Assignments: []*pb.Assignment{{
 		PublicKey:    &pb.PublicKey{PublicKey: []byte{'A'}},
 		ShardId:      2,

validator/params/config.go

@@ -16,6 +16,14 @@ func DefaultConfig() *Config {
 	}
 }
 
+// DemoConfig for running the system under shorter defaults.
+func DemoConfig() *Config {
+	return &Config{
+		SlotDuration: 8.0,
+		CycleLength:  5,
+	}
+}
+
 // DefaultCollationSizeLimit is the integer value representing the maximum
 // number of bytes allowed in a given collation.
 func DefaultCollationSizeLimit() int64 {