go/oasis-test-runner: Fix e2e/consensus-state-sync scenario

Instead of terminating the validator-to-be-synced immediately and restarting
it later, do not even start it. Early stopping could result in state that
prevents proper state sync later.

.changelog/3194.internal.md

@@ -0,0 +1,5 @@
+go/oasis-test-runner: Fix e2e/consensus-state-sync scenario
+
+Instead of terminating the validator-to-be-synced immediately and restarting
+it later, do not even start it. Early stopping could result in state that
+prevents proper state sync later.

go/oasis-test-runner/scenario/e2e/consensus_state_sync.go

@@ -40,7 +40,7 @@ func (sc *consensusStateSyncImpl) Fixture() (*oasis.NetworkFixture, error) {
 	f.Network.Consensus.Parameters.StateCheckpointChunkSize = 1024 * 1024
 	// Add an extra validator.
 	f.Validators = append(f.Validators,
-		oasis.ValidatorFixture{Entity: 1, Consensus: oasis.ConsensusFixture{EnableConsensusRPCWorker: true}},
+		oasis.ValidatorFixture{NoAutoStart: true, Entity: 1, Consensus: oasis.ConsensusFixture{EnableConsensusRPCWorker: true}},
 	)
 
 	return f, nil
@@ -53,16 +53,10 @@ func (sc *consensusStateSyncImpl) Run(childEnv *env.Env) error {
 
 	sc.Logger.Info("waiting for network to come up")
 	ctx := context.Background()
-	if err := sc.Net.Controller().WaitNodesRegistered(ctx, len(sc.Net.Validators())); err != nil {
+	if err := sc.Net.Controller().WaitNodesRegistered(ctx, len(sc.Net.Validators())-1); err != nil {
 		return err
 	}
 
-	// Stop one of the validators.
-	val := sc.Net.Validators()[2]
-	if err := val.Stop(); err != nil {
-		return fmt.Errorf("failed to stop validator: %w", err)
-	}
-
 	// Let the network run for 50 blocks. This should generate some checkpoints.
 	blockCh, blockSub, err := sc.Net.Controller().Consensus.WatchBlocks(ctx)
 	if err != nil {
@@ -85,7 +79,7 @@ func (sc *consensusStateSyncImpl) Run(childEnv *env.Env) error {
 		break
 	}
 
-	sc.Logger.Info("got some blocks, starting the validator back",
+	sc.Logger.Info("got some blocks, starting the validator that needs to sync",
 		"trust_height", blk.Height,
 		"trust_hash", hex.EncodeToString(blk.Hash),
 	)
@@ -122,14 +116,15 @@ func (sc *consensusStateSyncImpl) Run(childEnv *env.Env) error {
 	}
 
 	// Configure state sync for the consensus validator.
+	val := sc.Net.Validators()[2]
 	val.SetConsensusStateSync(&oasis.ConsensusStateSyncCfg{
 		ConsensusNodes: consensusNodes,
 		TrustHeight:    uint64(blk.Height),
 		TrustHash:      hex.EncodeToString(blk.Hash),
 	})
 
 	if err = val.Start(); err != nil {
-		return fmt.Errorf("failed to start validator back: %w", err)
+		return fmt.Errorf("failed to start validator: %w", err)
 	}
 
 	// Wait for the validator to finish syncing.