core: support NumChains change for BA modules (#339)

3 files changed, 17 insertions, 4 deletions

diff --git a/core/test/app.go b/core/test/app.go
index a5d0270..e67d5c9 100644
--- a/core/test/app.go
+++ b/core/test/app.go
@@ -198,6 +198,9 @@ func (app *App) GetLatestDeliveredPosition() types.Position {
 	defer app.deliveredLock.RUnlock()
 	app.blocksLock.RLock()
 	defer app.blocksLock.RUnlock()
+	if len(app.DeliverSequence) == 0 {
+		return types.Position{}
+	}
 	return app.blocks[app.DeliverSequence[len(app.DeliverSequence)-1]].Position
 }
 
diff --git a/core/test/governance.go b/core/test/governance.go
index f96e9e7..14c8177 100644
--- a/core/test/governance.go
+++ b/core/test/governance.go
@@ -33,6 +33,9 @@ import (
 	typesDKG "github.com/dexon-foundation/dexon-consensus/core/types/dkg"
 )
 
+// TODO(mission): add a method to compare config/crs between governance
+//                instances.
+
 // Governance is an implementation of Goverance for testing purpose.
 type Governance struct {
 	roundShift           uint64
@@ -105,6 +108,13 @@ func (g *Governance) NotifyRoundHeight(round, height uint64) {
 	func() {
 		g.lock.Lock()
 		defer g.lock.Unlock()
+		// Check if there is any pending changes for previous rounds.
+		for r := range g.pendingConfigChanges {
+			if r < shiftedRound+1 {
+				panic(fmt.Errorf("pending change no longer applied: %v, now: %v",
+					r, shiftedRound+1))
+			}
+		}
 		for t, v := range g.pendingConfigChanges[shiftedRound+1] {
 			if err := g.stateModule.RequestChange(t, v); err != nil {
 				panic(err)
@@ -346,7 +356,7 @@ func (g *Governance) RegisterConfigChange(
 	}
 	g.lock.Lock()
 	defer g.lock.Unlock()
-	if round <= uint64(len(g.configs)) {
+	if round < uint64(len(g.configs)) {
 		return errors.New(
 			"attempt to register state change for prepared rounds")
 	}
diff --git a/core/test/governance_test.go b/core/test/governance_test.go
index 07b0d46..01993f9 100644
--- a/core/test/governance_test.go
+++ b/core/test/governance_test.go
@@ -77,13 +77,13 @@ func (s *GovernanceTestSuite) TestRegisterChange() {
 	req.Equal(g.Configuration(4).NumChains, uint32(20))
 	// Unable to register change for prepared round.
 	req.Error(g.RegisterConfigChange(4, StateChangeNumChains, uint32(32)))
-	// Unable to register change for next notified round.
-	req.Error(g.RegisterConfigChange(5, StateChangeNumChains, uint32(32)))
 	// It's ok to make some change when condition is met.
+	req.NoError(g.RegisterConfigChange(5, StateChangeNumChains, uint32(32)))
 	req.NoError(g.RegisterConfigChange(6, StateChangeNumChains, uint32(32)))
 	req.NoError(g.RegisterConfigChange(7, StateChangeNumChains, uint32(40)))
 	// In local mode, state for round 6 would be ready after notified with
-	// round 5.
+	// round 2.
+	g.NotifyRoundHeight(2, 0)
 	g.NotifyRoundHeight(3, 0)
 	// In local mode, state for round 7 would be ready after notified with
 	// round 6.