Minor refactor: factor out Begin(End)Block calls from simibc (#588)

* Factors out BeginBlock, EndBlock calls

* Adds comments

* Adds docstring to BeginBlock

Co-authored-by: Daniel <[email protected]>
Co-authored-by: Marius Poke <[email protected]>

testutil/simibc/chain_util.go

@@ -0,0 +1,59 @@
+package simibc
+
+import (
+	"time"
+
+	channelkeeper "github.com/cosmos/ibc-go/v3/modules/core/04-channel/keeper"
+	channeltypes "github.com/cosmos/ibc-go/v3/modules/core/04-channel/types"
+	ibctmtypes "github.com/cosmos/ibc-go/v3/modules/light-clients/07-tendermint/types"
+	ibctesting "github.com/cosmos/ibc-go/v3/testing"
+	abci "github.com/tendermint/tendermint/abci/types"
+	tmproto "github.com/tendermint/tendermint/proto/tendermint/types"
+)
+
+// BeginBlock updates the current header and calls the app.BeginBlock() method.
+// The new block height is the previous block height + 1.
+// The new block time is the previous block time + dt.
+func BeginBlock(c *ibctesting.TestChain, dt time.Duration) {
+
+	c.CurrentHeader = tmproto.Header{
+		ChainID:            c.ChainID,
+		Height:             c.App.LastBlockHeight() + 1,
+		AppHash:            c.App.LastCommitID().Hash,
+		Time:               c.CurrentHeader.Time.Add(dt),
+		ValidatorsHash:     c.Vals.Hash(),
+		NextValidatorsHash: c.NextVals.Hash(),
+	}
+
+	_ = c.App.BeginBlock(abci.RequestBeginBlock{Header: c.CurrentHeader})
+}
+
+// EndBlock and calls the preCommitCallback before the app.Commit() is called.
+func EndBlock(c *ibctesting.TestChain, preCommitCallback func()) (*ibctmtypes.Header, []channeltypes.Packet) {
+	ebRes := c.App.EndBlock(abci.RequestEndBlock{Height: c.CurrentHeader.Height})
+
+	/*
+		It is useful to call arbitrary code after ending the block but before
+		committing the block because the sdk.Context is cleared after committing.
+	*/
+	preCommitCallback()
+
+	c.App.Commit()
+
+	c.Vals = c.NextVals
+
+	c.NextVals = ibctesting.ApplyValSetChanges(c.T, c.Vals, ebRes.ValidatorUpdates)
+
+	c.LastHeader = c.CurrentTMClientHeader()
+
+	packets := []channeltypes.Packet{}
+
+	for _, e := range ebRes.Events {
+		if e.Type == channeltypes.EventTypeSendPacket {
+			packet, _ := channelkeeper.ReconstructPacketFromEvent(e)
+			packets = append(packets, packet)
+		}
+	}
+
+	return c.LastHeader, packets
+}

testutil/simibc/relayed_path.go

@@ -5,12 +5,8 @@ import (
 
 	"testing"
 
-	channelkeeper "github.com/cosmos/ibc-go/v3/modules/core/04-channel/keeper"
-	channeltypes "github.com/cosmos/ibc-go/v3/modules/core/04-channel/types"
 	ibctmtypes "github.com/cosmos/ibc-go/v3/modules/light-clients/07-tendermint/types"
 	ibctesting "github.com/cosmos/ibc-go/v3/testing"
-	abci "github.com/tendermint/tendermint/abci/types"
-	tmproto "github.com/tendermint/tendermint/proto/tendermint/types"
 )
 
 // RelayedPath augments ibctesting.Path, giving fine-grained control
@@ -92,44 +88,13 @@ func (f *RelayedPath) DeliverAcks(chainID string, num int) {
 // allowing access to the sdk.Context after EndBlock.
 func (f *RelayedPath) EndAndBeginBlock(chainID string, dt time.Duration, preCommitCallback func()) {
 	c := f.Chain(chainID)
-
-	ebRes := c.App.EndBlock(abci.RequestEndBlock{Height: c.CurrentHeader.Height})
-
-	preCommitCallback()
-
-	c.App.Commit()
-
-	c.Vals = c.NextVals
-
-	c.NextVals = ibctesting.ApplyValSetChanges(c.T, c.Vals, ebRes.ValidatorUpdates)
-
-	c.LastHeader = c.CurrentTMClientHeader()
-
-	// Store header to be used in UpdateClient
-	f.clientHeaders[chainID] = append(f.clientHeaders[chainID], c.LastHeader)
-
-	for _, e := range ebRes.Events {
-		if e.Type == channeltypes.EventTypeSendPacket {
-			packet, _ := channelkeeper.ReconstructPacketFromEvent(e)
-			// Collect packets
-			f.Link.AddPacket(chainID, packet)
-		}
+	header, packets := EndBlock(c, preCommitCallback)
+	f.clientHeaders[chainID] = append(f.clientHeaders[chainID], header)
+	for _, p := range packets {
+		f.Link.AddPacket(chainID, p)
 	}
-
-	// Commit packets emmitted up to this point
 	f.Link.Commit(chainID)
-
-	// increment the current header
-	c.CurrentHeader = tmproto.Header{
-		ChainID:            c.ChainID,
-		Height:             c.App.LastBlockHeight() + 1,
-		AppHash:            c.App.LastCommitID().Hash,
-		Time:               c.CurrentHeader.Time.Add(dt),
-		ValidatorsHash:     c.Vals.Hash(),
-		NextValidatorsHash: c.NextVals.Hash(),
-	}
-
-	_ = c.App.BeginBlock(abci.RequestBeginBlock{Header: c.CurrentHeader})
+	BeginBlock(c, dt)
 }
 
 func (f *RelayedPath) other(chainID string) string {