feat: add decoder store to ics27 simulations (#2158) (#2164)

## Description

ref: #1352, #2151

---

Before we can merge this PR, please make sure that all the following items have been
checked off. If any of the checklist items are not applicable, please leave them but
write a little note why.

- [ ] Targeted PR against correct branch (see [CONTRIBUTING.md](https://github.com/cosmos/ibc-go/blob/master/CONTRIBUTING.md#pr-targeting))
- [ ] Linked to Github issue with discussion and accepted design OR link to spec that describes this work.
- [ ] Code follows the [module structure standards](https://github.com/cosmos/cosmos-sdk/blob/master/docs/building-modules/structure.md).
- [ ] Wrote unit and integration [tests](https://github.com/cosmos/ibc-go/blob/master/CONTRIBUTING.md#testing)
- [ ] Updated relevant documentation (`docs/`) or specification (`x/<module>/spec/`)
- [ ] Added relevant `godoc` [comments](https://blog.golang.org/godoc-documenting-go-code).
- [ ] Added a relevant changelog entry to the `Unreleased` section in `CHANGELOG.md`
- [ ] Re-reviewed `Files changed` in the Github PR explorer
- [ ] Review `Codecov Report` in the comment section below once CI passes

(cherry picked from commit 23a7515)

Co-authored-by: colin axnér <25233464+colin-axner@users.noreply.github.com>

modules/apps/27-interchain-accounts/module.go

@@ -21,6 +21,7 @@ import (
 	"github.com/cosmos/ibc-go/v5/modules/apps/27-interchain-accounts/host"
 	hostkeeper "github.com/cosmos/ibc-go/v5/modules/apps/27-interchain-accounts/host/keeper"
 	hosttypes "github.com/cosmos/ibc-go/v5/modules/apps/27-interchain-accounts/host/types"
+	"github.com/cosmos/ibc-go/v5/modules/apps/27-interchain-accounts/simulation"
 	"github.com/cosmos/ibc-go/v5/modules/apps/27-interchain-accounts/types"
 	porttypes "github.com/cosmos/ibc-go/v5/modules/core/05-port/types"
 	ibchost "github.com/cosmos/ibc-go/v5/modules/core/24-host"
@@ -199,3 +200,10 @@ func (am AppModule) BeginBlock(ctx sdk.Context, req abci.RequestBeginBlock) {
 func (am AppModule) EndBlock(ctx sdk.Context, req abci.RequestEndBlock) []abci.ValidatorUpdate {
 	return []abci.ValidatorUpdate{}
 }
+
+// AppModuleSimulation functions
+
+// RegisterStoreDecoder registers a decoder for interchain accounts module's types
+func (am AppModule) RegisterStoreDecoder(sdr sdk.StoreDecoderRegistry) {
+	sdr[types.StoreKey] = simulation.NewDecodeStore()
+}

modules/apps/27-interchain-accounts/simulation/decoder.go

@@ -0,0 +1,28 @@
+package simulation
+
+import (
+	"bytes"
+	"fmt"
+
+	"github.com/cosmos/cosmos-sdk/types/kv"
+
+	"github.com/cosmos/ibc-go/v5/modules/apps/27-interchain-accounts/types"
+)
+
+// NewDecodeStore returns a decoder function closure that unmarshals the KVPair's
+// Value to the corresponding DenomTrace type.
+func NewDecodeStore() func(kvA, kvB kv.Pair) string {
+	return func(kvA, kvB kv.Pair) string {
+		switch {
+		case bytes.Equal(kvA.Key[:len(types.PortKeyPrefix)], []byte(types.PortKeyPrefix)):
+			return fmt.Sprintf("Port A: %s\nPort B: %s", string(kvA.Value), string(kvB.Value))
+		case bytes.Equal(kvA.Key[:len(types.OwnerKeyPrefix)], []byte(types.OwnerKeyPrefix)):
+			return fmt.Sprintf("Owner A: %s\nOwner B: %s", string(kvA.Value), string(kvB.Value))
+		case bytes.Equal(kvA.Key[:len(types.ActiveChannelKeyPrefix)], []byte(types.ActiveChannelKeyPrefix)):
+			return fmt.Sprintf("ActiveChannel A: %s\nActiveChannel B: %s", string(kvA.Value), string(kvB.Value))
+
+		default:
+			panic(fmt.Sprintf("invalid %s key prefix %s", types.ModuleName, kvA.Key))
+		}
+	}
+}

modules/apps/27-interchain-accounts/simulation/decoder_test.go

@@ -0,0 +1,59 @@
+package simulation_test
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/cosmos/cosmos-sdk/types/kv"
+	"github.com/stretchr/testify/require"
+
+	"github.com/cosmos/ibc-go/v5/modules/apps/27-interchain-accounts/simulation"
+	"github.com/cosmos/ibc-go/v5/modules/apps/27-interchain-accounts/types"
+	ibctesting "github.com/cosmos/ibc-go/v5/testing"
+)
+
+func TestDecodeStore(t *testing.T) {
+	var (
+		owner     = "owner"
+		channelID = ibctesting.FirstChannelID
+	)
+
+	dec := simulation.NewDecodeStore()
+
+	kvPairs := kv.Pairs{
+		Pairs: []kv.Pair{
+			{
+				Key:   []byte(types.PortKeyPrefix),
+				Value: []byte(types.PortID),
+			},
+			{
+				Key:   []byte(types.OwnerKeyPrefix),
+				Value: []byte("owner"),
+			},
+			{
+				Key:   []byte(types.ActiveChannelKeyPrefix),
+				Value: []byte("channel-0"),
+			},
+		},
+	}
+	tests := []struct {
+		name        string
+		expectedLog string
+	}{
+		{"PortID", fmt.Sprintf("Port A: %s\nPort B: %s", types.PortID, types.PortID)},
+		{"Owner", fmt.Sprintf("Owner A: %s\nOwner B: %s", owner, owner)},
+		{"ActiveChannel", fmt.Sprintf("ActiveChannel A: %s\nActiveChannel B: %s", channelID, channelID)},
+		{"other", ""},
+	}
+
+	for i, tt := range tests {
+		i, tt := i, tt
+		t.Run(tt.name, func(t *testing.T) {
+			if i == len(tests)-1 {
+				require.Panics(t, func() { dec(kvPairs.Pairs[i], kvPairs.Pairs[i]) }, tt.name)
+			} else {
+				require.Equal(t, tt.expectedLog, dec(kvPairs.Pairs[i], kvPairs.Pairs[i]), tt.name)
+			}
+		})
+	}
+}