feat: add genesis simulation generation for ics27 (#2154)

## 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.

- [x] Targeted PR against correct branch (see [CONTRIBUTING.md](https://github.com/cosmos/ibc-go/blob/master/CONTRIBUTING.md#pr-targeting))
- [x] 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

CHANGELOG.md

@@ -71,6 +71,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 
 ### Improvements
 
+* (27-interchain-accounts) [\#1352](https://github.com/cosmos/ibc-go/issues/1352) Add support for Cosmos-SDK simulation to ics27 module.  
 * (apps/27-interchain-accounts) [\#2133](https://github.com/cosmos/ibc-go/pull/2133) Generates genesis protos in a separate directory to avoid circular import errors. The protobuf package name has changed for the genesis types. 
 * (linting) [\#1418](https://github.com/cosmos/ibc-go/pull/1418) Fix linting errors, resulting compatiblity with go1.18 linting style, golangci-lint 1.46.2 and the revivie linter.  This caused breaking changes in core/04-channel, core/ante, and the testing library.
 * (modules/light-clients/07-tendermint) [\#1713](https://github.com/cosmos/ibc-go/pull/1713) Allow client upgrade proposals to update `TrustingPeriod`. See ADR-026 for context.

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

@@ -10,6 +10,7 @@ import (
 	codectypes "github.com/cosmos/cosmos-sdk/codec/types"
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	"github.com/cosmos/cosmos-sdk/types/module"
+	simtypes "github.com/cosmos/cosmos-sdk/types/simulation"
 	"github.com/grpc-ecosystem/grpc-gateway/runtime"
 	"github.com/spf13/cobra"
 	abci "github.com/tendermint/tendermint/abci/types"
@@ -203,6 +204,21 @@ func (am AppModule) EndBlock(ctx sdk.Context, req abci.RequestEndBlock) []abci.V
 
 // AppModuleSimulation functions
 
+// GenerateGenesisState creates a randomized GenState of the ics27 module.
+func (AppModule) GenerateGenesisState(simState *module.SimulationState) {
+	simulation.RandomizedGenState(simState)
+}
+
+// ProposalContents doesn't return any content functions for governance proposals.
+func (AppModule) ProposalContents(_ module.SimulationState) []simtypes.WeightedProposalContent {
+	return nil
+}
+
+// WeightedOperations is unimplemented.
+func (am AppModule) WeightedOperations(_ module.SimulationState) []simtypes.WeightedOperation {
+	return nil
+}
+
 // 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/genesis.go

@@ -0,0 +1,70 @@
+package simulation
+
+import (
+	"encoding/json"
+	"fmt"
+	"math/rand"
+
+	"github.com/cosmos/cosmos-sdk/types/module"
+
+	controllertypes "github.com/cosmos/ibc-go/v5/modules/apps/27-interchain-accounts/controller/types"
+	genesistypes "github.com/cosmos/ibc-go/v5/modules/apps/27-interchain-accounts/genesis/types"
+	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/types"
+)
+
+// RandomEnabled randomized controller or host enabled param with 75% prob of being true.
+func RandomEnabled(r *rand.Rand) bool {
+	return r.Int63n(101) <= 75
+}
+
+// RandomizedGenState generates a random GenesisState for ics27.
+// Only the params are non nil
+func RandomizedGenState(simState *module.SimulationState) {
+	var controllerEnabled bool
+	simState.AppParams.GetOrGenerate(
+		simState.Cdc, string(controllertypes.KeyControllerEnabled), &controllerEnabled, simState.Rand,
+		func(r *rand.Rand) { controllerEnabled = RandomEnabled(r) },
+	)
+
+	controllerParams := controllertypes.Params{
+		ControllerEnabled: controllerEnabled,
+	}
+
+	controllerGenesisState := genesistypes.ControllerGenesisState{
+		ActiveChannels:     nil,
+		InterchainAccounts: nil,
+		Ports:              []string{},
+		Params:             controllerParams,
+	}
+
+	var hostEnabled bool
+	simState.AppParams.GetOrGenerate(
+		simState.Cdc, string(hosttypes.KeyHostEnabled), &hostEnabled, simState.Rand,
+		func(r *rand.Rand) { hostEnabled = RandomEnabled(r) },
+	)
+
+	hostParams := hosttypes.Params{
+		HostEnabled:   hostEnabled,
+		AllowMessages: []string{"*"}, // allow all messages
+	}
+
+	hostGenesisState := genesistypes.HostGenesisState{
+		ActiveChannels:     nil,
+		InterchainAccounts: nil,
+		Port:               types.PortID,
+		Params:             hostParams,
+	}
+
+	icaGenesis := genesistypes.GenesisState{
+		ControllerGenesisState: controllerGenesisState,
+		HostGenesisState:       hostGenesisState,
+	}
+
+	bz, err := json.MarshalIndent(&icaGenesis, "", " ")
+	if err != nil {
+		panic(err)
+	}
+	fmt.Printf("Selected randomly generated %s parameters:\n%s\n", types.ModuleName, bz)
+	simState.GenState[types.ModuleName] = simState.Cdc.MustMarshalJSON(&icaGenesis)
+}

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

@@ -0,0 +1,56 @@
+package simulation_test
+
+import (
+	"encoding/json"
+	"math/rand"
+	"testing"
+
+	"cosmossdk.io/math"
+	"github.com/cosmos/cosmos-sdk/codec"
+	codectypes "github.com/cosmos/cosmos-sdk/codec/types"
+	cryptocodec "github.com/cosmos/cosmos-sdk/crypto/codec"
+	"github.com/cosmos/cosmos-sdk/types/module"
+	simtypes "github.com/cosmos/cosmos-sdk/types/simulation"
+	"github.com/stretchr/testify/require"
+
+	genesistypes "github.com/cosmos/ibc-go/v5/modules/apps/27-interchain-accounts/genesis/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"
+)
+
+// TestRandomizedGenState tests the normal scenario of applying RandomizedGenState.
+// Abonormal scenarios are not tested here.
+func TestRandomizedGenState(t *testing.T) {
+	interfaceRegistry := codectypes.NewInterfaceRegistry()
+	cryptocodec.RegisterInterfaces(interfaceRegistry)
+	cdc := codec.NewProtoCodec(interfaceRegistry)
+
+	s := rand.NewSource(1) // 1 is the seed
+	r := rand.New(s)
+
+	simState := module.SimulationState{
+		AppParams:    make(simtypes.AppParams),
+		Cdc:          cdc,
+		Rand:         r,
+		NumBonded:    3,
+		Accounts:     simtypes.RandomAccounts(r, 3),
+		InitialStake: math.NewInt(1000),
+		GenState:     make(map[string]json.RawMessage),
+	}
+
+	simulation.RandomizedGenState(&simState)
+
+	var icaGenesis genesistypes.GenesisState
+	simState.Cdc.MustUnmarshalJSON(simState.GenState[types.ModuleName], &icaGenesis)
+
+	require.True(t, icaGenesis.ControllerGenesisState.Params.ControllerEnabled)
+	require.Empty(t, icaGenesis.ControllerGenesisState.ActiveChannels)
+	require.Empty(t, icaGenesis.ControllerGenesisState.InterchainAccounts)
+	require.Empty(t, icaGenesis.ControllerGenesisState.Ports)
+
+	require.True(t, icaGenesis.HostGenesisState.Params.HostEnabled)
+	require.Equal(t, []string{"*"}, icaGenesis.HostGenesisState.Params.AllowMessages)
+	require.Equal(t, types.PortID, icaGenesis.HostGenesisState.Port)
+	require.Empty(t, icaGenesis.ControllerGenesisState.ActiveChannels)
+	require.Empty(t, icaGenesis.ControllerGenesisState.InterchainAccounts)
+}