Add custom message handler option

CHANGELOG.md

@@ -4,7 +4,8 @@
 
 [Full Changelog](https://github.com/CosmWasm/wasmd/compare/v0.15.0...HEAD)
 
-- Implement IBC contract support [\#394](https://github.com/CosmWasm/wasmd/pull/394)
+- Support custom MessageHandler [\#327](https://github.com/CosmWasm/wasmd/issues/327)
+- 🎉 Implement IBC contract support [\#394](https://github.com/CosmWasm/wasmd/pull/394)
 
 ## [v0.15.0](https://github.com/CosmWasm/wasmd/tree/v0.15.0) (2021-01-27)
 

x/wasm/internal/keeper/options.go

@@ -8,8 +8,17 @@ func (f optsFn) apply(keeper *Keeper) {
 	f(keeper)
 }
 
+// WithMessageHandler is an optional constructor parameter to replace the default wasm vm engine with the
+// given one.
 func WithWasmEngine(x types.WasmerEngine) Option {
 	return optsFn(func(k *Keeper) {
 		k.wasmer = x
 	})
 }
+
+// WithMessageHandler is an optional constructor parameter to set a custom message handler.
+func WithMessageHandler(n messenger) Option {
+	return optsFn(func(k *Keeper) {
+		k.messenger = n
+	})
+}

x/wasm/internal/keeper/options_test.go

@@ -0,0 +1,57 @@
+package keeper
+
+import (
+	"github.com/CosmWasm/wasmd/x/wasm/internal/keeper/wasmtesting"
+	"github.com/CosmWasm/wasmd/x/wasm/internal/types"
+	authkeeper "github.com/cosmos/cosmos-sdk/x/auth/keeper"
+	distributionkeeper "github.com/cosmos/cosmos-sdk/x/distribution/keeper"
+	paramtypes "github.com/cosmos/cosmos-sdk/x/params/types"
+	stakingkeeper "github.com/cosmos/cosmos-sdk/x/staking/keeper"
+	"github.com/stretchr/testify/assert"
+	"testing"
+)
+
+func TestConstructorOptions(t *testing.T) {
+	specs := map[string]struct {
+		srcOpt Option
+		verify func(Keeper)
+	}{
+		"wasm engine": {
+			srcOpt: WithWasmEngine(&wasmtesting.MockWasmer{}),
+			verify: func(k Keeper) {
+				assert.IsType(t, k.wasmer, &wasmtesting.MockWasmer{})
+			},
+		},
+		"message handler": {
+			srcOpt: WithMessageHandler(&wasmtesting.MockMessageHandler{}),
+			verify: func(k Keeper) {
+				assert.IsType(t, k.messenger, &wasmtesting.MockMessageHandler{})
+			},
+		},
+	}
+	for name, spec := range specs {
+		t.Run(name, func(t *testing.T) {
+			k := NewKeeper(
+				nil,
+				nil,
+				paramtypes.NewSubspace(nil, nil, nil, nil, ""),
+				authkeeper.AccountKeeper{},
+				nil,
+				stakingkeeper.Keeper{},
+				distributionkeeper.Keeper{},
+				nil,
+				nil,
+				nil,
+				nil,
+				"tempDir",
+				types.DefaultWasmConfig(),
+				"",
+				nil,
+				nil,
+				spec.srcOpt,
+			)
+			spec.verify(k)
+		})
+	}
+
+}