ante: add ValidateMemoDecorator evm tx (#150)

fixes #149

app/ante/ante.go

@@ -64,6 +64,7 @@ func NewAnteHandler(
 						authante.NewMempoolFeeDecorator(),
 						authante.NewValidateBasicDecorator(),
 						authante.TxTimeoutHeightDecorator{},
+						authante.NewValidateMemoDecorator(ak),
 						NewEthSigVerificationDecorator(evmKeeper),
 						NewEthAccountVerificationDecorator(ak, bankKeeper, evmKeeper),
 						NewEthNonceVerificationDecorator(ak),

app/ante/ante_test.go

@@ -2,6 +2,7 @@ package ante_test
 
 import (
 	"math/big"
+	"strings"
 
 	sdk "github.com/cosmos/cosmos-sdk/types"
 
@@ -91,6 +92,17 @@ func (suite AnteTestSuite) TestAnteHandler() {
 				return tx
 			}, false, true, true,
 		},
+		{
+			"fail - CheckTx (memo too long)",
+			func() sdk.Tx {
+				signedTx := evmtypes.NewMsgEthereumTx(suite.app.EvmKeeper.ChainID(), 3, &to, big.NewInt(10), 100000, big.NewInt(1), nil, nil)
+				signedTx.From = addr.Hex()
+
+				txBuilder := suite.CreateTestTxBuilder(signedTx, privKey, 1)
+				txBuilder.SetMemo(strings.Repeat("*", 257))
+				return txBuilder.GetTx()
+			}, true, false, false,
+		},
 	}
 
 	for _, tc := range testCases {

app/ante/utils_test.go

@@ -73,6 +73,13 @@ func TestAnteTestSuite(t *testing.T) {
 func (suite *AnteTestSuite) CreateTestTx(
 	msg *evmtypes.MsgEthereumTx, priv cryptotypes.PrivKey, accNum uint64,
 ) authsigning.Tx {
+	return suite.CreateTestTxBuilder(msg, priv, accNum).GetTx()
+}
+
+// CreateTestTxBuilder is a helper function to create a tx builder given multiple inputs.
+func (suite *AnteTestSuite) CreateTestTxBuilder(
+	msg *evmtypes.MsgEthereumTx, priv cryptotypes.PrivKey, accNum uint64,
+) client.TxBuilder {
 
 	option, err := codectypes.NewAnyWithValue(&evmtypes.ExtensionOptionsEthereumTx{})
 	suite.Require().NoError(err)
@@ -125,7 +132,7 @@ func (suite *AnteTestSuite) CreateTestTx(
 	err = suite.txBuilder.SetSignatures(sigsV2...)
 	suite.Require().NoError(err)
 
-	return suite.txBuilder.GetTx()
+	return suite.txBuilder
 }
 
 func newTestAddrKey() (common.Address, cryptotypes.PrivKey) {