diff --git a/client/tx/tx.go b/client/tx/tx.go
index dca9787c2a..a3ead89d66 100644
--- a/client/tx/tx.go
+++ b/client/tx/tx.go
@@ -191,7 +191,7 @@ func BuildUnsignedTx(txf Factory, msgs ...sdk.Msg) (ClientTx, error) {
 	tx.SetFee(auth.NewStdFee(txf.gas, fees))
 	tx.SetMsgs(msgs...)
 	tx.SetMemo(txf.memo)
-	tx.SetSignatures(nil)
+	tx.SetSignatures()
 
 	return tx, nil
 }
diff --git a/client/tx/tx_test.go b/client/tx/tx_test.go
new file mode 100644
index 0000000000..55688dba7e
--- /dev/null
+++ b/client/tx/tx_test.go
@@ -0,0 +1,106 @@
+package tx_test
+
+import (
+	"encoding/json"
+	"errors"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"github.com/cosmos/cosmos-sdk/client/tx"
+	"github.com/cosmos/cosmos-sdk/codec/std"
+	sdk "github.com/cosmos/cosmos-sdk/types"
+	"github.com/cosmos/cosmos-sdk/x/auth"
+	"github.com/cosmos/cosmos-sdk/x/bank"
+)
+
+func TestCalculateGas(t *testing.T) {
+	makeQueryFunc := func(gasUsed uint64, wantErr bool) func(string, []byte) ([]byte, int64, error) {
+		return func(string, []byte) ([]byte, int64, error) {
+			if wantErr {
+				return nil, 0, errors.New("query failed")
+			}
+			simRes := sdk.SimulationResponse{
+				GasInfo: sdk.GasInfo{GasUsed: gasUsed, GasWanted: gasUsed},
+				Result:  &sdk.Result{Data: []byte("tx data"), Log: "log"},
+			}
+
+			bz, err := json.Marshal(simRes)
+			if err != nil {
+				return nil, 0, err
+			}
+
+			return bz, 0, nil
+		}
+	}
+
+	type args struct {
+		queryFuncGasUsed uint64
+		queryFuncWantErr bool
+		adjustment       float64
+	}
+
+	testCases := []struct {
+		name         string
+		args         args
+		wantEstimate uint64
+		wantAdjusted uint64
+		expPass      bool
+	}{
+		{"error", args{0, true, 1.2}, 0, 0, false},
+		{"adjusted gas", args{10, false, 1.2}, 10, 12, true},
+	}
+
+	for _, tc := range testCases {
+		stc := tc
+
+		t.Run(stc.name, func(t *testing.T) {
+			queryFunc := makeQueryFunc(stc.args.queryFuncGasUsed, stc.args.queryFuncWantErr)
+			simRes, gotAdjusted, err := tx.CalculateGas(queryFunc, []byte(""), stc.args.adjustment)
+			if stc.expPass {
+				require.NoError(t, err)
+				require.Equal(t, simRes.GasInfo.GasUsed, stc.wantEstimate)
+				require.Equal(t, gotAdjusted, stc.wantAdjusted)
+				require.NotNil(t, simRes.Result)
+			} else {
+				require.Error(t, err)
+				require.Nil(t, simRes.Result)
+			}
+		})
+	}
+}
+
+func TestBuildSimTx(t *testing.T) {
+	txf := tx.Factory{}.
+		WithTxGenerator(std.TxGenerator{}).
+		WithAccountNumber(50).
+		WithSequence(23).
+		WithFees("50stake").
+		WithMemo("memo").
+		WithChainID("test-chain")
+
+	msg := bank.NewMsgSend(sdk.AccAddress("from"), sdk.AccAddress("to"), nil)
+	bz, err := tx.BuildSimTx(txf, msg)
+	require.NoError(t, err)
+	require.NotNil(t, bz)
+
+	tx := &std.Transaction{}
+	require.NoError(t, tx.Unmarshal(bz))
+	require.Equal(t, []sdk.Signature{sdk.Signature(auth.StdSignature{})}, tx.GetSignatures())
+}
+
+func TestBuildUnsignedTx(t *testing.T) {
+	txf := tx.Factory{}.
+		WithTxGenerator(std.TxGenerator{}).
+		WithAccountNumber(50).
+		WithSequence(23).
+		WithFees("50stake").
+		WithMemo("memo").
+		WithChainID("test-chain")
+
+	msg := bank.NewMsgSend(sdk.AccAddress("from"), sdk.AccAddress("to"), nil)
+	tx, err := tx.BuildUnsignedTx(txf, msg)
+	require.NoError(t, err)
+	require.NotNil(t, tx)
+	require.Equal(t, []sdk.Signature{}, tx.GetSignatures())
+}