diff --git a/types/errors.go b/types/errors.go
index 5c96d8c241..48e08b1164 100644
--- a/types/errors.go
+++ b/types/errors.go
@@ -52,7 +52,7 @@ func CodeToDefaultMsg(code CodeType) string {
 	case CodeUnrecognizedAddress:
 		return "Unrecognized address"
 	case CodeInvalidPubKey:
-		return "Missing pubkey"
+		return "Invalid pubkey"
 	default:
 		return fmt.Sprintf("Unknown code %d", code)
 	}
diff --git a/types/tx_msg.go b/types/tx_msg.go
index b41d9879a9..21bc330540 100644
--- a/types/tx_msg.go
+++ b/types/tx_msg.go
@@ -146,3 +146,32 @@ func (msg StdSignMsg) Bytes() []byte {
 
 // Application function variable used to unmarshal transaction bytes
 type TxDecoder func(txBytes []byte) (Tx, Error)
+
+//__________________________________________________________
+
+var _ Msg = (*TestMsg)(nil)
+
+// msg type for testing
+type TestMsg struct {
+	signers []Address
+}
+
+func NewTestMsg(addrs ...Address) *TestMsg {
+	return &TestMsg{
+		signers: addrs,
+	}
+}
+
+func (msg *TestMsg) Type() string                            { return "TestMsg" }
+func (msg *TestMsg) Get(key interface{}) (value interface{}) { return nil }
+func (msg *TestMsg) GetSignBytes() []byte {
+	bz, err := json.Marshal(msg.signers)
+	if err != nil {
+		panic(err)
+	}
+	return bz
+}
+func (msg *TestMsg) ValidateBasic() Error { return nil }
+func (msg *TestMsg) GetSigners() []Address {
+	return msg.signers
+}
diff --git a/x/auth/ante.go b/x/auth/ante.go
index 2da0d92868..43b9bb8341 100644
--- a/x/auth/ante.go
+++ b/x/auth/ante.go
@@ -133,7 +133,9 @@ func processSig(
 	return
 }
 
-// deduct the fee from the account
+// Deduct the fee from the account.
+// We could use the CoinKeeper (in addition to the AccountMapper,
+// because the CoinKeeper doesn't give us accounts), but it seems easier to do this.
 func deductFees(acc sdk.Account, fee sdk.StdFee) (sdk.Account, sdk.Result) {
 	coins := acc.GetCoins()
 	feeAmount := fee.Amount
diff --git a/x/auth/ante_test.go b/x/auth/ante_test.go
index ecd2226230..5bbb3d0b69 100644
--- a/x/auth/ante_test.go
+++ b/x/auth/ante_test.go
@@ -1,7 +1,6 @@
 package auth
 
 import (
-	"encoding/json"
 	"testing"
 
 	sdk "github.com/cosmos/cosmos-sdk/types"
@@ -11,29 +10,8 @@ import (
 	crypto "github.com/tendermint/go-crypto"
 )
 
-// msg type for testing
-type testMsg struct {
-	signers []sdk.Address
-}
-
-func newTestMsg(addrs ...sdk.Address) *testMsg {
-	return &testMsg{
-		signers: addrs,
-	}
-}
-
-func (msg *testMsg) Type() string                            { return "testMsg" }
-func (msg *testMsg) Get(key interface{}) (value interface{}) { return nil }
-func (msg *testMsg) GetSignBytes() []byte {
-	bz, err := json.Marshal(msg.signers)
-	if err != nil {
-		panic(err)
-	}
-	return bz
-}
-func (msg *testMsg) ValidateBasic() sdk.Error { return nil }
-func (msg *testMsg) GetSigners() []sdk.Address {
-	return msg.signers
+func newTestMsg(addrs ...sdk.Address) *sdk.TestMsg {
+	return sdk.NewTestMsg(addrs...)
 }
 
 func newStdFee() sdk.StdFee {
@@ -246,6 +224,10 @@ func TestAnteHandlerBadSignBytes(t *testing.T) {
 	var tx sdk.Tx
 	msg := newTestMsg(addr1)
 	fee := newStdFee()
+	fee2 := newStdFee()
+	fee2.Gas += 100
+	fee3 := newStdFee()
+	fee3.Amount[0].Amount += 100
 
 	// test good tx and signBytes
 	privs, seqs := []crypto.PrivKey{priv1}, []int64{0}
@@ -253,6 +235,7 @@ func TestAnteHandlerBadSignBytes(t *testing.T) {
 	checkValidTx(t, anteHandler, ctx, tx)
 
 	chainID := ctx.ChainID()
+	chainID2 := chainID + "somemorestuff"
 	codeUnauth := sdk.CodeUnauthorized
 
 	cases := []struct {
@@ -262,9 +245,12 @@ func TestAnteHandlerBadSignBytes(t *testing.T) {
 		msg     sdk.Msg
 		code    sdk.CodeType
 	}{
-		{"", []int64{1}, fee, msg, codeUnauth},                    // test invalid chain_id
-		{chainID, []int64{2}, fee, msg, codeUnauth},               // test wrong seqs
-		{chainID, []int64{1}, fee, newTestMsg(addr2), codeUnauth}, // test wrong msg
+		{chainID2, []int64{1}, fee, msg, codeUnauth},               // test wrong chain_id
+		{chainID, []int64{2}, fee, msg, codeUnauth},                // test wrong seqs
+		{chainID, []int64{1, 2}, fee, msg, codeUnauth},             // test wrong seqs
+		{chainID, []int64{1}, fee, newTestMsg(addr2), codeUnauth},  // test wrong msg
+		{chainID, []int64{1}, fee2, newTestMsg(addr2), codeUnauth}, // test wrong fee
+		{chainID, []int64{1}, fee3, newTestMsg(addr2), codeUnauth}, // test wrong fee
 	}
 
 	privs, seqs = []crypto.PrivKey{priv1}, []int64{1}
diff --git a/x/auth/baseaccount_test.go b/x/auth/baseaccount_test.go
index 85adc8cdca..b2f5b54ae2 100644
--- a/x/auth/baseaccount_test.go
+++ b/x/auth/baseaccount_test.go
@@ -27,7 +27,7 @@ func TestBaseAccountAddressPubKey(t *testing.T) {
 	assert.EqualValues(t, addr1, acc.GetAddress())
 	assert.EqualValues(t, crypto.PubKey{}, acc.GetPubKey())
 
-	// cant override address
+	// can't override address
 	err := acc.SetAddress(addr2)
 	assert.NotNil(t, err)
 	assert.EqualValues(t, addr1, acc.GetAddress())
@@ -37,7 +37,7 @@ func TestBaseAccountAddressPubKey(t *testing.T) {
 	assert.Nil(t, err)
 	assert.Equal(t, pub1, acc.GetPubKey())
 
-	// cant override pubkey
+	// can't override pubkey
 	err = acc.SetPubKey(pub2)
 	assert.NotNil(t, err)
 	assert.Equal(t, pub1, acc.GetPubKey())
@@ -111,6 +111,7 @@ func TestBaseAccountGetSet(t *testing.T) {
 	_, _, addr := keyPubAddr()
 	acc := NewBaseAccountWithAddress(addr)
 
+	// Get/Set are not yet defined - all values cause a panic.
 	assert.Panics(t, func() { acc.Get("key") })
 	assert.Panics(t, func() { acc.Set("key", "value") })
 }