Add negative tests for MsgTx.

This commit adds tests for the error paths when encoding and decoding
MsgTx.  This commit also achieves 100% test coverage.

msgtx_test.go

@@ -8,6 +8,7 @@ import (
 	"bytes"
 	"github.com/conformal/btcwire"
 	"github.com/davecgh/go-spew/spew"
+	"io"
 	"reflect"
 	"testing"
 )
@@ -301,6 +302,73 @@ func TestTxWire(t *testing.T) {
 	}
 }
 
+// TestTxWireErrors performs negative tests against wire encode and decode
+// of MsgTx to confirm error paths work correctly.
+func TestTxWireErrors(t *testing.T) {
+	// Use protocol version 60002 specifically here instead of the latest
+	// because the test data is using bytes encoded with that protocol
+	// version.
+	pver := uint32(60002)
+
+	tests := []struct {
+		in       *btcwire.MsgTx // Value to encode
+		buf      []byte         // Wire encoding
+		pver     uint32         // Protocol version for wire encoding
+		max      int            // Max size of fixed buffer to induce errors
+		writeErr error          // Expected write error
+		readErr  error          // Expected read error
+	}{
+		// Force error in version.
+		{multiTx, multiTxEncoded, pver, 0, io.ErrShortWrite, io.EOF},
+		// Force error in number of transaction inputs.
+		{multiTx, multiTxEncoded, pver, 4, io.ErrShortWrite, io.EOF},
+		// Force error in transaction input previous block hash.
+		{multiTx, multiTxEncoded, pver, 5, io.ErrShortWrite, io.EOF},
+		// Force error in transaction input previous block hash.
+		{multiTx, multiTxEncoded, pver, 5, io.ErrShortWrite, io.EOF},
+		// Force error in transaction input previous block output index.
+		{multiTx, multiTxEncoded, pver, 37, io.ErrShortWrite, io.EOF},
+		// Force error in transaction input signature script length.
+		{multiTx, multiTxEncoded, pver, 41, io.ErrShortWrite, io.EOF},
+		// Force error in transaction input signature script.
+		{multiTx, multiTxEncoded, pver, 42, io.ErrShortWrite, io.EOF},
+		// Force error in transaction input sequence.
+		{multiTx, multiTxEncoded, pver, 49, io.ErrShortWrite, io.EOF},
+		// Force error in number of transaction outputs.
+		{multiTx, multiTxEncoded, pver, 53, io.ErrShortWrite, io.EOF},
+		// Force error in transaction output value.
+		{multiTx, multiTxEncoded, pver, 54, io.ErrShortWrite, io.EOF},
+		// Force error in transaction output pk script length.
+		{multiTx, multiTxEncoded, pver, 62, io.ErrShortWrite, io.EOF},
+		// Force error in transaction output pk script.
+		{multiTx, multiTxEncoded, pver, 63, io.ErrShortWrite, io.EOF},
+		// Force error in transaction output lock time.
+		{multiTx, multiTxEncoded, pver, 130, io.ErrShortWrite, io.EOF},
+	}
+
+	t.Logf("Running %d tests", len(tests))
+	for i, test := range tests {
+		// Encode to wire format.
+		w := newFixedWriter(test.max)
+		err := test.in.BtcEncode(w, test.pver)
+		if err != test.writeErr {
+			t.Errorf("BtcEncode #%d wrong error got: %v, want: %v",
+				i, err, test.writeErr)
+			continue
+		}
+
+		// Decode from wire format.
+		var msg btcwire.MsgTx
+		r := newFixedReader(test.max, test.buf)
+		err = msg.BtcDecode(r, test.pver)
+		if err != test.readErr {
+			t.Errorf("BtcDecode #%d wrong error got: %v, want: %v",
+				i, err, test.readErr)
+			continue
+		}
+	}
+}
+
 // multiTx is a MsgTx with an input and output and used in various tests.
 var multiTx *btcwire.MsgTx = &btcwire.MsgTx{
 	Version: 1,

test_coverage.txt

@@ -1,81 +1,89 @@
 
 github.com/conformal/btcwire/message.go		 ReadMessage				 100.00% (37/37)
 github.com/conformal/btcwire/message.go		 WriteMessage				 100.00% (27/27)
+github.com/conformal/btcwire/msgtx.go		 MsgTx.BtcDecode			 100.00% (25/25)
 github.com/conformal/btcwire/msgversion.go	 MsgVersion.BtcDecode			 100.00% (25/25)
 github.com/conformal/btcwire/msgtx.go		 MsgTx.Copy				 100.00% (24/24)
 github.com/conformal/btcwire/common.go		 readVarInt				 100.00% (24/24)
+github.com/conformal/btcwire/msgtx.go		 MsgTx.BtcEncode			 100.00% (23/23)
 github.com/conformal/btcwire/msgversion.go	 MsgVersion.BtcEncode			 100.00% (22/22)
 github.com/conformal/btcwire/netaddress.go	 readNetAddress				 100.00% (20/20)
 github.com/conformal/btcwire/message.go		 makeEmptyMessage			 100.00% (20/20)
-github.com/conformal/btcwire/msggetblocks.go	 MsgGetBlocks.BtcDecode			 100.00% (19/19)
 github.com/conformal/btcwire/msggetheaders.go	 MsgGetHeaders.BtcDecode		 100.00% (19/19)
+github.com/conformal/btcwire/msggetblocks.go	 MsgGetBlocks.BtcDecode			 100.00% (19/19)
 github.com/conformal/btcwire/msggetblocks.go	 MsgGetBlocks.BtcEncode			 100.00% (18/18)
 github.com/conformal/btcwire/msggetheaders.go	 MsgGetHeaders.BtcEncode		 100.00% (18/18)
+github.com/conformal/btcwire/msgtx.go		 readTxIn				 100.00% (17/17)
+github.com/conformal/btcwire/msgheaders.go	 MsgHeaders.BtcDecode			 100.00% (16/16)
 github.com/conformal/btcwire/msgblock.go	 MsgBlock.BtcDecodeTxLoc		 100.00% (16/16)
 github.com/conformal/btcwire/common.go		 writeVarInt				 100.00% (16/16)
-github.com/conformal/btcwire/msgheaders.go	 MsgHeaders.BtcDecode			 100.00% (16/16)
-github.com/conformal/btcwire/shahash.go		 NewShaHashFromStr			 100.00% (15/15)
 github.com/conformal/btcwire/msgaddr.go		 MsgAddr.BtcEncode			 100.00% (15/15)
 github.com/conformal/btcwire/msgheaders.go	 MsgHeaders.BtcEncode			 100.00% (15/15)
+github.com/conformal/btcwire/shahash.go		 NewShaHashFromStr			 100.00% (15/15)
+github.com/conformal/btcwire/msgtx.go		 writeTxIn				 100.00% (15/15)
 github.com/conformal/btcwire/netaddress.go	 writeNetAddress			 100.00% (14/14)
-github.com/conformal/btcwire/msggetdata.go	 MsgGetData.BtcDecode			 100.00% (13/13)
 github.com/conformal/btcwire/msginv.go		 MsgInv.BtcDecode			 100.00% (13/13)
+github.com/conformal/btcwire/msggetdata.go	 MsgGetData.BtcDecode			 100.00% (13/13)
 github.com/conformal/btcwire/msgnotfound.go	 MsgNotFound.BtcDecode			 100.00% (13/13)
 github.com/conformal/btcwire/msgaddr.go		 MsgAddr.BtcDecode			 100.00% (13/13)
-github.com/conformal/btcwire/msginv.go		 MsgInv.BtcEncode			 100.00% (12/12)
+github.com/conformal/btcwire/msgnotfound.go	 MsgNotFound.BtcEncode			 100.00% (12/12)
 github.com/conformal/btcwire/msggetdata.go	 MsgGetData.BtcEncode			 100.00% (12/12)
 github.com/conformal/btcwire/protocol.go	 ServiceFlag.String			 100.00% (12/12)
-github.com/conformal/btcwire/msgnotfound.go	 MsgNotFound.BtcEncode			 100.00% (12/12)
+github.com/conformal/btcwire/msginv.go		 MsgInv.BtcEncode			 100.00% (12/12)
+github.com/conformal/btcwire/msgtx.go		 readTxOut				 100.00% (12/12)
+github.com/conformal/btcwire/msgtx.go		 writeTxOut				 100.00% (11/11)
+github.com/conformal/btcwire/blockheader.go	 readBlockHeader			 100.00% (10/10)
 github.com/conformal/btcwire/message.go		 discardInput				 100.00% (10/10)
 github.com/conformal/btcwire/msgblock.go	 MsgBlock.BtcDecode			 100.00% (10/10)
-github.com/conformal/btcwire/blockheader.go	 readBlockHeader			 100.00% (10/10)
 github.com/conformal/btcwire/msgblock.go	 MsgBlock.BtcEncode			 100.00% (9/9)
-github.com/conformal/btcwire/msgalert.go	 MsgAlert.BtcDecode			 100.00% (8/8)
 github.com/conformal/btcwire/common.go		 readVarString				 100.00% (8/8)
-github.com/conformal/btcwire/msgalert.go	 MsgAlert.BtcEncode			 100.00% (8/8)
 github.com/conformal/btcwire/blockheader.go	 writeBlockHeader			 100.00% (8/8)
-github.com/conformal/btcwire/common.go		 writeVarString				 100.00% (7/7)
+github.com/conformal/btcwire/msgalert.go	 MsgAlert.BtcDecode			 100.00% (8/8)
+github.com/conformal/btcwire/msgalert.go	 MsgAlert.BtcEncode			 100.00% (8/8)
+github.com/conformal/btcwire/msgpong.go		 MsgPong.BtcEncode			 100.00% (7/7)
+github.com/conformal/btcwire/msgpong.go		 MsgPong.BtcDecode			 100.00% (7/7)
+github.com/conformal/btcwire/msgversion.go	 NewMsgVersionFromConn			 100.00% (7/7)
 github.com/conformal/btcwire/message.go		 readMessageHeader			 100.00% (7/7)
 github.com/conformal/btcwire/common.go		 DoubleSha256				 100.00% (7/7)
+github.com/conformal/btcwire/common.go		 writeVarString				 100.00% (7/7)
 github.com/conformal/btcwire/common.go		 randomUint64				 100.00% (7/7)
-github.com/conformal/btcwire/msgpong.go		 MsgPong.BtcEncode			 100.00% (7/7)
-github.com/conformal/btcwire/msgversion.go	 NewMsgVersionFromConn			 100.00% (7/7)
-github.com/conformal/btcwire/msgpong.go		 MsgPong.BtcDecode			 100.00% (7/7)
-github.com/conformal/btcwire/blockheader.go	 BlockHeader.BlockSha			 100.00% (5/5)
-github.com/conformal/btcwire/msginv.go		 MsgInv.AddInvVect			 100.00% (5/5)
-github.com/conformal/btcwire/msgnotfound.go	 MsgNotFound.AddInvVect			 100.00% (5/5)
 github.com/conformal/btcwire/msgping.go		 MsgPing.BtcDecode			 100.00% (5/5)
+github.com/conformal/btcwire/msgnotfound.go	 MsgNotFound.AddInvVect			 100.00% (5/5)
 github.com/conformal/btcwire/msgping.go		 MsgPing.BtcEncode			 100.00% (5/5)
 github.com/conformal/btcwire/msgblock.go	 MsgBlock.TxShas			 100.00% (5/5)
 github.com/conformal/btcwire/common.go		 readElements				 100.00% (5/5)
 github.com/conformal/btcwire/msgtx.go		 MsgTx.TxSha				 100.00% (5/5)
-github.com/conformal/btcwire/shahash.go		 NewShaHash				 100.00% (5/5)
+github.com/conformal/btcwire/blockheader.go	 BlockHeader.BlockSha			 100.00% (5/5)
-github.com/conformal/btcwire/shahash.go		 ShaHash.SetBytes			 100.00% (5/5)
-github.com/conformal/btcwire/netaddress.go	 NewNetAddress				 100.00% (5/5)
 github.com/conformal/btcwire/msggetblocks.go	 MsgGetBlocks.AddBlockLocatorHash	 100.00% (5/5)
 github.com/conformal/btcwire/msggetdata.go	 MsgGetData.AddInvVect			 100.00% (5/5)
+github.com/conformal/btcwire/netaddress.go	 NewNetAddress				 100.00% (5/5)
+github.com/conformal/btcwire/shahash.go		 ShaHash.SetBytes			 100.00% (5/5)
+github.com/conformal/btcwire/shahash.go		 NewShaHash				 100.00% (5/5)
 github.com/conformal/btcwire/msgaddr.go		 MsgAddr.AddAddress			 100.00% (5/5)
 github.com/conformal/btcwire/msggetheaders.go	 MsgGetHeaders.AddBlockLocatorHash	 100.00% (5/5)
 github.com/conformal/btcwire/msgaddr.go		 MsgAddr.AddAddresses			 100.00% (5/5)
 github.com/conformal/btcwire/msgheaders.go	 MsgHeaders.AddBlockHeader		 100.00% (5/5)
 github.com/conformal/btcwire/common.go		 writeElements				 100.00% (5/5)
-github.com/conformal/btcwire/netaddress.go	 maxNetAddressPayload			 100.00% (4/4)
+github.com/conformal/btcwire/msginv.go		 MsgInv.AddInvVect			 100.00% (5/5)
-github.com/conformal/btcwire/invvect.go		 readInvVect				 100.00% (4/4)
-github.com/conformal/btcwire/msgmempool.go	 MsgMemPool.BtcEncode			 100.00% (4/4)
 github.com/conformal/btcwire/msgpong.go		 MsgPong.MaxPayloadLength		 100.00% (4/4)
-github.com/conformal/btcwire/msgping.go		 MsgPing.MaxPayloadLength		 100.00% (4/4)
+github.com/conformal/btcwire/netaddress.go	 maxNetAddressPayload			 100.00% (4/4)
-github.com/conformal/btcwire/msgmempool.go	 MsgMemPool.BtcDecode			 100.00% (4/4)
 github.com/conformal/btcwire/invvect.go		 writeInvVect				 100.00% (4/4)
+github.com/conformal/btcwire/msgtx.go		 writeOutPoint				 100.00% (4/4)
+github.com/conformal/btcwire/invvect.go		 readInvVect				 100.00% (4/4)
+github.com/conformal/btcwire/msgping.go		 MsgPing.MaxPayloadLength		 100.00% (4/4)
+github.com/conformal/btcwire/msgmempool.go	 MsgMemPool.BtcEncode			 100.00% (4/4)
 github.com/conformal/btcwire/shahash.go		 ShaHash.String				 100.00% (4/4)
-github.com/conformal/btcwire/msgblock.go	 MsgBlock.AddTransaction		 100.00% (3/3)
+github.com/conformal/btcwire/msgtx.go		 readOutPoint				 100.00% (4/4)
+github.com/conformal/btcwire/msgmempool.go	 MsgMemPool.BtcDecode			 100.00% (4/4)
 github.com/conformal/btcwire/netaddress.go	 NetAddress.HasService			 100.00% (3/3)
 github.com/conformal/btcwire/msgversion.go	 MsgVersion.HasService			 100.00% (3/3)
-github.com/conformal/btcwire/shahash.go		 ShaHash.Bytes				 100.00% (3/3)
-github.com/conformal/btcwire/invvect.go		 InvType.String				 100.00% (3/3)
-github.com/conformal/btcwire/error.go		 MessageError.Error			 100.00% (3/3)
 github.com/conformal/btcwire/msgaddr.go		 MsgAddr.MaxPayloadLength		 100.00% (3/3)
-github.com/conformal/btcwire/msgblock.go	 MsgBlock.ClearTransactions		 100.00% (2/2)
+github.com/conformal/btcwire/invvect.go		 InvType.String				 100.00% (3/3)
+github.com/conformal/btcwire/msgblock.go	 MsgBlock.AddTransaction		 100.00% (3/3)
+github.com/conformal/btcwire/error.go		 MessageError.Error			 100.00% (3/3)
+github.com/conformal/btcwire/shahash.go		 ShaHash.Bytes				 100.00% (3/3)
 github.com/conformal/btcwire/netaddress.go	 NetAddress.SetAddress			 100.00% (2/2)
+github.com/conformal/btcwire/msgblock.go	 MsgBlock.ClearTransactions		 100.00% (2/2)
 github.com/conformal/btcwire/msgheaders.go	 MsgHeaders.Command			 100.00% (1/1)
 github.com/conformal/btcwire/blockheader.go	 NewBlockHeader				 100.00% (1/1)
 github.com/conformal/btcwire/common.go		 readElement				 100.00% (1/1)
@@ -141,13 +149,5 @@ github.com/conformal/btcwire/msgversion.go	 NewMsgVersion				 100.00% (1/1)
 github.com/conformal/btcwire/netaddress.go	 NetAddress.AddService			 100.00% (1/1)
 github.com/conformal/btcwire/shahash.go		 ShaHash.IsEqual			 100.00% (1/1)
 github.com/conformal/btcwire/invvect.go		 NewInvVect				 100.00% (1/1)
-github.com/conformal/btcwire/msgtx.go		 MsgTx.BtcDecode			 80.00% (20/25)
+github.com/conformal/btcwire			 ---------------------------------	 100.00% (923/923)
-github.com/conformal/btcwire/msgtx.go		 MsgTx.BtcEncode			 78.26% (18/23)
-github.com/conformal/btcwire/msgtx.go		 readTxIn				 76.47% (13/17)
-github.com/conformal/btcwire/msgtx.go		 readTxOut				 75.00% (9/12)
-github.com/conformal/btcwire/msgtx.go		 readOutPoint				 75.00% (3/4)
-github.com/conformal/btcwire/msgtx.go		 writeOutPoint				 75.00% (3/4)
-github.com/conformal/btcwire/msgtx.go		 writeTxIn				 73.33% (11/15)
-github.com/conformal/btcwire/msgtx.go		 writeTxOut				 72.73% (8/11)
-github.com/conformal/btcwire			 ---------------------------------	 97.18% (897/923)