Add negative tests for MsgAlert.

This commit adds tests for the error paths when encoding and decoding
MsgAlert.

msgalert_test.go

@@ -8,6 +8,7 @@ import (
 	"bytes"
 	"github.com/conformal/btcwire"
 	"github.com/davecgh/go-spew/spew"
+	"io"
 	"reflect"
 	"testing"
 )
@@ -137,3 +138,78 @@ func TestAlertWire(t *testing.T) {
 		}
 	}
 }
+
+// TestAlertWireErrors performs negative tests against wire encode and decode
+// of MsgAlert to confirm error paths work correctly.
+func TestAlertWireErrors(t *testing.T) {
+	pver := btcwire.ProtocolVersion
+
+	baseAlert := btcwire.NewMsgAlert("some payload", "somesig")
+	baseAlertEncoded := []byte{
+		0x0c, // Varint for payload length
+		0x73, 0x6f, 0x6d, 0x65, 0x20, 0x70, 0x61, 0x79,
+		0x6c, 0x6f, 0x61, 0x64, // "some payload"
+		0x07,                                     // Varint for signature length
+		0x73, 0x6f, 0x6d, 0x65, 0x73, 0x69, 0x67, // "somesig"
+	}
+
+	tests := []struct {
+		in       *btcwire.MsgAlert // 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 payload length.
+		{baseAlert, baseAlertEncoded, pver, 0, io.ErrShortWrite, io.EOF},
+		// Force error in payload.
+		{baseAlert, baseAlertEncoded, pver, 1, io.ErrShortWrite, io.EOF},
+		// Force error in signature length.
+		{baseAlert, baseAlertEncoded, pver, 13, io.ErrShortWrite, io.EOF},
+		// Force error in signature.
+		{baseAlert, baseAlertEncoded, pver, 14, 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 reflect.TypeOf(err) != reflect.TypeOf(test.writeErr) {
+			t.Errorf("BtcEncode #%d wrong error got: %v, want: %v",
+				i, err, test.writeErr)
+			continue
+		}
+
+		// For errors which are not of type btcwire.MessageError, check
+		// them for equality.
+		if _, ok := err.(*btcwire.MessageError); !ok {
+			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.MsgAlert
+		r := newFixedReader(test.max, test.buf)
+		err = msg.BtcDecode(r, test.pver)
+		if reflect.TypeOf(err) != reflect.TypeOf(test.readErr) {
+			t.Errorf("BtcDecode #%d wrong error got: %v, want: %v",
+				i, err, test.readErr)
+			continue
+		}
+
+		// For errors which are not of type btcwire.MessageError, check
+		// them for equality.
+		if _, ok := err.(*btcwire.MessageError); !ok {
+			if err != test.readErr {
+				t.Errorf("BtcDecode #%d wrong error got: %v, "+
+					"want: %v", i, err, test.readErr)
+				continue
+			}
+		}
+	}
+}

test_coverage.txt

@@ -4,8 +4,8 @@ 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/message.go		 makeEmptyMessage			 100.00% (20/20)
 github.com/conformal/btcwire/netaddress.go	 readNetAddress				 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/msgheaders.go	 MsgHeaders.BtcDecode			 100.00% (16/16)
@@ -14,59 +14,61 @@ 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/netaddress.go	 writeNetAddress			 100.00% (14/14)
-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/msggetdata.go	 MsgGetData.BtcDecode			 100.00% (13/13)
 github.com/conformal/btcwire/msginv.go		 MsgInv.BtcDecode			 100.00% (13/13)
-github.com/conformal/btcwire/msginv.go		 MsgInv.BtcEncode			 100.00% (12/12)
+github.com/conformal/btcwire/msgnotfound.go	 MsgNotFound.BtcDecode			 100.00% (13/13)
+github.com/conformal/btcwire/msggetdata.go	 MsgGetData.BtcDecode			 100.00% (13/13)
+github.com/conformal/btcwire/msgaddr.go		 MsgAddr.BtcDecode			 100.00% (13/13)
+github.com/conformal/btcwire/msgnotfound.go	 MsgNotFound.BtcEncode			 100.00% (12/12)
 github.com/conformal/btcwire/protocol.go	 ServiceFlag.String			 100.00% (12/12)
 github.com/conformal/btcwire/msggetdata.go	 MsgGetData.BtcEncode			 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/msgblock.go	 MsgBlock.BtcDecode			 100.00% (10/10)
 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/msgblock.go	 MsgBlock.BtcEncode			 100.00% (9/9)
+github.com/conformal/btcwire/msgalert.go	 MsgAlert.BtcEncode			 100.00% (8/8)
 github.com/conformal/btcwire/common.go		 readVarString				 100.00% (8/8)
+github.com/conformal/btcwire/msgalert.go	 MsgAlert.BtcDecode			 100.00% (8/8)
 github.com/conformal/btcwire/blockheader.go	 writeBlockHeader			 100.00% (8/8)
-github.com/conformal/btcwire/message.go		 readMessageHeader			 100.00% (7/7)
+github.com/conformal/btcwire/msgversion.go	 NewMsgVersionFromConn			 100.00% (7/7)
+github.com/conformal/btcwire/common.go		 DoubleSha256				 100.00% (7/7)
 github.com/conformal/btcwire/msgpong.go		 MsgPong.BtcDecode			 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/common.go		 writeVarString				 100.00% (7/7)
-github.com/conformal/btcwire/common.go		 DoubleSha256				 100.00% (7/7)
 github.com/conformal/btcwire/common.go		 randomUint64				 100.00% (7/7)
+github.com/conformal/btcwire/message.go		 readMessageHeader			 100.00% (7/7)
+github.com/conformal/btcwire/common.go		 writeVarString				 100.00% (7/7)
+github.com/conformal/btcwire/common.go		 writeElements				 100.00% (5/5)
+github.com/conformal/btcwire/msgheaders.go	 MsgHeaders.AddBlockHeader		 100.00% (5/5)
 github.com/conformal/btcwire/msginv.go		 MsgInv.AddInvVect			 100.00% (5/5)
+github.com/conformal/btcwire/shahash.go		 ShaHash.SetBytes			 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/msgping.go		 MsgPing.BtcEncode			 100.00% (5/5)
-github.com/conformal/btcwire/msggetheaders.go	 MsgGetHeaders.AddBlockLocatorHash	 100.00% (5/5)
 github.com/conformal/btcwire/common.go		 readElements				 100.00% (5/5)
 github.com/conformal/btcwire/netaddress.go	 NewNetAddress				 100.00% (5/5)
-github.com/conformal/btcwire/msgnotfound.go	 MsgNotFound.AddInvVect			 100.00% (5/5)
 github.com/conformal/btcwire/msggetblocks.go	 MsgGetBlocks.AddBlockLocatorHash	 100.00% (5/5)
-github.com/conformal/btcwire/shahash.go		 ShaHash.SetBytes			 100.00% (5/5)
 github.com/conformal/btcwire/msggetdata.go	 MsgGetData.AddInvVect			 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/shahash.go		 NewShaHash				 100.00% (5/5)
-github.com/conformal/btcwire/msgaddr.go		 MsgAddr.AddAddresses			 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/msgmempool.go	 MsgMemPool.BtcEncode			 100.00% (4/4)
+github.com/conformal/btcwire/msgpong.go		 MsgPong.MaxPayloadLength		 100.00% (4/4)
+github.com/conformal/btcwire/invvect.go		 writeInvVect				 100.00% (4/4)
+github.com/conformal/btcwire/shahash.go		 ShaHash.String				 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/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		 readInvVect				 100.00% (4/4)
+github.com/conformal/btcwire/shahash.go		 ShaHash.Bytes				 100.00% (3/3)
-github.com/conformal/btcwire/msgpong.go		 MsgPong.MaxPayloadLength		 100.00% (4/4)
+github.com/conformal/btcwire/invvect.go		 InvType.String				 100.00% (3/3)
-github.com/conformal/btcwire/msgmempool.go	 MsgMemPool.BtcEncode			 100.00% (4/4)
-github.com/conformal/btcwire/msgping.go		 MsgPing.MaxPayloadLength		 100.00% (4/4)
-github.com/conformal/btcwire/shahash.go		 ShaHash.String				 100.00% (4/4)
-github.com/conformal/btcwire/invvect.go		 writeInvVect				 100.00% (4/4)
-github.com/conformal/btcwire/netaddress.go	 NetAddress.HasService			 100.00% (3/3)
-github.com/conformal/btcwire/msgaddr.go		 MsgAddr.MaxPayloadLength		 100.00% (3/3)
 github.com/conformal/btcwire/error.go		 MessageError.Error			 100.00% (3/3)
 github.com/conformal/btcwire/msgversion.go	 MsgVersion.HasService			 100.00% (3/3)
 github.com/conformal/btcwire/msgblock.go	 MsgBlock.AddTransaction		 100.00% (3/3)
-github.com/conformal/btcwire/shahash.go		 ShaHash.Bytes				 100.00% (3/3)
+github.com/conformal/btcwire/msgaddr.go		 MsgAddr.MaxPayloadLength		 100.00% (3/3)
-github.com/conformal/btcwire/invvect.go		 InvType.String				 100.00% (3/3)
+github.com/conformal/btcwire/netaddress.go	 NetAddress.HasService			 100.00% (3/3)
-github.com/conformal/btcwire/msgblock.go	 MsgBlock.ClearTransactions		 100.00% (2/2)
 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/msgalert.go	 MsgAlert.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)
@@ -138,9 +140,7 @@ github.com/conformal/btcwire/msgtx.go		 MsgTx.BtcDecode			 80.00% (20/25)
 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/msgalert.go	 MsgAlert.BtcDecode			 75.00% (6/8)
 github.com/conformal/btcwire/blockheader.go	 BlockHeader.BlockSha			 75.00% (6/8)
-github.com/conformal/btcwire/msgalert.go	 MsgAlert.BtcEncode			 75.00% (6/8)
 github.com/conformal/btcwire/msgtx.go		 writeOutPoint				 75.00% (3/4)
 github.com/conformal/btcwire/msgtx.go		 readOutPoint				 75.00% (3/4)
 github.com/conformal/btcwire/msgtx.go		 writeTxIn				 73.33% (11/15)
@@ -149,5 +149,5 @@ github.com/conformal/btcwire/message.go		 WriteMessage				 70.00% (21/30)
 github.com/conformal/btcwire/msgversion.go	 MsgVersion.BtcDecode			 68.00% (17/25)
 github.com/conformal/btcwire/msgversion.go	 MsgVersion.BtcEncode			 63.64% (14/22)
 github.com/conformal/btcwire/msgblock.go	 MsgBlock.BtcDecodeTxLoc		 0.00% (0/16)
-github.com/conformal/btcwire			 ---------------------------------	 91.96% (858/933)
+github.com/conformal/btcwire			 ---------------------------------	 92.39% (862/933)