rpcsrv: test calculatenetworkfee with custom Koblitz-based witness

Value calculated by calculatenetworkfee is enough to pass the real
tx verification. However, network fee may be decreased, so calculations
are not quite accurate. Need to investigate, why.

Signed-off-by: Anna Shaleva <shaleva.ann@nspcc.ru>

pkg/core/native/native_test/cryptolib_verification_test.go

@@ -635,7 +635,7 @@ func TestCryptoLib_KoblitzMultisigVerificationScript(t *testing.T) {
 
 		// Add some more network fee to pay for the witness verification. This value may be calculated precisely,
 		// but let's keep some inaccurate value for the test.
-		tx.NetworkFee += 900_0000
+		tx.NetworkFee = 8995470
 
 		// This transaction (along with the network magic) should be signed by the user's Koblitz private key.
 		msg := constructMsg(t, uint32(e.Chain.GetConfig().Magic), tx)

pkg/services/rpcsrv/server_test.go

@@ -3152,10 +3152,13 @@ func testRPCProtocol(t *testing.T, doRPCCall func(string, string, *testing.T) []
 			body := doRPCCall(`{"jsonrpc": "2.0", "id": 1, "method": "calculatenetworkfee", "params": ["bm90IGEgdHJhbnNhY3Rpb24K"]}"`, httpSrv.URL, t)
 			_ = checkErrGetResult(t, body, true, neorpc.InvalidParamsCode, "Invalid params")
 		})
-		calcReq := func(t *testing.T, tx *transaction.Transaction) []byte {
-			rpc := fmt.Sprintf(`{"jsonrpc": "2.0", "id": 1, "method": "calculatenetworkfee", "params": ["%s"]}"`, base64.StdEncoding.EncodeToString(tx.Bytes()))
+		calcReqExactly := func(t *testing.T, tx string) []byte {
+			rpc := fmt.Sprintf(`{"jsonrpc": "2.0", "id": 1, "method": "calculatenetworkfee", "params": ["%s"]}"`, tx)
 			return doRPCCall(rpc, httpSrv.URL, t)
 		}
+		calcReq := func(t *testing.T, tx *transaction.Transaction) []byte {
+			return calcReqExactly(t, base64.StdEncoding.EncodeToString(tx.Bytes()))
+		}
 		t.Run("non-contract with zero verification", func(t *testing.T) {
 			tx := &transaction.Transaction{
 				Script:  []byte{byte(opcode.RET)},
@@ -3235,6 +3238,13 @@ func testRPCProtocol(t *testing.T, doRPCCall func(string, string, *testing.T) []
 			}
 			checkCalc(t, tx, 2315100) // Perfectly matches FeeIsMultiSigContract() C# test.
 		})
+		t.Run("Koblitz custom multisignature witness", func(t *testing.T) {
+			tx := "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"
+			resp := checkErrGetResult(t, calcReqExactly(t, tx), false, 0)
+			res := new(result.NetworkFee)
+			require.NoError(t, json.Unmarshal(resp, res))
+			require.Equal(t, int64(8995470), res.Value)
+		})
 		checkContract := func(t *testing.T, verAcc util.Uint160, invoc []byte, fee int64) {
 			txScript, err := smartcontract.CreateCallWithAssertScript(chain.UtilityTokenHash(), "transfer",
 				verAcc, verAcc, 1, nil)