Add check that vpubs are not both nonzero and test it.

src/Makefile.gtest.include

@@ -3,11 +3,18 @@ bin_PROGRAMS += zcash-gtest
 # tool for generating our public parameters
 zcash_gtest_SOURCES = \
 	gtest/main.cpp \
-	gtest/test_tautology.cpp
+	gtest/test_tautology.cpp \
+	gtest/test_checktransaction.cpp
 
-zcash_gtest_LDADD = \
-  -lgtest \
-  $(LIBBITCOIN_UTIL)
+zcash_gtest_LDADD = -lgtest $(LIBBITCOIN_SERVER) $(LIBBITCOIN_CLI) $(LIBBITCOIN_COMMON) $(LIBBITCOIN_UTIL) $(LIBBITCOIN_CRYPTO) $(LIBBITCOIN_UNIVALUE) $(LIBLEVELDB) $(LIBMEMENV) \
+  $(BOOST_LIBS) $(BOOST_UNIT_TEST_FRAMEWORK_LIB) $(LIBSECP256K1)
+if ENABLE_WALLET
+zcash_gtest_LDADD += $(LIBBITCOIN_WALLET)
+endif
+
+zcash_gtest_LDADD += $(LIBBITCOIN_CONSENSUS) $(BDB_LIBS) $(SSL_LIBS) $(CRYPTO_LIBS) $(MINIUPNPC_LIBS) $(LIBZEROCASH) $(LIBZEROCASH_LIBS)
+
+zcash_gtest_LDFLAGS = $(RELDFLAGS) $(AM_LDFLAGS) $(LIBTOOL_APP_LDFLAGS) -static
 
 zcash-gtest_check: zcash-gtest FORCE
 	./zcash-gtest

src/gtest/test_checktransaction.cpp

@@ -0,0 +1,26 @@
+#include <gtest/gtest.h>
+
+#include "main.h"
+#include "primitives/transaction.h"
+#include "consensus/validation.h"
+
+TEST(checktransaction_tests, check_vpub_not_both_nonzero) {
+    CMutableTransaction tx;
+    tx.nVersion = 2;
+
+    {
+        // Ensure that values within the pour are well-formed.
+        CMutableTransaction newTx(tx);
+        CValidationState state;
+        state.SetPerformPourVerification(false); // don't verify the snark
+
+        newTx.vpour.push_back(CPourTx());
+
+        CPourTx *pourtx = &newTx.vpour[0];
+        pourtx->vpub_old = 1;
+        pourtx->vpub_new = 1;
+
+        EXPECT_FALSE(CheckTransaction(newTx, state));
+        EXPECT_EQ(state.GetRejectReason(), "bad-txns-vpubs-both-nonzero");
+    }
+}

src/main.cpp

@@ -881,26 +881,36 @@ bool CheckTransaction(const CTransaction& tx, CValidationState &state)
     // Ensure that pour values are well-formed
     BOOST_FOREACH(const CPourTx& pour, tx.vpour)
     {
-        if (pour.vpub_old < 0)
+        if (pour.vpub_old < 0) {
             return state.DoS(100, error("CheckTransaction(): pour.vpub_old negative"),
                              REJECT_INVALID, "bad-txns-vpub_old-negative");
+        }
 
-        if (pour.vpub_new < 0)
+        if (pour.vpub_new < 0) {
             return state.DoS(100, error("CheckTransaction(): pour.vpub_new negative"),
                              REJECT_INVALID, "bad-txns-vpub_new-negative");
+        }
 
-        if (pour.vpub_old > MAX_MONEY)
+        if (pour.vpub_old > MAX_MONEY) {
             return state.DoS(100, error("CheckTransaction(): pour.vpub_old too high"),
                              REJECT_INVALID, "bad-txns-vpub_old-toolarge");
+        }
 
-        if (pour.vpub_new > MAX_MONEY)
+        if (pour.vpub_new > MAX_MONEY) {
             return state.DoS(100, error("CheckTransaction(): pour.vpub_new too high"),
                              REJECT_INVALID, "bad-txns-vpub_new-toolarge");
+        }
+
+        if (pour.vpub_new != 0 && pour.vpub_old != 0) {
+            return state.DoS(100, error("CheckTransaction(): pour.vpub_new and pour.vpub_old both nonzero"),
+                             REJECT_INVALID, "bad-txns-vpubs-both-nonzero");
+        }
 
         nValueOut += pour.vpub_new;
-        if (!MoneyRange(nValueOut))
+        if (!MoneyRange(nValueOut)) {
             return state.DoS(100, error("CheckTransaction(): txout total out of range"),
                              REJECT_INVALID, "bad-txns-txouttotal-toolarge");
+        }
     }