Refactor test code to better test JSDescription::Randomized()

src/Makefile.gtest.include

@@ -4,6 +4,7 @@ bin_PROGRAMS += zcash-gtest
 # tool for generating our public parameters
 zcash_gtest_SOURCES = \
 	gtest/main.cpp \
+	gtest/utils.cpp \
 	gtest/test_checktransaction.cpp \
 	gtest/json_test_vectors.cpp \
         gtest/json_test_vectors.h \
@@ -19,6 +20,7 @@ zcash_gtest_SOURCES = \
 	gtest/test_pow.cpp \
 	gtest/test_random.cpp \
 	gtest/test_rpc.cpp \
+	gtest/test_transaction.cpp \
 	gtest/test_circuit.cpp \
 	gtest/test_txid.cpp \
 	gtest/test_libzcash_utils.cpp \

src/gtest/test_random.cpp

@@ -2,15 +2,8 @@
 
 #include "random.h"
 
-int GenZero(int n)
-{
-    return 0;
-}
-
-int GenMax(int n)
-{
-    return n-1;
-}
+extern int GenZero(int n);
+extern int GenMax(int n);
 
 TEST(Random, MappedShuffle) {
     std::vector<int> a {8, 4, 6, 3, 5};

src/gtest/test_transaction.cpp

@@ -0,0 +1,85 @@
+#include <gtest/gtest.h>
+
+#include "primitives/transaction.h"
+#include "zcash/Note.hpp"
+#include "zcash/Address.hpp"
+
+extern ZCJoinSplit* params;
+extern int GenZero(int n);
+extern int GenMax(int n);
+
+TEST(Transaction, JSDescriptionRandomized) {
+    // construct a merkle tree
+    ZCIncrementalMerkleTree merkleTree;
+
+    libzcash::SpendingKey k = libzcash::SpendingKey::random();
+    libzcash::PaymentAddress addr = k.address();
+
+    libzcash::Note note(addr.a_pk, 100, uint256(), uint256());
+
+    // commitment from coin
+    uint256 commitment = note.cm();
+
+    // insert commitment into the merkle tree
+    merkleTree.append(commitment);
+
+    // compute the merkle root we will be working with
+    uint256 rt = merkleTree.root();
+
+    auto witness = merkleTree.witness();
+
+    // create JSDescription
+    uint256 pubKeyHash;
+    boost::array<libzcash::JSInput, ZC_NUM_JS_INPUTS> inputs = {
+        libzcash::JSInput(witness, note, k),
+        libzcash::JSInput() // dummy input of zero value
+    };
+    boost::array<libzcash::JSOutput, ZC_NUM_JS_OUTPUTS> outputs = {
+        libzcash::JSOutput(addr, 50),
+        libzcash::JSOutput(addr, 50)
+    };
+    boost::array<size_t, ZC_NUM_JS_INPUTS> inputMap;
+    boost::array<size_t, ZC_NUM_JS_OUTPUTS> outputMap;
+
+    {
+        auto jsdesc = JSDescription::Randomized(
+            *params, pubKeyHash, rt,
+            inputs, outputs,
+            inputMap, outputMap,
+            0, 0, false);
+
+        std::set<size_t> inputSet(inputMap.begin(), inputMap.end());
+        std::set<size_t> expectedInputSet {0, 1};
+        EXPECT_EQ(expectedInputSet, inputSet);
+
+        std::set<size_t> outputSet(outputMap.begin(), outputMap.end());
+        std::set<size_t> expectedOutputSet {0, 1};
+        EXPECT_EQ(expectedOutputSet, outputSet);
+    }
+
+    {
+        auto jsdesc = JSDescription::Randomized(
+            *params, pubKeyHash, rt,
+            inputs, outputs,
+            inputMap, outputMap,
+            0, 0, false, GenZero);
+
+        boost::array<size_t, ZC_NUM_JS_INPUTS> expectedInputMap {1, 0};
+        boost::array<size_t, ZC_NUM_JS_OUTPUTS> expectedOutputMap {1, 0};
+        EXPECT_EQ(expectedInputMap, inputMap);
+        EXPECT_EQ(expectedOutputMap, outputMap);
+    }
+
+    {
+        auto jsdesc = JSDescription::Randomized(
+            *params, pubKeyHash, rt,
+            inputs, outputs,
+            inputMap, outputMap,
+            0, 0, false, GenMax);
+
+        boost::array<size_t, ZC_NUM_JS_INPUTS> expectedInputMap {0, 1};
+        boost::array<size_t, ZC_NUM_JS_OUTPUTS> expectedOutputMap {0, 1};
+        EXPECT_EQ(expectedInputMap, inputMap);
+        EXPECT_EQ(expectedOutputMap, outputMap);
+    }
+}

src/gtest/utils.cpp

@@ -0,0 +1,13 @@
+#include "zcash/JoinSplit.hpp"
+
+ZCJoinSplit* params = ZCJoinSplit::Unopened();
+
+int GenZero(int n)
+{
+    return 0;
+}
+
+int GenMax(int n)
+{
+    return n-1;
+}

src/primitives/transaction.cpp

@@ -6,7 +6,6 @@
 #include "primitives/transaction.h"
 
 #include "hash.h"
-#include "random.h"
 #include "tinyformat.h"
 #include "utilstrencodings.h"
 
@@ -52,13 +51,14 @@ JSDescription JSDescription::Randomized(
             boost::array<size_t, ZC_NUM_JS_OUTPUTS>& outputMap,
             CAmount vpub_old,
             CAmount vpub_new,
-            bool computeProof)
+            bool computeProof,
+            std::function<int(int)> gen)
 {
     // Randomize the order of the inputs and outputs
     inputMap = {0, 1};
     outputMap = {0, 1};
-    MappedShuffle(inputs.begin(), inputMap.begin(), ZC_NUM_JS_INPUTS, GetRandInt);
-    MappedShuffle(outputs.begin(), outputMap.begin(), ZC_NUM_JS_OUTPUTS, GetRandInt);
+    MappedShuffle(inputs.begin(), inputMap.begin(), ZC_NUM_JS_INPUTS, gen);
+    MappedShuffle(outputs.begin(), outputMap.begin(), ZC_NUM_JS_OUTPUTS, gen);
 
     return JSDescription(
         params, pubKeyHash, anchor, inputs, outputs,

src/primitives/transaction.h

@@ -7,6 +7,7 @@
 #define BITCOIN_PRIMITIVES_TRANSACTION_H
 
 #include "amount.h"
+#include "random.h"
 #include "script/script.h"
 #include "serialize.h"
 #include "uint256.h"
@@ -88,7 +89,8 @@ public:
             boost::array<size_t, ZC_NUM_JS_OUTPUTS>& outputMap,
             CAmount vpub_old,
             CAmount vpub_new,
-            bool computeProof = true // Set to false in some tests
+            bool computeProof = true, // Set to false in some tests
+            std::function<int(int)> gen = GetRandInt
     );
 
     // Verifies that the JoinSplit proof is correct.

src/test/transaction_tests.cpp

@@ -367,34 +367,6 @@ BOOST_AUTO_TEST_CASE(test_basic_joinsplit_verification)
         test.anchor = GetRandHash();
         BOOST_CHECK(!test.Verify(*p, pubKeyHash));
     }
-
-    {
-        boost::array<size_t, ZC_NUM_JS_INPUTS> inputMap;
-        boost::array<size_t, ZC_NUM_JS_OUTPUTS> outputMap;
-        auto jsdesc = JSDescription::Randomized(
-            *p, pubKeyHash, rt,
-            inputs, outputs,
-            inputMap, outputMap,
-            0, 0);
-        BOOST_CHECK(jsdesc.Verify(*p, pubKeyHash));
-
-        std::set<size_t> inputSet;
-        for (size_t i = 0; i < ZC_NUM_JS_INPUTS; i++) {
-            inputSet.insert(inputMap[i]);
-        }
-        std::set<size_t> expectedInputSet {0, 1};
-        BOOST_CHECK(expectedInputSet == inputSet);
-
-        std::set<size_t> outputSet;
-        for (size_t i = 0; i < ZC_NUM_JS_OUTPUTS; i++) {
-            outputSet.insert(outputMap[i]);
-        }
-        std::set<size_t> expectedOutputSet {0, 1};
-        BOOST_CHECK(expectedOutputSet == outputSet);
-    }
-
-
-    delete p;
 }
 
 BOOST_AUTO_TEST_CASE(test_simple_joinsplit_invalidity)

src/wallet/gtest/test_wallet.cpp

@@ -13,7 +13,7 @@
 
 using ::testing::Return;
 
-ZCJoinSplit* params = ZCJoinSplit::Unopened();
+extern ZCJoinSplit* params;
 
 ACTION(ThrowLogicError) {
     throw std::logic_error("Boom");