ringct: allow no outputs, and add tests for this and fees

2 files changed, 75 insertions, 33 deletions

diff --git a/src/ringct/rctSigs.cpp b/src/ringct/rctSigs.cpp
index a07dbaab3..7b83ca0e2 100644
--- a/src/ringct/rctSigs.cpp
+++ b/src/ringct/rctSigs.cpp
@@ -471,7 +471,6 @@ namespace rct {
     //   Note: For txn fees, the last index in the amounts vector should contain that
     //   Thus the amounts vector will be "one" longer than the destinations vectort
     rctSig genRct(const ctkeyV & inSk, const keyV & destinations, const vector<xmr_amount> amounts, const ctkeyM &mixRing, unsigned int index) {
-        CHECK_AND_ASSERT_THROW_MES(amounts.size() > 0, "Amounts must not be empty");
         CHECK_AND_ASSERT_THROW_MES(amounts.size() == destinations.size() || amounts.size() == destinations.size() + 1, "Different number of amounts/destinations");
         CHECK_AND_ASSERT_THROW_MES(index < mixRing.size(), "Bad index into mixRing");
         for (size_t n = 0; n < mixRing.size(); ++n) {
@@ -536,7 +535,6 @@ namespace rct {
     //   uses the attached ecdh info to find the amounts represented by each output commitment 
     //   must know the destination private key to find the correct amount, else will return a random number    
     bool verRct(const rctSig & rv) {
-        CHECK_AND_ASSERT_THROW_MES(rv.rangeSigs.size() > 0, "Empty rv.rangeSigs");
         CHECK_AND_ASSERT_THROW_MES(rv.outPk.size() == rv.rangeSigs.size(), "Mismatched sizes of rv.outPk and rv.rangeSigs");
 
         size_t i = 0;
diff --git a/tests/unit_tests/ringct.cpp b/tests/unit_tests/ringct.cpp
index ba9d3ecc4..c85f7ce48 100644
--- a/tests/unit_tests/ringct.cpp
+++ b/tests/unit_tests/ringct.cpp
@@ -275,7 +275,7 @@ TEST(ringct, range_proofs_with_fee)
 }
 
 static bool range_proof_test(bool expected_valid,
-    int n_inputs, const uint64_t input_amounts[], int n_outputs, const uint64_t output_amounts[])
+    int n_inputs, const uint64_t input_amounts[], int n_outputs, const uint64_t output_amounts[], bool last_is_fee)
 {
     ctkeyV sc, pc;
     ctkey sctmp, pctmp;
@@ -292,7 +292,8 @@ static bool range_proof_test(bool expected_valid,
     for (int n = 0; n < n_outputs; ++n) {
         amounts.push_back(output_amounts[n]);
         skpkGen(Sk, Pk);
-        destinations.push_back(Pk);
+        if (n < n_outputs - 1 || !last_is_fee)
+          destinations.push_back(Pk);
     }
 
     //compute rct data
@@ -319,189 +320,189 @@ TEST(ringct, range_proofs_reject_empty_outs)
 {
   const uint64_t inputs[] = {5000};
   const uint64_t outputs[] = {};
-  EXPECT_TRUE(range_proof_test(false, NELTS(inputs), inputs, NELTS(outputs), outputs));
+  EXPECT_TRUE(range_proof_test(false, NELTS(inputs), inputs, NELTS(outputs), outputs, false));
 }
 
 TEST(ringct, range_proofs_reject_empty_ins)
 {
   const uint64_t inputs[] = {};
   const uint64_t outputs[] = {5000};
-  EXPECT_TRUE(range_proof_test(false, NELTS(inputs), inputs, NELTS(outputs), outputs));
+  EXPECT_TRUE(range_proof_test(false, NELTS(inputs), inputs, NELTS(outputs), outputs, false));
 }
 
 TEST(ringct, range_proofs_reject_all_empty)
 {
   const uint64_t inputs[] = {};
   const uint64_t outputs[] = {};
-  EXPECT_TRUE(range_proof_test(false, NELTS(inputs), inputs, NELTS(outputs), outputs));
+  EXPECT_TRUE(range_proof_test(false, NELTS(inputs), inputs, NELTS(outputs), outputs, false));
 }
 
-TEST(ringct, range_proofs_reject_zero_empty)
+TEST(ringct, range_proofs_accept_zero_empty)
 {
   const uint64_t inputs[] = {0};
   const uint64_t outputs[] = {};
-  EXPECT_TRUE(range_proof_test(false, NELTS(inputs), inputs, NELTS(outputs), outputs));
+  EXPECT_TRUE(range_proof_test(true, NELTS(inputs), inputs, NELTS(outputs), outputs, false));
 }
 
 TEST(ringct, range_proofs_reject_empty_zero)
 {
   const uint64_t inputs[] = {};
   const uint64_t outputs[] = {0};
-  EXPECT_TRUE(range_proof_test(false, NELTS(inputs), inputs, NELTS(outputs), outputs));
+  EXPECT_TRUE(range_proof_test(false, NELTS(inputs), inputs, NELTS(outputs), outputs, false));
 }
 
 TEST(ringct, range_proofs_accept_zero_zero)
 {
   const uint64_t inputs[] = {0};
   const uint64_t outputs[] = {0};
-  EXPECT_TRUE(range_proof_test(true, NELTS(inputs), inputs, NELTS(outputs), outputs));
+  EXPECT_TRUE(range_proof_test(true, NELTS(inputs), inputs, NELTS(outputs), outputs, false));
 }
 
 TEST(ringct, range_proofs_accept_zero_out_first)
 {
   const uint64_t inputs[] = {5000};
   const uint64_t outputs[] = {0, 5000};
-  EXPECT_TRUE(range_proof_test(true, NELTS(inputs), inputs, NELTS(outputs), outputs));
+  EXPECT_TRUE(range_proof_test(true, NELTS(inputs), inputs, NELTS(outputs), outputs, false));
 }
 
 TEST(ringct, range_proofs_accept_zero_out_last)
 {
   const uint64_t inputs[] = {5000};
   const uint64_t outputs[] = {5000, 0};
-  EXPECT_TRUE(range_proof_test(true, NELTS(inputs), inputs, NELTS(outputs), outputs));
+  EXPECT_TRUE(range_proof_test(true, NELTS(inputs), inputs, NELTS(outputs), outputs, false));
 }
 
 TEST(ringct, range_proofs_accept_zero_out_middle)
 {
   const uint64_t inputs[] = {5000};
   const uint64_t outputs[] = {2500, 0, 2500};
-  EXPECT_TRUE(range_proof_test(true, NELTS(inputs), inputs, NELTS(outputs), outputs));
+  EXPECT_TRUE(range_proof_test(true, NELTS(inputs), inputs, NELTS(outputs), outputs, false));
 }
 
 TEST(ringct, range_proofs_accept_zero_in_first)
 {
   const uint64_t inputs[] = {0, 5000};
   const uint64_t outputs[] = {5000};
-  EXPECT_TRUE(range_proof_test(true, NELTS(inputs), inputs, NELTS(outputs), outputs));
+  EXPECT_TRUE(range_proof_test(true, NELTS(inputs), inputs, NELTS(outputs), outputs, false));
 }
 
 TEST(ringct, range_proofs_accept_zero_in_last)
 {
   const uint64_t inputs[] = {5000, 0};
   const uint64_t outputs[] = {5000};
-  EXPECT_TRUE(range_proof_test(true, NELTS(inputs), inputs, NELTS(outputs), outputs));
+  EXPECT_TRUE(range_proof_test(true, NELTS(inputs), inputs, NELTS(outputs), outputs, false));
 }
 
 TEST(ringct, range_proofs_accept_zero_in_middle)
 {
   const uint64_t inputs[] = {2500, 0, 2500};
   const uint64_t outputs[] = {5000};
-  EXPECT_TRUE(range_proof_test(true, NELTS(inputs), inputs, NELTS(outputs), outputs));
+  EXPECT_TRUE(range_proof_test(true, NELTS(inputs), inputs, NELTS(outputs), outputs, false));
 }
 
 TEST(ringct, range_proofs_reject_single_lower)
 {
   const uint64_t inputs[] = {5000};
   const uint64_t outputs[] = {1};
-  EXPECT_TRUE(range_proof_test(false, NELTS(inputs), inputs, NELTS(outputs), outputs));
+  EXPECT_TRUE(range_proof_test(false, NELTS(inputs), inputs, NELTS(outputs), outputs, false));
 }
 
 TEST(ringct, range_proofs_reject_single_higher)
 {
   const uint64_t inputs[] = {5000};
   const uint64_t outputs[] = {5001};
-  EXPECT_TRUE(range_proof_test(false, NELTS(inputs), inputs, NELTS(outputs), outputs));
+  EXPECT_TRUE(range_proof_test(false, NELTS(inputs), inputs, NELTS(outputs), outputs, false));
 }
 
 TEST(ringct, range_proofs_reject_single_out_negative)
 {
   const uint64_t inputs[] = {5000};
   const uint64_t outputs[] = {(uint64_t)-1000ll};
-  EXPECT_TRUE(range_proof_test(false, NELTS(inputs), inputs, NELTS(outputs), outputs));
+  EXPECT_TRUE(range_proof_test(false, NELTS(inputs), inputs, NELTS(outputs), outputs, false));
 }
 
 TEST(ringct, range_proofs_reject_out_negative_first)
 {
   const uint64_t inputs[] = {5000};
   const uint64_t outputs[] = {(uint64_t)-1000ll, 6000};
-  EXPECT_TRUE(range_proof_test(false, NELTS(inputs), inputs, NELTS(outputs), outputs));
+  EXPECT_TRUE(range_proof_test(false, NELTS(inputs), inputs, NELTS(outputs), outputs, false));
 }
 
 TEST(ringct, range_proofs_reject_out_negative_last)
 {
   const uint64_t inputs[] = {5000};
   const uint64_t outputs[] = {6000, (uint64_t)-1000ll};
-  EXPECT_TRUE(range_proof_test(false, NELTS(inputs), inputs, NELTS(outputs), outputs));
+  EXPECT_TRUE(range_proof_test(false, NELTS(inputs), inputs, NELTS(outputs), outputs, false));
 }
 
 TEST(ringct, range_proofs_reject_out_negative_middle)
 {
   const uint64_t inputs[] = {5000};
   const uint64_t outputs[] = {3000, (uint64_t)-1000ll, 3000};
-  EXPECT_TRUE(range_proof_test(false, NELTS(inputs), inputs, NELTS(outputs), outputs));
+  EXPECT_TRUE(range_proof_test(false, NELTS(inputs), inputs, NELTS(outputs), outputs, false));
 }
 
 TEST(ringct, range_proofs_reject_single_in_negative)
 {
   const uint64_t inputs[] = {(uint64_t)-1000ll};
   const uint64_t outputs[] = {5000};
-  EXPECT_TRUE(range_proof_test(false, NELTS(inputs), inputs, NELTS(outputs), outputs));
+  EXPECT_TRUE(range_proof_test(false, NELTS(inputs), inputs, NELTS(outputs), outputs, false));
 }
 
 TEST(ringct, range_proofs_reject_in_negative_first)
 {
   const uint64_t inputs[] = {(uint64_t)-1000ll, 6000};
   const uint64_t outputs[] = {5000};
-  EXPECT_TRUE(range_proof_test(false, NELTS(inputs), inputs, NELTS(outputs), outputs));
+  EXPECT_TRUE(range_proof_test(false, NELTS(inputs), inputs, NELTS(outputs), outputs, false));
 }
 
 TEST(ringct, range_proofs_reject_in_negative_last)
 {
   const uint64_t inputs[] = {6000, (uint64_t)-1000ll};
   const uint64_t outputs[] = {5000};
-  EXPECT_TRUE(range_proof_test(false, NELTS(inputs), inputs, NELTS(outputs), outputs));
+  EXPECT_TRUE(range_proof_test(false, NELTS(inputs), inputs, NELTS(outputs), outputs, false));
 }
 
 TEST(ringct, range_proofs_reject_in_negative_middle)
 {
   const uint64_t inputs[] = {3000, (uint64_t)-1000ll, 3000};
   const uint64_t outputs[] = {5000};
-  EXPECT_TRUE(range_proof_test(false, NELTS(inputs), inputs, NELTS(outputs), outputs));
+  EXPECT_TRUE(range_proof_test(false, NELTS(inputs), inputs, NELTS(outputs), outputs, false));
 }
 
 TEST(ringct, range_proofs_reject_higher_list)
 {
   const uint64_t inputs[] = {5000};
   const uint64_t outputs[] = {1000, 1000, 1000, 1000, 1000, 1000};
-  EXPECT_TRUE(range_proof_test(false, NELTS(inputs), inputs, NELTS(outputs), outputs));
+  EXPECT_TRUE(range_proof_test(false, NELTS(inputs), inputs, NELTS(outputs), outputs, false));
 }
 
 TEST(ringct, range_proofs_accept_1_to_1)
 {
   const uint64_t inputs[] = {5000};
   const uint64_t outputs[] = {5000};
-  EXPECT_TRUE(range_proof_test(true, NELTS(inputs), inputs, NELTS(outputs), outputs));
+  EXPECT_TRUE(range_proof_test(true, NELTS(inputs), inputs, NELTS(outputs), outputs, false));
 }
 
 TEST(ringct, range_proofs_accept_1_to_N)
 {
   const uint64_t inputs[] = {5000};
   const uint64_t outputs[] = {1000, 1000, 1000, 1000, 1000};
-  EXPECT_TRUE(range_proof_test(true, NELTS(inputs), inputs, NELTS(outputs), outputs));
+  EXPECT_TRUE(range_proof_test(true, NELTS(inputs), inputs, NELTS(outputs), outputs, false));
 }
 
 TEST(ringct, range_proofs_accept_N_to_1)
 {
   const uint64_t inputs[] = {1000, 1000, 1000, 1000, 1000};
   const uint64_t outputs[] = {5000};
-  EXPECT_TRUE(range_proof_test(true, NELTS(inputs), inputs, NELTS(outputs), outputs));
+  EXPECT_TRUE(range_proof_test(true, NELTS(inputs), inputs, NELTS(outputs), outputs, false));
 }
 
 TEST(ringct, range_proofs_accept_N_to_N)
 {
   const uint64_t inputs[] = {1000, 1000, 1000, 1000, 1000};
   const uint64_t outputs[] = {1000, 1000, 1000, 1000, 1000};
-  EXPECT_TRUE(range_proof_test(true, NELTS(inputs), inputs, NELTS(outputs), outputs));
+  EXPECT_TRUE(range_proof_test(true, NELTS(inputs), inputs, NELTS(outputs), outputs, false));
 }
 
 TEST(ringct, range_proofs_accept_very_long)
@@ -515,7 +516,7 @@ TEST(ringct, range_proofs_accept_very_long)
   }
   std::random_shuffle(inputs, inputs + N);
   std::random_shuffle(outputs, outputs + N);
-  EXPECT_TRUE(range_proof_test(true, NELTS(inputs), inputs, NELTS(outputs), outputs));
+  EXPECT_TRUE(range_proof_test(true, NELTS(inputs), inputs, NELTS(outputs), outputs, false));
 }
 
 TEST(ringct, HPow2)
@@ -579,3 +580,46 @@ TEST(ringct, prooveRange_is_non_deterministic)
   ASSERT_TRUE(memcmp(C[0].bytes, C[1].bytes, sizeof(C[0].bytes)));
   ASSERT_TRUE(memcmp(mask[0].bytes, mask[1].bytes, sizeof(mask[0].bytes)));
 }
+
+TEST(ringct, fee_0_valid)
+{
+  const uint64_t inputs[] = {1000, 1000};
+  const uint64_t outputs[] = {2000, 0};
+  EXPECT_TRUE(range_proof_test(true, NELTS(inputs), inputs, NELTS(outputs), outputs, true));
+}
+
+TEST(ringct, fee_non_0_valid)
+{
+  const uint64_t inputs[] = {1000, 1000};
+  const uint64_t outputs[] = {1900, 100};
+  EXPECT_TRUE(range_proof_test(true, NELTS(inputs), inputs, NELTS(outputs), outputs, true));
+}
+
+TEST(ringct, fee_non_0_invalid_higher)
+{
+  const uint64_t inputs[] = {1000, 1000};
+  const uint64_t outputs[] = {1990, 100};
+  EXPECT_TRUE(range_proof_test(false, NELTS(inputs), inputs, NELTS(outputs), outputs, true));
+}
+
+TEST(ringct, fee_non_0_invalid_lower)
+{
+  const uint64_t inputs[] = {1000, 1000};
+  const uint64_t outputs[] = {1000, 100};
+  EXPECT_TRUE(range_proof_test(false, NELTS(inputs), inputs, NELTS(outputs), outputs, true));
+}
+
+TEST(ringct, fee_burn_valid_one_out)
+{
+  const uint64_t inputs[] = {1000, 1000};
+  const uint64_t outputs[] = {0, 2000};
+  EXPECT_TRUE(range_proof_test(true, NELTS(inputs), inputs, NELTS(outputs), outputs, true));
+}
+
+TEST(ringct, fee_burn_valid_zero_out)
+{
+  const uint64_t inputs[] = {1000, 1000};
+  const uint64_t outputs[] = {2000};
+  EXPECT_TRUE(range_proof_test(true, NELTS(inputs), inputs, NELTS(outputs), outputs, true));
+}
+