Merge #17299: test: add reason checks for non-standard txs in test_IsStandard

c1c6c41 test: add reason checks for non-standard txs in test_IsStandard (Sebastian Falbesoner)

Pull request description:

  While taking a look at #17272 I noticed that for some reason the unit test `test_IsStandard` (which was not adapted to the policy change in the referenced PR commits) didn't fail as expected:
  https://github.com/bitcoin/bitcoin/blob/6a97e8a060f7632bbaee27d3de8035dc6ebe3895/src/test/transaction_tests.cpp#L758-L762
  It turned out that `IsStandardTx()` returned `"dust"` as rejection reason (instead of the expected `"multi-op-return"`), leading to the conclusion that bitcoin/bitcoin@5fe6f05 erroneously performs the `IsDust()` check also for TX_NULL_DATA transactions. To avoid cases like this in the future, this PR makes the unit test `test_IsStandard` more strict by also checking for the concrete reason after each occurence of `IsStandardTx()` returning false.

ACKs for top commit:
  instagibbs:
    utACK bitcoin/bitcoin@c1c6c41

Tree-SHA512: c7419884cc52977c73f8f8c476eaebed80ba7bda4d03509d3f46dd977be911389f7b53daefa5ef31d2f7df9402243152e01e83f1b8a9fb300c19d1a0f69a89a9

Author: MarcoFalke

src/test/transaction_tests.cpp

@@ -706,7 +706,9 @@ BOOST_AUTO_TEST_CASE(test_IsStandard)
     BOOST_CHECK_EQUAL(nDustThreshold, 546);
     // dust:
     t.vout[0].nValue = nDustThreshold - 1;
+    reason.clear();
     BOOST_CHECK(!IsStandardTx(CTransaction(t), reason));
+    BOOST_CHECK_EQUAL(reason, "dust");
     // not dust:
     t.vout[0].nValue = nDustThreshold;
     BOOST_CHECK(IsStandardTx(CTransaction(t), reason));
@@ -716,14 +718,18 @@ BOOST_AUTO_TEST_CASE(test_IsStandard)
     dustRelayFee = CFeeRate(3702);
     // dust:
     t.vout[0].nValue = 673 - 1;
+    reason.clear();
     BOOST_CHECK(!IsStandardTx(CTransaction(t), reason));
+    BOOST_CHECK_EQUAL(reason, "dust");
     // not dust:
     t.vout[0].nValue = 673;
     BOOST_CHECK(IsStandardTx(CTransaction(t), reason));
     dustRelayFee = CFeeRate(DUST_RELAY_TX_FEE);
 
     t.vout[0].scriptPubKey = CScript() << OP_1;
+    reason.clear();
     BOOST_CHECK(!IsStandardTx(CTransaction(t), reason));
+    BOOST_CHECK_EQUAL(reason, "scriptpubkey");
 
     // MAX_OP_RETURN_RELAY-byte TX_NULL_DATA (standard)
     t.vout[0].scriptPubKey = CScript() << OP_RETURN << ParseHex("04678afdb0fe5548271967f1a67130b7105cd6a828e03909a67962e0ea1f61deb649f6bc3f4cef3804678afdb0fe5548271967f1a67130b7105cd6a828e03909a67962e0ea1f61deb649f6bc3f4cef38");
@@ -733,7 +739,9 @@ BOOST_AUTO_TEST_CASE(test_IsStandard)
     // MAX_OP_RETURN_RELAY+1-byte TX_NULL_DATA (non-standard)
     t.vout[0].scriptPubKey = CScript() << OP_RETURN << ParseHex("04678afdb0fe5548271967f1a67130b7105cd6a828e03909a67962e0ea1f61deb649f6bc3f4cef3804678afdb0fe5548271967f1a67130b7105cd6a828e03909a67962e0ea1f61deb649f6bc3f4cef3800");
     BOOST_CHECK_EQUAL(MAX_OP_RETURN_RELAY + 1, t.vout[0].scriptPubKey.size());
+    reason.clear();
     BOOST_CHECK(!IsStandardTx(CTransaction(t), reason));
+    BOOST_CHECK_EQUAL(reason, "scriptpubkey");
 
     // Data payload can be encoded in any way...
     t.vout[0].scriptPubKey = CScript() << OP_RETURN << ParseHex("");
@@ -748,7 +756,9 @@ BOOST_AUTO_TEST_CASE(test_IsStandard)
 
     // ...so long as it only contains PUSHDATA's
     t.vout[0].scriptPubKey = CScript() << OP_RETURN << OP_RETURN;
+    reason.clear();
     BOOST_CHECK(!IsStandardTx(CTransaction(t), reason));
+    BOOST_CHECK_EQUAL(reason, "scriptpubkey");
 
     // TX_NULL_DATA w/o PUSHDATA
     t.vout.resize(1);
@@ -759,15 +769,21 @@ BOOST_AUTO_TEST_CASE(test_IsStandard)
     t.vout.resize(2);
     t.vout[0].scriptPubKey = CScript() << OP_RETURN << ParseHex("04678afdb0fe5548271967f1a67130b7105cd6a828e03909a67962e0ea1f61deb649f6bc3f4cef38");
     t.vout[1].scriptPubKey = CScript() << OP_RETURN << ParseHex("04678afdb0fe5548271967f1a67130b7105cd6a828e03909a67962e0ea1f61deb649f6bc3f4cef38");
+    reason.clear();
     BOOST_CHECK(!IsStandardTx(CTransaction(t), reason));
+    BOOST_CHECK_EQUAL(reason, "multi-op-return");
 
     t.vout[0].scriptPubKey = CScript() << OP_RETURN << ParseHex("04678afdb0fe5548271967f1a67130b7105cd6a828e03909a67962e0ea1f61deb649f6bc3f4cef38");
     t.vout[1].scriptPubKey = CScript() << OP_RETURN;
+    reason.clear();
     BOOST_CHECK(!IsStandardTx(CTransaction(t), reason));
+    BOOST_CHECK_EQUAL(reason, "multi-op-return");
 
     t.vout[0].scriptPubKey = CScript() << OP_RETURN;
     t.vout[1].scriptPubKey = CScript() << OP_RETURN;
+    reason.clear();
     BOOST_CHECK(!IsStandardTx(CTransaction(t), reason));
+    BOOST_CHECK_EQUAL(reason, "multi-op-return");
 }
 
 BOOST_AUTO_TEST_SUITE_END()