test: add unit test for non-standard txs with wrong nVersion

src/test/transaction_tests.cpp

@@ -713,6 +713,29 @@ BOOST_AUTO_TEST_CASE(test_IsStandard)
     t.vout[0].nValue = nDustThreshold;
     BOOST_CHECK(IsStandardTx(CTransaction(t), reason));
 
+    // Disallowed nVersion
+    t.nVersion = -1;
+    reason.clear();
+    BOOST_CHECK(!IsStandardTx(CTransaction(t), reason));
+    BOOST_CHECK_EQUAL(reason, "version");
+
+    t.nVersion = 0;
+    reason.clear();
+    BOOST_CHECK(!IsStandardTx(CTransaction(t), reason));
+    BOOST_CHECK_EQUAL(reason, "version");
+
+    t.nVersion = 3;
+    reason.clear();
+    BOOST_CHECK(!IsStandardTx(CTransaction(t), reason));
+    BOOST_CHECK_EQUAL(reason, "version");
+
+    // Allowed nVersion
+    t.nVersion = 1;
+    BOOST_CHECK(IsStandardTx(CTransaction(t), reason));
+
+    t.nVersion = 2;
+    BOOST_CHECK(IsStandardTx(CTransaction(t), reason));
+
     // Check dust with odd relay fee to verify rounding:
     // nDustThreshold = 182 * 3702 / 1000
     dustRelayFee = CFeeRate(3702);