Merge bitcoin/bitcoin#14752: tests: Unit tests for IsPayToWitnessScriptHash and IsWitnessProgram

bce9aaf31e2b0428e686e151324f8561ad71f11f Unit tests for IsWitnessProgram and IsP2WSH. (Daniel Kraft)

Pull request description:

  This adds basic unit tests for `CScript::IsPayToWitnessScriptHash` and `CScript::IsWitnessProgram`, similar to the existing tests for `CScript::IsPayToScriptHash`.  These tests are probably not super important given the other existing tests for segwit related code, but may be useful in catching some errors early.

  This implements #14737.

ACKs for top commit:
  aureleoules:
    tACK bce9aaf31e2b0428e686e151324f8561ad71f11f (`make check)`.

Tree-SHA512: 3cff5efc4ac53079289c72bfba8b1937bc103baadd32bb1fba41e78017f65f9cca17678c3202ad0711eae42b351d4132d9ed9b4e2dc07d138298691a09c4e822

2 files changed, 165 insertions, 0 deletions

diff --git a/src/Makefile.test.include b/src/Makefile.test.include
index e2e08468a7..a7505b9bcf 100644
--- a/src/Makefile.test.include
+++ b/src/Makefile.test.include
@@ -121,6 +121,7 @@ BITCOIN_TESTS =\
   test/scheduler_tests.cpp \
   test/script_p2sh_tests.cpp \
   test/script_parse_tests.cpp \
+  test/script_segwit_tests.cpp \
   test/script_standard_tests.cpp \
   test/script_tests.cpp \
   test/scriptnum10.h \
diff --git a/src/test/script_segwit_tests.cpp b/src/test/script_segwit_tests.cpp
new file mode 100644
index 0000000000..2bad59805f
--- /dev/null
+++ b/src/test/script_segwit_tests.cpp
@@ -0,0 +1,164 @@
+// Copyright (c) 2012-2021 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include <script/script.h>
+#include <test/util/setup_common.h>
+
+#include <boost/test/unit_test.hpp>
+
+BOOST_FIXTURE_TEST_SUITE(script_segwit_tests, BasicTestingSetup)
+
+BOOST_AUTO_TEST_CASE(IsPayToWitnessScriptHash_Valid)
+{
+    uint256 dummy;
+    CScript p2wsh;
+    p2wsh << OP_0 << ToByteVector(dummy);
+    BOOST_CHECK(p2wsh.IsPayToWitnessScriptHash());
+
+    std::vector<unsigned char> bytes = {OP_0, 32};
+    bytes.insert(bytes.end(), 32, 0);
+    BOOST_CHECK(CScript(bytes.begin(), bytes.end()).IsPayToWitnessScriptHash());
+}
+
+BOOST_AUTO_TEST_CASE(IsPayToWitnessScriptHash_Invalid_NotOp0)
+{
+    uint256 dummy;
+    CScript notp2wsh;
+    notp2wsh << OP_1 << ToByteVector(dummy);
+    BOOST_CHECK(!notp2wsh.IsPayToWitnessScriptHash());
+}
+
+BOOST_AUTO_TEST_CASE(IsPayToWitnessScriptHash_Invalid_Size)
+{
+    uint160 dummy;
+    CScript notp2wsh;
+    notp2wsh << OP_0 << ToByteVector(dummy);
+    BOOST_CHECK(!notp2wsh.IsPayToWitnessScriptHash());
+}
+
+BOOST_AUTO_TEST_CASE(IsPayToWitnessScriptHash_Invalid_Nop)
+{
+    uint256 dummy;
+    CScript notp2wsh;
+    notp2wsh << OP_0 << OP_NOP << ToByteVector(dummy);
+    BOOST_CHECK(!notp2wsh.IsPayToWitnessScriptHash());
+}
+
+BOOST_AUTO_TEST_CASE(IsPayToWitnessScriptHash_Invalid_EmptyScript)
+{
+    CScript notp2wsh;
+    BOOST_CHECK(!notp2wsh.IsPayToWitnessScriptHash());
+}
+
+BOOST_AUTO_TEST_CASE(IsPayToWitnessScriptHash_Invalid_Pushdata)
+{
+    // A script is not P2WSH if OP_PUSHDATA is used to push the hash.
+    std::vector<unsigned char> bytes = {OP_0, OP_PUSHDATA1, 32};
+    bytes.insert(bytes.end(), 32, 0);
+    BOOST_CHECK(!CScript(bytes.begin(), bytes.end()).IsPayToWitnessScriptHash());
+
+    bytes = {OP_0, OP_PUSHDATA2, 32, 0};
+    bytes.insert(bytes.end(), 32, 0);
+    BOOST_CHECK(!CScript(bytes.begin(), bytes.end()).IsPayToWitnessScriptHash());
+
+    bytes = {OP_0, OP_PUSHDATA4, 32, 0, 0, 0};
+    bytes.insert(bytes.end(), 32, 0);
+    BOOST_CHECK(!CScript(bytes.begin(), bytes.end()).IsPayToWitnessScriptHash());
+}
+
+namespace {
+
+bool IsExpectedWitnessProgram(const CScript& script, const int expectedVersion, const std::vector<unsigned char>& expectedProgram)
+{
+    int actualVersion;
+    std::vector<unsigned char> actualProgram;
+    if (!script.IsWitnessProgram(actualVersion, actualProgram)) {
+        return false;
+    }
+    BOOST_CHECK_EQUAL(actualVersion, expectedVersion);
+    BOOST_CHECK(actualProgram == expectedProgram);
+    return true;
+}
+
+bool IsNoWitnessProgram(const CScript& script)
+{
+    int dummyVersion;
+    std::vector<unsigned char> dummyProgram;
+    return !script.IsWitnessProgram(dummyVersion, dummyProgram);
+}
+
+} // anonymous namespace
+
+BOOST_AUTO_TEST_CASE(IsWitnessProgram_Valid)
+{
+    // Witness programs have a minimum data push of 2 bytes.
+    std::vector<unsigned char> program = {42, 18};
+    CScript wit;
+    wit << OP_0 << program;
+    BOOST_CHECK(IsExpectedWitnessProgram(wit, 0, program));
+
+    wit.clear();
+    // Witness programs have a maximum data push of 40 bytes.
+    program.resize(40);
+    wit << OP_16 << program;
+    BOOST_CHECK(IsExpectedWitnessProgram(wit, 16, program));
+
+    program.resize(32);
+    std::vector<unsigned char> bytes = {OP_5, static_cast<unsigned char>(program.size())};
+    bytes.insert(bytes.end(), program.begin(), program.end());
+    BOOST_CHECK(IsExpectedWitnessProgram(CScript(bytes.begin(), bytes.end()), 5, program));
+}
+
+BOOST_AUTO_TEST_CASE(IsWitnessProgram_Invalid_Version)
+{
+    std::vector<unsigned char> program(10);
+    CScript nowit;
+    nowit << OP_1NEGATE << program;
+    BOOST_CHECK(IsNoWitnessProgram(nowit));
+}
+
+BOOST_AUTO_TEST_CASE(IsWitnessProgram_Invalid_Size)
+{
+    std::vector<unsigned char> program(1);
+    CScript nowit;
+    nowit << OP_0 << program;
+    BOOST_CHECK(IsNoWitnessProgram(nowit));
+
+    nowit.clear();
+    program.resize(41);
+    nowit << OP_0 << program;
+    BOOST_CHECK(IsNoWitnessProgram(nowit));
+}
+
+BOOST_AUTO_TEST_CASE(IsWitnessProgram_Invalid_Nop)
+{
+    std::vector<unsigned char> program(10);
+    CScript nowit;
+    nowit << OP_0 << OP_NOP << program;
+    BOOST_CHECK(IsNoWitnessProgram(nowit));
+}
+
+BOOST_AUTO_TEST_CASE(IsWitnessProgram_Invalid_EmptyScript)
+{
+    CScript nowit;
+    BOOST_CHECK(IsNoWitnessProgram(nowit));
+}
+
+BOOST_AUTO_TEST_CASE(IsWitnessProgram_Invalid_Pushdata)
+{
+    // A script is no witness program if OP_PUSHDATA is used to push the hash.
+    std::vector<unsigned char> bytes = {OP_0, OP_PUSHDATA1, 32};
+    bytes.insert(bytes.end(), 32, 0);
+    BOOST_CHECK(IsNoWitnessProgram(CScript(bytes.begin(), bytes.end())));
+
+    bytes = {OP_0, OP_PUSHDATA2, 32, 0};
+    bytes.insert(bytes.end(), 32, 0);
+    BOOST_CHECK(IsNoWitnessProgram(CScript(bytes.begin(), bytes.end())));
+
+    bytes = {OP_0, OP_PUSHDATA4, 32, 0, 0, 0};
+    bytes.insert(bytes.end(), 32, 0);
+    BOOST_CHECK(IsNoWitnessProgram(CScript(bytes.begin(), bytes.end())));
+}
+
+BOOST_AUTO_TEST_SUITE_END()