Function TestFromHex

src/test/uint256_tests.cpp:249–287

 */
template <typename T>
void TestFromHex()
{
    constexpr unsigned int num_chars{T::size() * 2};
    static_assert(num_chars <= 64); // this test needs to be modified to allow for more than 64 hex chars
    const std::string valid_64char_input{"0123456789abcdef0123456789ABCDEF0123456789abcdef0123456789ABCDEF"};
    const auto valid_input{valid_64char_input.substr(0, num_chars)};
    {
        // check that lower and upper case hex characters are accepted
        auto valid_result{T::FromHex(valid_input)};
        BOOST_REQUIRE(valid_result);
        BOOST_CHECK_EQUAL(valid_result->ToString(), ToLower(valid_input));
    }
    {
        // check that only strings of size num_chars are accepted
        BOOST_CHECK(!T::FromHex(""));
        BOOST_CHECK(!T::FromHex("0"));
        BOOST_CHECK(!T::FromHex(valid_input.substr(0, num_chars / 2)));
        BOOST_CHECK(!T::FromHex(valid_input.substr(0, num_chars - 1)));
        BOOST_CHECK(!T::FromHex(valid_input + "0"));
    }
    {
        // check that non-hex characters are not accepted
        std::string invalid_chars{R"( !"#$%&'()*+,-./:;<=>?@GHIJKLMNOPQRSTUVWXYZ[\]^_`ghijklmnopqrstuvwxyz{|}~)"};
        for (auto c : invalid_chars) {
            BOOST_CHECK(!T::FromHex(valid_input.substr(0, num_chars - 1) + c));
        }
        // 0x prefixes are invalid
        std::string invalid_prefix{"0x" + valid_input};
        BOOST_CHECK(!T::FromHex(std::string_view(invalid_prefix.data(), num_chars)));
        BOOST_CHECK(!T::FromHex(invalid_prefix));
    }
    {
        // check that string_view length is respected
        std::string chars_68{valid_64char_input + "0123"};
        BOOST_CHECK_EQUAL(T::FromHex(std::string_view(chars_68.data(), num_chars)).value().ToString(), ToLower(valid_input));
        BOOST_CHECK(!T::FromHex(std::string_view(chars_68.data(), num_chars - 1))); // too short
        BOOST_CHECK(!T::FromHex(std::string_view(chars_68.data(), num_chars + 1))); // too long
    }
}

BOOST_AUTO_TEST_CASE(from_hex)
{