Repository: bitcoin/bitcoin
File: src/test/util_string_tests.cpp (C++)

Code before:
// Copyright (c) 2024-present 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 <util/string.h>

#include <boost/test/unit_test.hpp>

using namespace util;

BOOST_AUTO_TEST_SUITE(util_string_tests)

// Helper to allow compile-time sanity checks while providing the number of
// args directly. Normally PassFmt<sizeof...(Args)> would be used.
template <unsigned NumArgs>
inline void PassFmt(util::ConstevalFormatString<NumArgs> fmt)
{
    // This was already executed at compile-time, but is executed again at run-time to avoid -Wunused.
    decltype(fmt)::Detail_CheckNumFormatSpecifiers(fmt.fmt);
}
template <unsigned WrongNumArgs>
inline void FailFmtWithError(std::string_view wrong_fmt, std::string_view error)
{
    using ErrType = const char*;
    auto check_throw{[error](const ErrType& str) { return str == error; }};
    BOOST_CHECK_EXCEPTION(util::ConstevalFormatString<WrongNumArgs>::Detail_CheckNumFormatSpecifiers(wrong_fmt), ErrType, check_throw);
}

BOOST_AUTO_TEST_CASE(ConstevalFormatString_NumSpec)
{
    PassFmt<0>("");
    PassFmt<0>("%%");
    PassFmt<1>("%s");
    PassFmt<0>("%%s");
    PassFmt<0>("s%%");
    PassFmt<1>("%%%s");
    PassFmt<1>("%s%%");
    PassFmt<0>(" 1$s");
    PassFmt<1>("%1$s");
    PassFmt<1>("%1$s%1$s");
    PassFmt<2>("%2$s");
    PassFmt<2>("%2$s 4$s %2$s");
    PassFmt<129>("%129$s 999$s %2$s");
    PassFmt<1>("%02d");
    PassFmt<1>("%+2s");
    PassFmt<1>("%.6i");
    PassFmt<1>("%5.2f");
    PassFmt<1>("%#x");

Review comment (bug):
Avoid extra allocations (from my [original diff](https://github.com/bitcoin/bitcoin/pull/30921#discussion_r1765022377)):
```suggestion
inline void FailFmtWithError(std::string_view wrong_fmt, const HasReason& error)
```

Code after:
// Copyright (c) 2024-present 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 <util/string.h>

#include <boost/test/unit_test.hpp>
#include <test/util/setup_common.h>

using namespace util;

BOOST_AUTO_TEST_SUITE(util_string_tests)

// Helper to allow compile-time sanity checks while providing the number of
// args directly. Normally PassFmt<sizeof...(Args)> would be used.
template <unsigned NumArgs>
inline void PassFmt(util::ConstevalFormatString<NumArgs> fmt)
{
    // This was already executed at compile-time, but is executed again at run-time to avoid -Wunused.
    decltype(fmt)::Detail_CheckNumFormatSpecifiers(fmt.fmt);
}
template <unsigned WrongNumArgs>
inline void FailFmtWithError(std::string_view wrong_fmt, std::string_view error)
{
    BOOST_CHECK_EXCEPTION(util::ConstevalFormatString<WrongNumArgs>::Detail_CheckNumFormatSpecifiers(wrong_fmt), const char*, HasReason(error));
}

BOOST_AUTO_TEST_CASE(ConstevalFormatString_NumSpec)
{
    PassFmt<0>("");
    PassFmt<0>("%%");
    PassFmt<1>("%s");
    PassFmt<0>("%%s");
    PassFmt<0>("s%%");
    PassFmt<1>("%%%s");
    PassFmt<1>("%s%%");
    PassFmt<0>(" 1$s");
    PassFmt<1>("%1$s");
    PassFmt<1>("%1$s%1$s");
    PassFmt<2>("%2$s");
    PassFmt<2>("%2$s 4$s %2$s");
    PassFmt<129>("%129$s 999$s %2$s");
    PassFmt<1>("%02d");
    PassFmt<1>("%+2s");
    PassFmt<1>("%.6i");
    PassFmt<1>("%5.2f");
    PassFmt<1>("%#x");
    PassFmt<1>("%1$5i");