src/utils/numeric_test.cc

// Copyright 2026 The Dawn & Tint Authors
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#include "src/utils/numeric.h"

#include <gtest/gtest.h>

#include "src/utils/typed_integer.h"

namespace dawn {
namespace {

// Death tests
// Name "*DeathTest" per https://google.github.io/googletest/advanced.html#death-test-naming

// Test for checked cast between various types.
template <typename T32, typename T64>
void CheckedCastTest() {
    using I32 = UnderlyingType<T32>;
    using I64 = UnderlyingType<T64>;
    static_assert(std::is_same_v<I32, uint32_t>);
    static_assert(std::is_same_v<I64, uint64_t>);

    // No-ops
    checked_cast<T32>(T32{std::numeric_limits<I32>::max()});
    checked_cast<T64>(T64{std::numeric_limits<I64>::max()});

    // Widening
    checked_cast<T64>(T32{std::numeric_limits<I32>::max()});

    // Narrowing
    EXPECT_DEATH(checked_cast<T32>(T64{uint64_t{std::numeric_limits<I32>::max()} + 1}), "");
    EXPECT_DEATH(checked_cast<T32>(T64{uint64_t{std::numeric_limits<I32>::max()} * 2}), "");
    EXPECT_DEATH(checked_cast<T32>(T64{std::numeric_limits<uint64_t>::max()}), "");
}

TEST(NumericDeathTest, CheckedCast) {
    CheckedCastTest<uint32_t, uint64_t>();

    using TypedU32 = TypedInteger<struct TypedU32T, uint32_t>;
    using TypedU64 = TypedInteger<struct TypedU64T, uint64_t>;
    CheckedCastTest<uint32_t, TypedU64>();
    CheckedCastTest<TypedU32, uint64_t>();
    CheckedCastTest<TypedU32, TypedU64>();

    enum class EnumU32 : uint32_t {};
    enum class EnumU64 : uint64_t {};
    CheckedCastTest<uint32_t, EnumU64>();
    CheckedCastTest<EnumU32, uint64_t>();
    CheckedCastTest<EnumU32, EnumU64>();
}

}  // anonymous namespace
}  // namespace dawn