const_init_immutable_string_test.cc

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#include "base/strings/const_init_immutable_string.h"

#include <string>
#include <string_view>

#include "testing/gunit.h"

namespace mozc::strings {
namespace {

constinit ConstInitImmutableString<256> g_value_simple_init(
    []() -> std::string { return "Mozc"; });

TEST(ConstInitImmutableStringTest, SimpleInit) {
  EXPECT_EQ(g_value_simple_init.GetOrInit(), "Mozc");
  EXPECT_EQ(g_value_simple_init.GetOrInit(), "Mozc");
}

TEST(ConstInitImmutableStringTest, NullTermination) {
  const auto value = g_value_simple_init.GetOrInit();
  EXPECT_EQ(value.data()[value.size()], '\0');
}

constexpr std::string_view kLongValue =
    "this string is longer than the inline buffer";

constinit ConstInitImmutableString<8> g_value_overflow([]() -> std::string {
  return std::string("this string is longer than the inline buffer");
});

TEST(ConstInitImmutableStringTest, HeapFallback) {
  const auto value = g_value_overflow.GetOrInit();
  EXPECT_EQ(value, kLongValue);
  EXPECT_EQ(value.data()[value.size()], '\0');
  // Repeated calls return the same pointer (stable storage).
  EXPECT_EQ(g_value_overflow.GetOrInit().data(), value.data());
}

constinit ConstInitImmutableString<256, wchar_t> g_value_wide(
    []() -> std::wstring { return L"WideMozc"; });

TEST(ConstInitImmutableStringTest, WideChar) {
  EXPECT_EQ(g_value_wide.GetOrInit(), std::wstring_view(L"WideMozc"));
  const auto value = g_value_wide.GetOrInit();
  EXPECT_EQ(value.data()[value.size()], L'\0');
}

}  // namespace
}  // namespace mozc::strings