diff --git a/libcxx/test/std/input.output/filesystems/class.path/path.nonmember/path.factory.pass.cpp b/libcxx/test/std/input.output/filesystems/class.path/path.nonmember/path.factory.pass.cpp
--- a/libcxx/test/std/input.output/filesystems/class.path/path.nonmember/path.factory.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.path/path.nonmember/path.factory.pass.cpp
@@ -49,8 +49,7 @@
     path p = fs::u8path(In3, In3End);
     assert(p == In1);
   }
-#if TEST_STD_VER > 17 && defined(__cpp_char8_t) && defined(_LIBCPP_VERSION) && \
-    !defined(_LIBCPP_HAS_NO_LOCALIZATION)
+#if TEST_STD_VER > 17 && defined(__cpp_char8_t) && defined(_LIBCPP_VERSION) && !defined(TEST_HAS_NO_LOCALIZATION)
   const char8_t* u8In1 = u8"abcd/efg";
   const std::u8string u8In2(u8In1);
   const auto u8In3 = u8In2.begin();
diff --git a/libcxx/test/std/iterators/iterator.primitives/iterator.traits/cxx20_iterator_traits.compile.pass.cpp b/libcxx/test/std/iterators/iterator.primitives/iterator.traits/cxx20_iterator_traits.compile.pass.cpp
--- a/libcxx/test/std/iterators/iterator.primitives/iterator.traits/cxx20_iterator_traits.compile.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.primitives/iterator.traits/cxx20_iterator_traits.compile.pass.cpp
@@ -33,10 +33,10 @@
 #include <unordered_set>
 #include <vector>
 
-#ifndef _LIBCPP_HAS_NO_LOCALIZATION
-# include <regex>
-# include <ostream>
-# include <istream>
+#ifndef TEST_HAS_NO_LOCALIZATION
+#  include <regex>
+#  include <ostream>
+#  include <istream>
 #endif
 
 #ifndef _LIBCPP_HAS_NO_FILESYSTEM_LIBRARY
@@ -199,14 +199,14 @@
 static_assert(testIOIterator<std::insert_iterator<std::vector<int>>, std::output_iterator_tag>());
 static_assert(testConstWithoutConcept<std::istream_iterator<int, char>, int, std::input_iterator_tag>());
 
-#if !defined(_LIBCPP_HAS_NO_LOCALIZATION)
+#if !defined(TEST_HAS_NO_LOCALIZATION)
 static_assert(testWithoutConcept<std::istreambuf_iterator<char>, char, long long, char, char*, std::input_iterator_tag>());
 static_assert(testWithoutConcept<std::move_iterator<int*>, int, std::ptrdiff_t, int&&, int*, std::random_access_iterator_tag>());
 static_assert(testIOIterator<std::ostream_iterator<int, char>, std::output_iterator_tag>());
 static_assert(testIOIterator<std::ostreambuf_iterator<int, char>, std::output_iterator_tag>());
 static_assert(testConstWithoutConcept<std::cregex_iterator, std::cmatch, std::forward_iterator_tag>());
 static_assert(testConstWithoutConcept<std::cregex_token_iterator, std::csub_match, std::forward_iterator_tag>());
-#endif // !_LIBCPP_HAS_NO_LOCALIZATION
+#endif // !TEST_HAS_NO_LOCALIZATION
 
 #ifndef _LIBCPP_HAS_NO_FILESYSTEM_LIBRARY
 static_assert(testWithoutConcept<std::filesystem::directory_iterator, std::filesystem::directory_entry, std::ptrdiff_t,
diff --git a/libcxx/test/std/utilities/format/format.formatter/format.context/format.context/ctor.pass.cpp b/libcxx/test/std/utilities/format/format.formatter/format.context/format.context/ctor.pass.cpp
--- a/libcxx/test/std/utilities/format/format.formatter/format.context/format.context/ctor.pass.cpp
+++ b/libcxx/test/std/utilities/format/format.formatter/format.context/format.context/ctor.pass.cpp
@@ -72,12 +72,12 @@
     assert(output.size() == 1);
     assert(output.front() == CharT('a'));
 
-#ifndef _LIBCPP_HAS_NO_LOCALIZATION
+#ifndef TEST_HAS_NO_LOCALIZATION
     assert(context.locale() == std::locale());
 #endif
   }
 
-#ifndef _LIBCPP_HAS_NO_LOCALIZATION
+#ifndef TEST_HAS_NO_LOCALIZATION
   std::locale en_US{LOCALE_en_US_UTF_8};
   std::locale fr_FR{LOCALE_fr_FR_UTF_8};
   {
diff --git a/libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/formatter.floating_point.pass.cpp b/libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/formatter.floating_point.pass.cpp
--- a/libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/formatter.floating_point.pass.cpp
+++ b/libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/formatter.floating_point.pass.cpp
@@ -97,7 +97,7 @@
     buffer[size] = '0';
   }
   test_termination_condition(STR("025000.20000a}"), value, std::basic_string<CharT>{buffer.begin(), buffer.end()});
-#ifndef _LIBCPP_HAS_NO_LOCALIZATION
+#ifndef TEST_HAS_NO_LOCALIZATION
   end = std::to_chars(buffer.begin(), buffer.end(), value, std::chars_format::hex, 20'000).ptr;
   test_termination_condition(STR(".20000La}"), value, std::basic_string<CharT>{buffer.begin(), end});
 
@@ -137,7 +137,7 @@
     buffer[size] = '0';
   }
   test_termination_condition(STR("025000.20000A}"), value, std::basic_string<CharT>{buffer.begin(), buffer.end()});
-#ifndef _LIBCPP_HAS_NO_LOCALIZATION
+#ifndef TEST_HAS_NO_LOCALIZATION
   end = std::to_chars(buffer.begin(), buffer.end(), value, std::chars_format::hex, 20'000).ptr;
   std::transform(buffer.begin(), end, buffer.begin(), [](char c) { return std::toupper(c); });
   test_termination_condition(STR(".20000LA}"), value, std::basic_string<CharT>{buffer.begin(), end});
@@ -177,7 +177,7 @@
     buffer[size] = '0';
   }
   test_termination_condition(STR("025000.20000e}"), value, std::basic_string<CharT>{buffer.begin(), buffer.end()});
-#ifndef _LIBCPP_HAS_NO_LOCALIZATION
+#ifndef TEST_HAS_NO_LOCALIZATION
   end = std::to_chars(buffer.begin(), buffer.end(), value, std::chars_format::scientific, 20'000).ptr;
   test_termination_condition(STR(".20000Le}"), value, std::basic_string<CharT>{buffer.begin(), end});
 
@@ -217,7 +217,7 @@
     buffer[size] = '0';
   }
   test_termination_condition(STR("025000.20000E}"), value, std::basic_string<CharT>{buffer.begin(), buffer.end()});
-#ifndef _LIBCPP_HAS_NO_LOCALIZATION
+#ifndef TEST_HAS_NO_LOCALIZATION
   end = std::to_chars(buffer.begin(), buffer.end(), value, std::chars_format::scientific, 20'000).ptr;
   std::transform(buffer.begin(), end, buffer.begin(), [](char c) { return std::toupper(c); });
   test_termination_condition(STR(".20000LE}"), value, std::basic_string<CharT>{buffer.begin(), end});
@@ -257,7 +257,7 @@
     buffer[size] = '0';
   }
   test_termination_condition(STR("025000.20000f}"), value, std::basic_string<CharT>{buffer.begin(), buffer.end()});
-#ifndef _LIBCPP_HAS_NO_LOCALIZATION
+#ifndef TEST_HAS_NO_LOCALIZATION
   end = std::to_chars(buffer.begin(), buffer.end(), value, std::chars_format::fixed, 20'000).ptr;
   test_termination_condition(STR(".20000Lf}"), value, std::basic_string<CharT>{buffer.begin(), end});
 
@@ -297,7 +297,7 @@
     buffer[size] = '0';
   }
   test_termination_condition(STR("025000.20000F}"), value, std::basic_string<CharT>{buffer.begin(), buffer.end()});
-#ifndef _LIBCPP_HAS_NO_LOCALIZATION
+#ifndef TEST_HAS_NO_LOCALIZATION
   end = std::to_chars(buffer.begin(), buffer.end(), value, std::chars_format::fixed, 20'000).ptr;
   std::transform(buffer.begin(), end, buffer.begin(), [](char c) { return std::toupper(c); });
   test_termination_condition(STR(".20000LF}"), value, std::basic_string<CharT>{buffer.begin(), end});
@@ -337,7 +337,7 @@
     buffer[size] = '0';
   }
   test_termination_condition(STR("025000.20000g}"), value, std::basic_string<CharT>{buffer.begin(), buffer.end()});
-#ifndef _LIBCPP_HAS_NO_LOCALIZATION
+#ifndef TEST_HAS_NO_LOCALIZATION
   end = std::to_chars(buffer.begin(), buffer.end(), value, std::chars_format::general, 20'000).ptr;
   test_termination_condition(STR(".20000Lg}"), value, std::basic_string<CharT>{buffer.begin(), end});
 
@@ -377,7 +377,7 @@
     buffer[size] = '0';
   }
   test_termination_condition(STR("025000.20000G}"), value, std::basic_string<CharT>{buffer.begin(), buffer.end()});
-#ifndef _LIBCPP_HAS_NO_LOCALIZATION
+#ifndef TEST_HAS_NO_LOCALIZATION
   end = std::to_chars(buffer.begin(), buffer.end(), value, std::chars_format::general, 20'000).ptr;
   std::transform(buffer.begin(), end, buffer.begin(), [](char c) { return std::toupper(c); });
   test_termination_condition(STR(".20000LG}"), value, std::basic_string<CharT>{buffer.begin(), end});
diff --git a/libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/types.compile.pass.cpp b/libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/types.compile.pass.cpp
--- a/libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/types.compile.pass.cpp
+++ b/libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/types.compile.pass.cpp
@@ -33,7 +33,7 @@
 #include <map>
 #include <optional>
 #include <queue>
-#ifndef _LIBCPP_HAS_NO_LOCALIZATION
+#ifndef TEST_HAS_NO_LOCALIZATION
 #  include <regex>
 #endif
 #include <set>
@@ -213,7 +213,7 @@
   assert_formatter_is_disabled<std::filesystem::path, CharT>();
 #endif
   assert_formatter_is_disabled<std::shared_ptr<int>, CharT>();
-#ifndef _LIBCPP_HAS_NO_LOCALIZATION
+#ifndef TEST_HAS_NO_LOCALIZATION
   assert_formatter_is_disabled<std::sub_match<CharT*>, CharT>();
 #endif
 #ifndef _LIBCPP_HAS_NO_THREADS
diff --git a/libcxx/test/std/utilities/format/format.functions/format.pass.cpp b/libcxx/test/std/utilities/format/format.functions/format.pass.cpp
--- a/libcxx/test/std/utilities/format/format.functions/format.pass.cpp
+++ b/libcxx/test/std/utilities/format/format.functions/format.pass.cpp
@@ -24,7 +24,7 @@
 
 #include <format>
 #include <cassert>
-#ifndef _LIBCPP_HAS_NO_LOCALIZATION
+#ifndef TEST_HAS_NO_LOCALIZATION
 #  include <iostream>
 #endif
 #include <vector>
@@ -35,7 +35,7 @@
 auto test = []<class CharT, class... Args>(std::basic_string_view<CharT> expected, std::basic_string_view<CharT> fmt,
                                            const Args&... args) {
   std::basic_string<CharT> out = std::format(fmt, args...);
-#ifndef _LIBCPP_HAS_NO_LOCALIZATION
+#ifndef TEST_HAS_NO_LOCALIZATION
   if constexpr (std::same_as<CharT, char>)
     if (out != expected)
       std::cerr << "\nFormat string   " << fmt << "\nExpected output " << expected << "\nActual output   " << out
@@ -49,13 +49,13 @@
 #ifndef TEST_HAS_NO_EXCEPTIONS
   try {
     std::format(fmt, args...);
-#  ifndef _LIBCPP_HAS_NO_LOCALIZATION
+#  ifndef TEST_HAS_NO_LOCALIZATION
     if constexpr (std::same_as<CharT, char>)
       std::cerr << "\nFormat string   " << fmt << "\nDidn't throw an exception.\n";
 #  endif
     assert(false);
   } catch (const std::format_error& e) {
-#  if defined(_LIBCPP_VERSION) && !defined(_LIBCPP_HAS_NO_LOCALIZATION)
+#  if defined(_LIBCPP_VERSION) && !defined(TEST_HAS_NO_LOCALIZATION)
     if constexpr (std::same_as<CharT, char>)
       if (e.what() != what)
         std::cerr << "\nFormat string   " << fmt << "\nExpected exception " << what << "\nActual exception   "
diff --git a/libcxx/test/support/test_macros.h b/libcxx/test/support/test_macros.h
--- a/libcxx/test/support/test_macros.h
+++ b/libcxx/test/support/test_macros.h
@@ -376,6 +376,10 @@
 #   define TEST_HAS_NO_UNICODE_CHARS
 #endif
 
+#if define(_LIBCPP_HAS_NO_LOCALIZATION)
+#  define TEST_HAS_NO_LOCALIZATION
+#endif
+
 #if defined(__GNUC__)
 #pragma GCC diagnostic pop
 #endif