diff --git a/libcxx/test/std/utilities/format/format.functions/format.locale.pass.cpp b/libcxx/test/std/utilities/format/format.functions/P0645.format.locale.pass.cpp
rename from libcxx/test/std/utilities/format/format.functions/format.locale.pass.cpp
rename to libcxx/test/std/utilities/format/format.functions/P0645.format.locale.pass.cpp
--- a/libcxx/test/std/utilities/format/format.functions/format.locale.pass.cpp
+++ b/libcxx/test/std/utilities/format/format.functions/P0645.format.locale.pass.cpp
@@ -13,6 +13,10 @@
 
 // <format>
 
+// This tests the formatters introduced in the original paper P0645 and minor
+// improvements of this paper. The range based formatters are tested in the
+// P2286 tests.
+
 // template<class... Args>
 //   string format(const locale& loc, format-string<Args...> fmt, const Args&... args);
 // template<class... Args>
@@ -24,7 +28,7 @@
 #include <vector>
 
 #include "test_macros.h"
-#include "format_tests.h"
+#include "P0645.tests.h"
 #include "string_literal.h"
 #include "test_format_string.h"
 
diff --git a/libcxx/test/std/utilities/format/format.functions/format.locale.verify.cpp b/libcxx/test/std/utilities/format/format.functions/P0645.format.locale.verify.cpp
rename from libcxx/test/std/utilities/format/format.functions/format.locale.verify.cpp
rename to libcxx/test/std/utilities/format/format.functions/P0645.format.locale.verify.cpp
--- a/libcxx/test/std/utilities/format/format.functions/format.locale.verify.cpp
+++ b/libcxx/test/std/utilities/format/format.functions/P0645.format.locale.verify.cpp
@@ -13,6 +13,10 @@
 
 // <format>
 
+// This tests the formatters introduced in the original paper P0645 and minor
+// improvements of this paper. The range based formatters are tested in the
+// P2286 tests.
+
 // template<class... Args>
 //   string format(const locale& loc, format-string<Args...> fmt, const Args&... args);
 // template<class... Args>
diff --git a/libcxx/test/std/utilities/format/format.functions/format.pass.cpp b/libcxx/test/std/utilities/format/format.functions/P0645.format.pass.cpp
rename from libcxx/test/std/utilities/format/format.functions/format.pass.cpp
rename to libcxx/test/std/utilities/format/format.functions/P0645.format.pass.cpp
--- a/libcxx/test/std/utilities/format/format.functions/format.pass.cpp
+++ b/libcxx/test/std/utilities/format/format.functions/P0645.format.pass.cpp
@@ -16,6 +16,10 @@
 
 // <format>
 
+// This tests the formatters introduced in the original paper P0645 and minor
+// improvements of this paper. The range based formatters are tested in the
+// P2286 tests.
+
 // template<class... Args>
 //   string format(format-string<Args...> fmt, const Args&... args);
 // template<class... Args>
@@ -26,7 +30,7 @@
 #include <vector>
 
 #include "test_macros.h"
-#include "format_tests.h"
+#include "P0645.tests.h"
 #include "string_literal.h"
 #include "test_format_string.h"
 
diff --git a/libcxx/test/std/utilities/format/format.functions/format.verify.cpp b/libcxx/test/std/utilities/format/format.functions/P0645.format.verify.cpp
rename from libcxx/test/std/utilities/format/format.functions/format.verify.cpp
rename to libcxx/test/std/utilities/format/format.functions/P0645.format.verify.cpp
--- a/libcxx/test/std/utilities/format/format.functions/format.verify.cpp
+++ b/libcxx/test/std/utilities/format/format.functions/P0645.format.verify.cpp
@@ -12,6 +12,10 @@
 
 // <format>
 
+// This tests the formatters introduced in the original paper P0645 and minor
+// improvements of this paper. The range based formatters are tested in the
+// P2286 tests.
+
 // template<class... Args>
 //   string format(format-string<Args...> fmt, const Args&... args);
 // template<class... Args>
diff --git a/libcxx/test/std/utilities/format/format.functions/format_to.locale.pass.cpp b/libcxx/test/std/utilities/format/format.functions/P0645.format_to.locale.pass.cpp
rename from libcxx/test/std/utilities/format/format.functions/format_to.locale.pass.cpp
rename to libcxx/test/std/utilities/format/format.functions/P0645.format_to.locale.pass.cpp
--- a/libcxx/test/std/utilities/format/format.functions/format_to.locale.pass.cpp
+++ b/libcxx/test/std/utilities/format/format.functions/P0645.format_to.locale.pass.cpp
@@ -13,6 +13,10 @@
 
 // <format>
 
+// This tests the formatters introduced in the original paper P0645 and minor
+// improvements of this paper. The range based formatters are tested in the
+// P2286 tests.
+
 // template<class Out, class... Args>
 //   Out format_to(Out out, const locale& loc,
 //                 format-string<Args...> fmt, const Args&... args);
@@ -27,7 +31,7 @@
 #include <vector>
 
 #include "test_macros.h"
-#include "format_tests.h"
+#include "P0645.tests.h"
 #include "string_literal.h"
 #include "test_format_string.h"
 #include "test_iterators.h"
diff --git a/libcxx/test/std/utilities/format/format.functions/format_to.locale.verify.cpp b/libcxx/test/std/utilities/format/format.functions/P0645.format_to.locale.verify.cpp
rename from libcxx/test/std/utilities/format/format.functions/format_to.locale.verify.cpp
rename to libcxx/test/std/utilities/format/format.functions/P0645.format_to.locale.verify.cpp
--- a/libcxx/test/std/utilities/format/format.functions/format_to.locale.verify.cpp
+++ b/libcxx/test/std/utilities/format/format.functions/P0645.format_to.locale.verify.cpp
@@ -13,6 +13,10 @@
 
 // <format>
 
+// This tests the formatters introduced in the original paper P0645 and minor
+// improvements of this paper. The range based formatters are tested in the
+// P2286 tests.
+
 // template<class Out, class... Args>
 //   Out format_to(Out out, const locale& loc,
 //                 format-string<Args...> fmt, const Args&... args);
diff --git a/libcxx/test/std/utilities/format/format.functions/format_to.pass.cpp b/libcxx/test/std/utilities/format/format.functions/P0645.format_to.pass.cpp
rename from libcxx/test/std/utilities/format/format.functions/format_to.pass.cpp
rename to libcxx/test/std/utilities/format/format.functions/P0645.format_to.pass.cpp
--- a/libcxx/test/std/utilities/format/format.functions/format_to.pass.cpp
+++ b/libcxx/test/std/utilities/format/format.functions/P0645.format_to.pass.cpp
@@ -12,6 +12,10 @@
 
 // <format>
 
+// This tests the formatters introduced in the original paper P0645 and minor
+// improvements of this paper. The range based formatters are tested in the
+// P2286 tests.
+
 // template<class Out, class... Args>
 //   Out format_to(Out out, format-string<Args...> fmt, const Args&... args);
 // template<class Out, class... Args>
@@ -24,7 +28,7 @@
 #include <vector>
 
 #include "test_macros.h"
-#include "format_tests.h"
+#include "P0645.tests.h"
 #include "string_literal.h"
 #include "test_format_string.h"
 #include "test_iterators.h"
diff --git a/libcxx/test/std/utilities/format/format.functions/format_to.verify.cpp b/libcxx/test/std/utilities/format/format.functions/P0645.format_to.verify.cpp
rename from libcxx/test/std/utilities/format/format.functions/format_to.verify.cpp
rename to libcxx/test/std/utilities/format/format.functions/P0645.format_to.verify.cpp
--- a/libcxx/test/std/utilities/format/format.functions/format_to.verify.cpp
+++ b/libcxx/test/std/utilities/format/format.functions/P0645.format_to.verify.cpp
@@ -10,6 +10,10 @@
 
 // <format>
 
+// This tests the formatters introduced in the original paper P0645 and minor
+// improvements of this paper. The range based formatters are tested in the
+// P2286 tests.
+
 // Basic test to validate ill-formed code is properly detected.
 
 // template<class Out, class... Args>
diff --git a/libcxx/test/std/utilities/format/format.functions/format_to_n.locale.pass.cpp b/libcxx/test/std/utilities/format/format.functions/P0645.format_to_n.locale.pass.cpp
rename from libcxx/test/std/utilities/format/format.functions/format_to_n.locale.pass.cpp
rename to libcxx/test/std/utilities/format/format.functions/P0645.format_to_n.locale.pass.cpp
--- a/libcxx/test/std/utilities/format/format.functions/format_to_n.locale.pass.cpp
+++ b/libcxx/test/std/utilities/format/format.functions/P0645.format_to_n.locale.pass.cpp
@@ -13,6 +13,10 @@
 
 // <format>
 
+// This tests the formatters introduced in the original paper P0645 and minor
+// improvements of this paper. The range based formatters are tested in the
+// P2286 tests.
+
 // template<class Out, class... Args>
 //   format_to_n_result<Out> format_to_n(Out out, iter_difference_t<Out> n,
 //                                       const locale& loc, format-string<Args...> fmt,
@@ -29,7 +33,7 @@
 #include <vector>
 
 #include "test_macros.h"
-#include "format_tests.h"
+#include "P0645.tests.h"
 #include "string_literal.h"
 #include "test_format_string.h"
 
diff --git a/libcxx/test/std/utilities/format/format.functions/format_to_n.locale.verify.cpp b/libcxx/test/std/utilities/format/format.functions/P0645.format_to_n.locale.verify.cpp
rename from libcxx/test/std/utilities/format/format.functions/format_to_n.locale.verify.cpp
rename to libcxx/test/std/utilities/format/format.functions/P0645.format_to_n.locale.verify.cpp
--- a/libcxx/test/std/utilities/format/format.functions/format_to_n.locale.verify.cpp
+++ b/libcxx/test/std/utilities/format/format.functions/P0645.format_to_n.locale.verify.cpp
@@ -13,6 +13,10 @@
 
 // <format>
 
+// This tests the formatters introduced in the original paper P0645 and minor
+// improvements of this paper. The range based formatters are tested in the
+// P2286 tests.
+
 // template<class Out, class... Args>
 //   format_to_n_result<Out> format_to_n(Out out, iter_difference_t<Out> n,
 //                                       const locale& loc, format-string<Args...> fmt,
diff --git a/libcxx/test/std/utilities/format/format.functions/format_to_n.pass.cpp b/libcxx/test/std/utilities/format/format.functions/P0645.format_to_n.pass.cpp
rename from libcxx/test/std/utilities/format/format.functions/format_to_n.pass.cpp
rename to libcxx/test/std/utilities/format/format.functions/P0645.format_to_n.pass.cpp
--- a/libcxx/test/std/utilities/format/format.functions/format_to_n.pass.cpp
+++ b/libcxx/test/std/utilities/format/format.functions/P0645.format_to_n.pass.cpp
@@ -12,6 +12,10 @@
 
 // <format>
 
+// This tests the formatters introduced in the original paper P0645 and minor
+// improvements of this paper. The range based formatters are tested in the
+// P2286 tests.
+
 // template<class Out, class... Args>
 //   format_to_n_result<Out> format_to_n(Out out, iter_difference_t<Out> n,
 //                                       format-string<Args...> fmt, const Args&... args);
@@ -26,7 +30,7 @@
 #include <vector>
 
 #include "test_macros.h"
-#include "format_tests.h"
+#include "P0645.tests.h"
 #include "string_literal.h"
 #include "test_format_string.h"
 
diff --git a/libcxx/test/std/utilities/format/format.functions/format_to_n.verify.cpp b/libcxx/test/std/utilities/format/format.functions/P0645.format_to_n.verify.cpp
rename from libcxx/test/std/utilities/format/format.functions/format_to_n.verify.cpp
rename to libcxx/test/std/utilities/format/format.functions/P0645.format_to_n.verify.cpp
--- a/libcxx/test/std/utilities/format/format.functions/format_to_n.verify.cpp
+++ b/libcxx/test/std/utilities/format/format.functions/P0645.format_to_n.verify.cpp
@@ -12,6 +12,10 @@
 
 // <format>
 
+// This tests the formatters introduced in the original paper P0645 and minor
+// improvements of this paper. The range based formatters are tested in the
+// P2286 tests.
+
 // template<class Out, class... Args>
 //   format_to_n_result<Out> format_to_n(Out out, iter_difference_t<Out> n,
 //                                       format-string<Args...> fmt, const Args&... args);
diff --git a/libcxx/test/std/utilities/format/format.functions/formatted_size.locale.pass.cpp b/libcxx/test/std/utilities/format/format.functions/P0645.formatted_size.locale.pass.cpp
rename from libcxx/test/std/utilities/format/format.functions/formatted_size.locale.pass.cpp
rename to libcxx/test/std/utilities/format/format.functions/P0645.formatted_size.locale.pass.cpp
--- a/libcxx/test/std/utilities/format/format.functions/formatted_size.locale.pass.cpp
+++ b/libcxx/test/std/utilities/format/format.functions/P0645.formatted_size.locale.pass.cpp
@@ -13,6 +13,10 @@
 
 // <format>
 
+// This tests the formatters introduced in the original paper P0645 and minor
+// improvements of this paper. The range based formatters are tested in the
+// P2286 tests.
+
 // template<class... Args>
 //   size_t formatted_size(const locale& loc,
 //                         format-string<Args...> fmt, const Args&... args);
@@ -25,7 +29,7 @@
 #include <vector>
 
 #include "test_macros.h"
-#include "format_tests.h"
+#include "P0645.tests.h"
 #include "string_literal.h"
 #include "test_format_string.h"
 
diff --git a/libcxx/test/std/utilities/format/format.functions/formatted_size.locale.verify.cpp b/libcxx/test/std/utilities/format/format.functions/P0645.formatted_size.locale.verify.cpp
rename from libcxx/test/std/utilities/format/format.functions/formatted_size.locale.verify.cpp
rename to libcxx/test/std/utilities/format/format.functions/P0645.formatted_size.locale.verify.cpp
--- a/libcxx/test/std/utilities/format/format.functions/formatted_size.locale.verify.cpp
+++ b/libcxx/test/std/utilities/format/format.functions/P0645.formatted_size.locale.verify.cpp
@@ -13,6 +13,10 @@
 
 // <format>
 
+// This tests the formatters introduced in the original paper P0645 and minor
+// improvements of this paper. The range based formatters are tested in the
+// P2286 tests.
+
 // template<class... Args>
 //   size_t formatted_size(const locale& loc,
 //                         format-string<Args...> fmt, const Args&... args);
diff --git a/libcxx/test/std/utilities/format/format.functions/formatted_size.pass.cpp b/libcxx/test/std/utilities/format/format.functions/P0645.formatted_size.pass.cpp
rename from libcxx/test/std/utilities/format/format.functions/formatted_size.pass.cpp
rename to libcxx/test/std/utilities/format/format.functions/P0645.formatted_size.pass.cpp
--- a/libcxx/test/std/utilities/format/format.functions/formatted_size.pass.cpp
+++ b/libcxx/test/std/utilities/format/format.functions/P0645.formatted_size.pass.cpp
@@ -12,6 +12,10 @@
 
 // <format>
 
+// This tests the formatters introduced in the original paper P0645 and minor
+// improvements of this paper. The range based formatters are tested in the
+// P2286 tests.
+
 // template<class... Args>
 //   size_t formatted_size(format-string<Args...> fmt, const Args&... args);
 // template<class... Args>
@@ -22,7 +26,7 @@
 #include <vector>
 
 #include "test_macros.h"
-#include "format_tests.h"
+#include "P0645.tests.h"
 #include "string_literal.h"
 #include "test_format_string.h"
 
diff --git a/libcxx/test/std/utilities/format/format.functions/formatted_size.verify.cpp b/libcxx/test/std/utilities/format/format.functions/P0645.formatted_size.verify.cpp
rename from libcxx/test/std/utilities/format/format.functions/formatted_size.verify.cpp
rename to libcxx/test/std/utilities/format/format.functions/P0645.formatted_size.verify.cpp
--- a/libcxx/test/std/utilities/format/format.functions/formatted_size.verify.cpp
+++ b/libcxx/test/std/utilities/format/format.functions/P0645.formatted_size.verify.cpp
@@ -12,6 +12,10 @@
 
 // <format>
 
+// This tests the formatters introduced in the original paper P0645 and minor
+// improvements of this paper. The range based formatters are tested in the
+// P2286 tests.
+
 // template<class... Args>
 //   size_t formatted_size(format-string<Args...> fmt, const Args&... args);
 // template<class... Args>
diff --git a/libcxx/test/std/utilities/format/format.functions/format_tests.h b/libcxx/test/std/utilities/format/format.functions/P0645.tests.h
rename from libcxx/test/std/utilities/format/format.functions/format_tests.h
rename to libcxx/test/std/utilities/format/format.functions/P0645.tests.h
--- a/libcxx/test/std/utilities/format/format.functions/format_tests.h
+++ b/libcxx/test/std/utilities/format/format.functions/P0645.tests.h
@@ -5,10 +5,12 @@
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef TEST_STD_UTILITIES_FORMAT_FORMAT_FUNCTIONS_FORMAT_TESTS_H
-#define TEST_STD_UTILITIES_FORMAT_FORMAT_FUNCTIONS_FORMAT_TESTS_H
+#ifndef TEST_STD_UTILITIES_FORMAT_FORMAT_FUNCTIONS_P0645_TESTS_H
+#define TEST_STD_UTILITIES_FORMAT_FORMAT_FUNCTIONS_P0645_TESTS_H
 
-#include <format>
+// Contains the test for the formatters introduced in the original paper P0645
+// and minor improvements of this paper. The range based formatters are tested
+// in the P2286 tests.
 
 #include <algorithm>
 #include <cassert>
@@ -17,36 +19,14 @@
 #include <cstdint>
 #include <iterator>
 
-#include "make_string.h"
 #include "string_literal.h"
 #include "test_macros.h"
+#include "format.functions.common.h"
 
 // In this file the following template types are used:
 // TestFunction must be callable as check(expected-result, string-to-format, args-to-format...)
 // ExceptionTest must be callable as check_exception(expected-exception, string-to-format, args-to-format...)
 
-#define STR(S) MAKE_STRING(CharT, S)
-#define SV(S) MAKE_STRING_VIEW(CharT, S)
-#define CSTR(S) MAKE_CSTRING(CharT, S)
-
-template <class T>
-struct context {};
-
-template <>
-struct context<char> {
-  using type = std::format_context;
-};
-
-#ifndef TEST_HAS_NO_WIDE_CHARACTERS
-template <>
-struct context<wchar_t> {
-  using type = std::wformat_context;
-};
-#endif
-
-template <class T>
-using context_t = typename context<T>::type;
-
 // A user-defined type used to test the handle formatter.
 enum class status : uint16_t { foo = 0xAAAA, bar = 0x5555, foobar = 0xAA55 };
 
@@ -2868,4 +2848,4 @@
 }
 #endif
 
-#endif
+#endif // TEST_STD_UTILITIES_FORMAT_FORMAT_FUNCTIONS_P0645_TESTS_H
diff --git a/libcxx/test/std/utilities/format/format.functions/vformat.locale.pass.cpp b/libcxx/test/std/utilities/format/format.functions/P0645.vformat.locale.pass.cpp
rename from libcxx/test/std/utilities/format/format.functions/vformat.locale.pass.cpp
rename to libcxx/test/std/utilities/format/format.functions/P0645.vformat.locale.pass.cpp
--- a/libcxx/test/std/utilities/format/format.functions/vformat.locale.pass.cpp
+++ b/libcxx/test/std/utilities/format/format.functions/P0645.vformat.locale.pass.cpp
@@ -13,6 +13,10 @@
 
 // <format>
 
+// This tests the formatters introduced in the original paper P0645 and minor
+// improvements of this paper. The range based formatters are tested in the
+// P2286 tests.
+
 // string vformat(const locale& loc, string_view fmt, format_args args);
 // wstring vformat(const locale& loc, wstring_view fmt, wformat_args args);
 
@@ -21,7 +25,7 @@
 #include <vector>
 
 #include "test_macros.h"
-#include "format_tests.h"
+#include "P0645.tests.h"
 #include "string_literal.h"
 
 auto test = []<class CharT, class... Args>(
diff --git a/libcxx/test/std/utilities/format/format.functions/vformat.pass.cpp b/libcxx/test/std/utilities/format/format.functions/P0645.vformat.pass.cpp
rename from libcxx/test/std/utilities/format/format.functions/vformat.pass.cpp
rename to libcxx/test/std/utilities/format/format.functions/P0645.vformat.pass.cpp
--- a/libcxx/test/std/utilities/format/format.functions/vformat.pass.cpp
+++ b/libcxx/test/std/utilities/format/format.functions/P0645.vformat.pass.cpp
@@ -12,6 +12,10 @@
 
 // <format>
 
+// This tests the formatters introduced in the original paper P0645 and minor
+// improvements of this paper. The range based formatters are tested in the
+// P2286 tests.
+
 // string vformat(string_view fmt, format_args args);
 // wstring vformat(wstring_view fmt, wformat_args args);
 
@@ -20,8 +24,9 @@
 #include <vector>
 
 #include "test_macros.h"
-#include "format_tests.h"
+#include "P0645.tests.h"
 #include "string_literal.h"
+
 auto test = []<class CharT, class... Args>(
                 std::basic_string_view<CharT> expected, std::basic_string_view<CharT> fmt, Args&&... args) constexpr {
   std::basic_string<CharT> out = std::vformat(fmt, std::make_format_args<context_t<CharT>>(args...));
diff --git a/libcxx/test/std/utilities/format/format.functions/vformat_to.locale.pass.cpp b/libcxx/test/std/utilities/format/format.functions/P0645.vformat_to.locale.pass.cpp
rename from libcxx/test/std/utilities/format/format.functions/vformat_to.locale.pass.cpp
rename to libcxx/test/std/utilities/format/format.functions/P0645.vformat_to.locale.pass.cpp
--- a/libcxx/test/std/utilities/format/format.functions/vformat_to.locale.pass.cpp
+++ b/libcxx/test/std/utilities/format/format.functions/P0645.vformat_to.locale.pass.cpp
@@ -13,6 +13,10 @@
 
 // <format>
 
+// This tests the formatters introduced in the original paper P0645 and minor
+// improvements of this paper. The range based formatters are tested in the
+// P2286 tests.
+
 // template<class Out>
 //   Out vformat_to(Out out, const locale& loc, string_view fmt,
 //                  format_args args);
@@ -27,7 +31,7 @@
 #include <vector>
 
 #include "test_macros.h"
-#include "format_tests.h"
+#include "P0645.tests.h"
 #include "string_literal.h"
 
 auto test = []<class CharT, class... Args>(
diff --git a/libcxx/test/std/utilities/format/format.functions/vformat_to.pass.cpp b/libcxx/test/std/utilities/format/format.functions/P0645.vformat_to.pass.cpp
rename from libcxx/test/std/utilities/format/format.functions/vformat_to.pass.cpp
rename to libcxx/test/std/utilities/format/format.functions/P0645.vformat_to.pass.cpp
--- a/libcxx/test/std/utilities/format/format.functions/vformat_to.pass.cpp
+++ b/libcxx/test/std/utilities/format/format.functions/P0645.vformat_to.pass.cpp
@@ -12,6 +12,10 @@
 
 // <format>
 
+// This tests the formatters introduced in the original paper P0645 and minor
+// improvements of this paper. The range based formatters are tested in the
+// P2286 tests.
+
 // template<class Out>
 //   Out vformat_to(Out out, string_view fmt, format_args args);
 // template<class Out>
@@ -24,7 +28,7 @@
 #include <vector>
 
 #include "test_macros.h"
-#include "format_tests.h"
+#include "P0645.tests.h"
 #include "string_literal.h"
 
 auto test = []<class CharT, class... Args>(
diff --git a/libcxx/test/std/utilities/format/format.functions/format.functions.common.h b/libcxx/test/std/utilities/format/format.functions/format.functions.common.h
new file mode 100644
--- /dev/null
+++ b/libcxx/test/std/utilities/format/format.functions/format.functions.common.h
@@ -0,0 +1,39 @@
+//===----------------------------------------------------------------------===//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef TEST_STD_UTILITIES_FORMAT_FORMAT_FUNCTIONS_FORMAT_FUNCTIONS_COMMON_H
+#define TEST_STD_UTILITIES_FORMAT_FORMAT_FUNCTIONS_FORMAT_FUNCTIONS_COMMON_H
+
+// Contains the common part of the formatter tests for different papers.
+
+#include <format>
+
+#include "make_string.h"
+
+#define STR(S) MAKE_STRING(CharT, S)
+#define SV(S) MAKE_STRING_VIEW(CharT, S)
+#define CSTR(S) MAKE_CSTRING(CharT, S)
+
+template <class T>
+struct context {};
+
+template <>
+struct context<char> {
+  using type = std::format_context;
+};
+
+#ifndef TEST_HAS_NO_WIDE_CHARACTERS
+template <>
+struct context<wchar_t> {
+  using type = std::wformat_context;
+};
+#endif
+
+template <class T>
+using context_t = typename context<T>::type;
+
+#endif // TEST_STD_UTILITIES_FORMAT_FORMAT_FUNCTIONS_FORMAT_FUNCTIONS_COMMON_H
diff --git a/libcxx/test/std/utilities/format/format.functions/locale-specific_form.pass.cpp b/libcxx/test/std/utilities/format/format.functions/locale-specific_form.pass.cpp
--- a/libcxx/test/std/utilities/format/format.functions/locale-specific_form.pass.cpp
+++ b/libcxx/test/std/utilities/format/format.functions/locale-specific_form.pass.cpp
@@ -90,7 +90,7 @@
 #include "test_macros.h"
 #include "make_string.h"
 #include "platform_support.h" // locale name macros
-#include "format_tests.h"
+#include "P0645.tests.h"
 #include "string_literal.h"
 #include "test_format_string.h"