Add initial support for weekday formatting

test/unicode-test.cc

@@ -5,7 +5,25 @@
 //
 // For the license information refer to format.h.
 
-#include "fmt/core.h"
-#include "gtest/gtest.h"
+#include <vector>
 
-TEST(unicode_test, is_utf8) { EXPECT_TRUE(fmt::detail::is_utf8()); }
+#include "fmt/chrono.h"
+#include "gmock/gmock.h"
+#include "util.h"  // get_locale
+
+using testing::Contains;
+
+TEST(unicode_test, is_utf8) { EXPECT_TRUE(fmt::detail::is_utf8()); }
+
+TEST(unicode_test, legacy_locale) {
+  auto loc = get_locale("ru_RU.CP1251");
+  if (loc == std::locale::classic()) return;
+  try {
+    EXPECT_THAT(
+        (std::vector<std::string>{"День недели: пн", "День недели: Пн"}),
+        Contains(fmt::format(loc, "День недели: {:L}", fmt::weekday(1))));
+  } catch (const fmt::format_error& e) {
+    // Formatting can fail due to unsupported encoding.
+    fmt::print("Format error: {}\n", e.what());
+  }
+}