Add xchar support for write_escaped_string.

Signed-off-by: Vladislav Shchapov <vladislav@shchapov.ru>

test/ranges-test.cc

@@ -70,13 +70,9 @@ struct box {
   int value;
 };
 
-auto begin(const box& b) -> const int* {
-  return &b.value;
-}
+auto begin(const box& b) -> const int* { return &b.value; }
 
-auto end(const box& b) -> const int* {
-  return &b.value + 1;
-}
+auto end(const box& b) -> const int* { return &b.value + 1; }
 }  // namespace adl
 
 TEST(ranges_test, format_adl_begin_end) {
@@ -370,6 +366,7 @@ TEST(ranges_test, escape_string) {
     EXPECT_EQ(fmt::format("{}", vec{"\xf0\xaa\x9b\x9e"}), "[\"\\U0002a6de\"]");
     EXPECT_EQ(fmt::format("{}", vec{"\xf4\x8f\xbf\xc0"}),
               "[\"\\xf4\\x8f\\xbf\\xc0\"]");
+    EXPECT_EQ(fmt::format("{}", vec{"понедельник"}), "[\"понедельник\"]");
   }
 }
 

test/xchar-test.cc

@@ -337,6 +337,17 @@ TEST(xchar_test, ostream) {
 #endif
 }
 
+TEST(xchar_test, format_map) {
+  auto m = std::map<std::wstring, int>{{L"one", 1}, {L"t\"wo", 2}};
+  EXPECT_EQ(fmt::format(L"{}", m), L"{\"one\": 1, \"t\\\"wo\": 2}");
+}
+
+TEST(xchar_test, escape_string) {
+  using vec = std::vector<std::wstring>;
+  EXPECT_EQ(fmt::format(L"{}", vec{L"\n\r\t\"\\"}), L"[\"\\n\\r\\t\\\"\\\\\"]");
+  EXPECT_EQ(fmt::format(L"{}", vec{L"понедельник"}), L"[\"понедельник\"]");
+}
+
 TEST(xchar_test, to_wstring) { EXPECT_EQ(L"42", fmt::to_wstring(42)); }
 
 #ifndef FMT_STATIC_THOUSANDS_SEPARATOR