From dc970f4b74132d9636ef261c72326df05965d422 Mon Sep 17 00:00:00 2001
From: Fred Miller <fghzxm@outlook.com>
Date: Tue, 14 Jul 2020 23:56:55 +0800
Subject: [PATCH] Add test for user-defined types formatting

---
 test/CMakeLists.txt            |  1 +
 test/user-defined-type-test.cc | 43 ++++++++++++++++++++++++++++++++++
 2 files changed, 44 insertions(+)
 create mode 100644 test/user-defined-type-test.cc

diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index 89176633..6040e510 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -108,6 +108,7 @@ add_fmt_test(printf-test)
 add_fmt_test(custom-formatter-test)
 add_fmt_test(ranges-test)
 add_fmt_test(scan-test)
+add_fmt_test(user-defined-type-test)
 
 if (NOT MSVC_BUILD_STATIC)
   add_fmt_executable(posix-mock-test
diff --git a/test/user-defined-type-test.cc b/test/user-defined-type-test.cc
new file mode 100644
index 00000000..97d04d2b
--- /dev/null
+++ b/test/user-defined-type-test.cc
@@ -0,0 +1,43 @@
+#ifndef _CRT_SECURE_NO_WARNINGS
+#  define _CRT_SECURE_NO_WARNINGS
+#endif
+
+#include <algorithm>
+
+#include "fmt/format.h"
+#include "gtest-extra.h"
+
+enum struct color { red, green, blue };
+
+template <> struct fmt::formatter<color> {
+  constexpr auto parse(format_parse_context& ctx) {
+    auto it = ctx.begin();
+    if (it == ctx.end()) throw fmt::format_error("incomplete format string");
+    if (*it != '}') throw fmt::format_error("unknown format specs");
+    return it;
+  }
+  template <typename FormatContext> auto format(color c, FormatContext& ctx) {
+    static const char red_s[] = "red", green_s[] = "green", blue_s[] = "blue";
+    const char *begin_p, *end_p;
+    switch (c) {
+    case color::red:
+      begin_p = std::begin(red_s);
+      end_p = std::end(red_s);
+      break;
+    case color::green:
+      begin_p = std::begin(green_s);
+      end_p = std::end(green_s);
+      break;
+    case color::blue:
+      begin_p = std::begin(blue_s);
+      end_p = std::end(blue_s);
+      break;
+    }
+    return std::copy(begin_p, end_p - 1, ctx.out());
+  }
+};
+
+TEST(UserDefinedTypeTest, Format) {
+  EXPECT_EQ("red green blue",
+            fmt::format("{} {} {}", color::red, color::green, color::blue));
+}