Move fmt::fprintf to printf.h

test/printf-test.cc

@@ -479,3 +479,14 @@ TEST(PrintfTest, PrintfError) {
 TEST(PrintfTest, WideString) {
   EXPECT_EQ(L"abc", fmt::sprintf(L"%s", L"abc"));
 }
+
+TEST(PrintfTest, PrintfCustom) {
+  EXPECT_EQ("abc", fmt::sprintf("%s", TestString("abc")));
+}
+
+TEST(PrintfTest, OStream) {
+  std::ostringstream os;
+  int ret = fmt::fprintf(os, "Don't %s!", "panic");
+  EXPECT_EQ("Don't panic!", os.str());
+  EXPECT_EQ(12, ret);
+}