3 files changed, 32 insertions, 9 deletions
diff --git a/absl/strings/BUILD.bazel b/absl/strings/BUILD.bazel
index 2b194737..d6ce88da 100644
--- a/absl/strings/BUILD.bazel
+++ b/absl/strings/BUILD.bazel
@@ -404,7 +404,7 @@ cc_test(
 
 cc_test(
     name = "numbers_test",
-    size = "small",
+    size = "medium",
     srcs = [
         "internal/numbers_test_common.h",
         "numbers_test.cc",
@@ -628,7 +628,7 @@ cc_test(
 
 cc_test(
     name = "str_format_convert_test",
-    size = "small",
+    size = "medium",
     srcs = ["internal/str_format/convert_test.cc"],
     copts = ABSL_TEST_COPTS,
     visibility = ["//visibility:private"],
diff --git a/absl/strings/str_format.h b/absl/strings/str_format.h
index 539d9516..da3208e1 100644
--- a/absl/strings/str_format.h
+++ b/absl/strings/str_format.h
@@ -50,7 +50,7 @@
 //   * A `ParsedFormat` instance, which encapsulates a specific, pre-compiled
 //     format string for a specific set of type(s), and which can be passed
 //     between API boundaries. (The `FormatSpec` type should not be used
-//     directly.)
+//     directly except as an argument type for wrapper functions.)
 //
 // The `str_format` library provides the ability to output its format strings to
 // arbitrary sink types:
@@ -157,10 +157,15 @@ class FormatCountCapture {
 // FormatSpec
 //
 // The `FormatSpec` type defines the makeup of a format string within the
-// `str_format` library. You should not need to use or manipulate this type
-// directly. A `FormatSpec` is a variadic class template that is evaluated at
-// compile-time, according to the format string and arguments that are passed
-// to it.
+// `str_format` library. It is a variadic class template that is evaluated at
+// compile-time, according to the format string and arguments that are passed to
+// it.
+//
+// You should not need to manipulate this type directly. You should only name it
+// if you are writing wrapper functions which accept format arguments that will
+// be provided unmodified to functions in this library. Such a wrapper function
+// might be a class method that provides format arguments and/or internally uses
+// the result of formatting.
 //
 // For a `FormatSpec` to be valid at compile-time, it must be provided as
 // either:
diff --git a/absl/strings/str_format_test.cc b/absl/strings/str_format_test.cc
index d4cffa08..80830b36 100644
--- a/absl/strings/str_format_test.cc
+++ b/absl/strings/str_format_test.cc
@@ -13,7 +13,7 @@ namespace absl {
 namespace {
 using str_format_internal::FormatArgImpl;
 
-class FormatEntryPointTest : public ::testing::Test { };
+using FormatEntryPointTest = ::testing::Test;
 
 TEST_F(FormatEntryPointTest, Format) {
   std::string sink;
@@ -458,7 +458,7 @@ std::string SummarizeParsedFormat(const ParsedFormatBase& pc) {
   return out;
 }
 
-class ParsedFormatTest : public testing::Test {};
+using ParsedFormatTest = ::testing::Test;
 
 TEST_F(ParsedFormatTest, SimpleChecked) {
   EXPECT_EQ("[ABC]{d:1$d}[DEF]",
@@ -600,6 +600,24 @@ TEST_F(ParsedFormatTest, RegressionMixPositional) {
   EXPECT_FALSE((ExtendedParsedFormat<Conv::d, Conv::o>::New("%1$d %o")));
 }
 
+using FormatWrapperTest = ::testing::Test;
+
+// Plain wrapper for StrFormat.
+template <typename... Args>
+std::string WrappedFormat(const absl::FormatSpec<Args...>& format,
+                          const Args&... args) {
+  return StrFormat(format, args...);
+}
+
+TEST_F(FormatWrapperTest, ConstexprStringFormat) {
+  EXPECT_EQ(WrappedFormat("%s there", "hello"), "hello there");
+}
+
+TEST_F(FormatWrapperTest, ParsedFormat) {
+  ParsedFormat<'s'> format("%s there");
+  EXPECT_EQ(WrappedFormat(format, "hello"), "hello there");
+}
+
 }  // namespace
 }  // namespace absl