[Bug]: Status matchers: no support for printing std::wstring

[phst]

Describe the issue

When matching a StatusOr<wstring> with IsOkAndHolds, Googletest won't print the actual string contents.

Steps to reproduce the problem

A Bazel workspace with:

MODULE.bazel:

bazel_dep(name = "rules_cc", version = "0.2.9")
bazel_dep(name = "googletest", version = "1.17.0.bcr.1")
bazel_dep(name = "abseil-cpp", version = "20250814.1")

BUILD.bazel:

load("@rules_cc//cc:cc_test.bzl", "cc_test")
cc_test(
    name = "test",
    srcs = ["test.cc"],
    deps = [
        "@abseil-cpp//absl/status:status_matchers",
        "@abseil-cpp//absl/status:statusor",
        "@googletest//:gtest",
        "@googletest//:gtest_main",
    ],
)

test.cc:

#include <string>

#include "absl/status/statusor.h"
#include "absl/status/status_matchers.h"
#include "gtest/gtest.h"

TEST(Test, WString) {
  EXPECT_THAT(std::wstring(L"foo"), testing::Eq(L"bar"));
  EXPECT_THAT(std::wstring(L"foo"), testing::Eq(std::wstring(L"bar")));
  EXPECT_THAT(absl::StatusOr<std::wstring>(std::wstring(L"foo")),
              absl_testing::IsOkAndHolds(L"bar"));
  EXPECT_THAT(absl::StatusOr<std::wstring>(std::wstring(L"foo")),
              absl_testing::IsOkAndHolds(std::wstring(L"bar")));
}

Running the test results in the following output:

Executing tests from //:test
-----------------------------------------------------------------------------
Running main() from gmock_main.cc
[==========] Running 1 test from 1 test suite.
[----------] Global test environment set-up.
[----------] 1 test from Test
[ RUN      ] Test.WString
test.cc:8: Failure
Value of: std::wstring(L"foo")
Expected: is equal to 0x100d23a10 pointing to L"bar"
  Actual: L"foo"

test.cc:9: Failure
Value of: std::wstring(L"foo")
Expected: is equal to L"bar"
  Actual: L"foo"

test.cc:11: Failure
Value of: absl::StatusOr<std::wstring>(std::wstring(L"foo"))
Expected: is OK and has a value that is equal to L"bar"
  Actual: 32-byte object <01-00 00-00 00-00 00-00 66-00 00-00 6F-00 00-00 6F-00 00-00 00-00 00-00 68-ED F2-00 01-00 00-03>

test.cc:13: Failure
Value of: absl::StatusOr<std::wstring>(std::wstring(L"foo"))
Expected: is OK and has a value that is equal to L"bar"
  Actual: 32-byte object <01-00 00-00 00-00 00-00 66-00 00-00 6F-00 00-00 6F-00 00-00 00-00 00-00 00-E9 94-80 01-00 00-03>

[  FAILED  ] Test.WString (0 ms)
[----------] 1 test from Test (0 ms total)

[----------] Global test environment tear-down
[==========] 1 test from 1 test suite ran. (0 ms total)
[  PASSED  ] 0 tests.
[  FAILED  ] 1 test, listed below:
[  FAILED  ] Test.WString

 1 FAILED TEST

Note that the normal string comparison (line 8 and 9) prints as expected, while the StatusOr check results in an unhelpful "Actual" message since apparently Googletest doesn't know how to print StatusOr<wstring>.

What version of Abseil are you using?

20250814.1

What operating system and version are you using?

macOS Tahoe

What compiler and version are you using?

Apple clang version 17.0.0 (clang-1700.3.19.1)
Target: arm64-apple-darwin25.0.0
Thread model: posix
InstalledDir: /Library/Developer/CommandLineTools/usr/bin

What build system are you using?

bazel 8.4.2

Additional context

No response

[phst]

Maybe AbslStringify/StrCat should accept std::wstring and convert it to UTF-8 like StrFormat does.