Improve POSIX API detection

test/gtest-extra.h

@@ -10,16 +10,7 @@
 
 #include <string>
 #include "gmock.h"
-
-#include "fmt/core.h"
-
-#ifndef FMT_USE_FILE_DESCRIPTORS
-#  define FMT_USE_FILE_DESCRIPTORS 0
-#endif
-
-#if FMT_USE_FILE_DESCRIPTORS
-#  include "fmt/posix.h"
-#endif
+#include "fmt/posix.h"
 
 #define FMT_TEST_THROW_(statement, expected_exception, expected_message, fail) \
   GTEST_AMBIGUOUS_ELSE_BLOCKER_                                                \
@@ -65,7 +56,7 @@ std::string format_system_error(int error_code, fmt::string_view message);
   EXPECT_THROW_MSG(statement, fmt::system_error,            \
                    format_system_error(error_code, message))
 
-#if FMT_USE_FILE_DESCRIPTORS
+#if FMT_USE_FCNTL
 
 // Captures file output by redirecting it to a pipe.
 // The output it can handle is limited by the pipe capacity.
@@ -151,7 +142,9 @@ std::string read(fmt::file& f, std::size_t count);
 #  define EXPECT_READ(file, expected_content) \
     EXPECT_EQ(expected_content, read(file, std::strlen(expected_content)))
 
-#endif  // FMT_USE_FILE_DESCRIPTORS
+#else
+#  define EXPECT_WRITE(file, statement, expected_output) SUCCEED()
+#endif  // FMT_USE_FCNTL
 
 template <typename Mock> struct ScopedMock : testing::StrictMock<Mock> {
   ScopedMock() { Mock::instance = this; }