diff --git a/test/format-test.cc b/test/format-test.cc
index fe7ebb03..db5d6a29 100644
--- a/test/format-test.cc
+++ b/test/format-test.cc
@@ -1587,7 +1587,7 @@ TEST(FormatterTest, FormatExamples) {
 
   EXPECT_THROW({
     const char *filename = "nonexistent";
-    FILE *f = fopen(filename, "r");
+    FILE *f = std::fopen(filename, "r");
     if (!f)
       fmt::ThrowSystemError(errno, "Cannot open file '{}'") << filename;
   }, fmt::SystemError);
@@ -1669,26 +1669,34 @@ TEST(FormatterTest, OutputNotWrittenOnError) {
   EXPECT_EQ(0, num_writes);
 }
 
+#if FMT_USE_FILE_DESCRIPTORS
+
 TEST(FormatterTest, FileSink) {
-  FILE *f = std::fopen("out", "w");
-  fmt::FileSink fs(f);
-  fs(Writer() << "test");
-  std::fclose(f);
-  EXPECT_EQ("test", ReadFile("out"));
+  File read_end, write_end;
+  File::pipe(read_end, write_end);
+  BufferedFile f = write_end.fdopen("w");
+  EXPECT_WRITE(f.get(), {
+    fmt::FileSink fs(f.get());
+    fs(Writer() << "test");
+  }, "test");
 }
 
 TEST(FormatterTest, FileSinkWriteError) {
-  FILE *f = std::fopen("out", "r");
-  fmt::FileSink fs(f);
-  int result = std::fwrite(" ", 1, 1, f);
+  File read_end, write_end;
+  File::pipe(read_end, write_end);
+  BufferedFile f = read_end.fdopen("r");
+  fmt::FileSink fs(f.get());
+  int result = std::fwrite(" ", 1, 1, f.get());
   int error_code = errno;
   EXPECT_EQ(0, result);
-  std::string error_message =
-      str(Format("{}: {}") << "cannot write to file" << strerror(error_code));
-  EXPECT_THROW_MSG(fs(Writer() << "test"), fmt::SystemError, error_message);
-  std::fclose(f);
+  EXPECT_SYSTEM_ERROR(
+      fs(Writer() << "test"), error_code, "cannot write to file");
 }
 
+#else
+# pragma message "warning: some tests are disabled"
+#endif
+
 // The test doesn't compile on older compilers which follow C++03 and
 // require an accessible copy constructor when binding a temporary to
 // a const reference.
@@ -1812,7 +1820,7 @@ TEST(FormatIntTest, FormatDec) {
   EXPECT_EQ("42", FormatDec(42ull));
 }
 
-#ifdef FMT_USE_FILE_DESCRIPTORS
+#if FMT_USE_FILE_DESCRIPTORS
 
 TEST(FormatTest, PrintColored) {
   EXPECT_WRITE(stdout, fmt::PrintColored(fmt::RED, "Hello, {}!\n") << "world",
diff --git a/test/gtest-extra-test.cc b/test/gtest-extra-test.cc
index 56701c06..a2a5d63e 100644
--- a/test/gtest-extra-test.cc
+++ b/test/gtest-extra-test.cc
@@ -39,12 +39,6 @@
 
 namespace {
 
-std::string FormatSystemErrorMessage(int error_code, fmt::StringRef message) {
-  fmt::Writer out;
-  fmt::internal::FormatSystemErrorMessage(out, error_code, message);
-  return str(out);
-}
-
 // Suppresses Windows assertions on invalid file descriptors, making
 // POSIX functions return proper error codes instead of crashing on Windows.
 class SuppressAssert {
@@ -70,26 +64,9 @@ class SuppressAssert {
 
 #define SUPPRESS_ASSERT(statement) { SuppressAssert sa; statement; }
 
-#define EXPECT_SYSTEM_ERROR(statement, error_code, message) \
-  EXPECT_THROW_MSG(statement, fmt::SystemError, \
-      FormatSystemErrorMessage(error_code, message))
-
 #define EXPECT_SYSTEM_ERROR_NOASSERT(statement, error_code, message) \
   EXPECT_SYSTEM_ERROR(SUPPRESS_ASSERT(statement), error_code, message)
 
-// Checks if the file is open by reading one character from it.
-bool IsOpen(int fd) {
-  char buffer;
-  return FMT_POSIX(read(fd, &buffer, 1)) == 1;
-}
-
-bool IsClosed(int fd) {
-  char buffer;
-  std::streamsize result = 0;
-  SUPPRESS_ASSERT(result = FMT_POSIX(read(fd, &buffer, 1)));
-  return result == -1 && errno == EBADF;
-}
-
 // Tests that assertion macros evaluate their arguments exactly once.
 class SingleEvaluationTest : public ::testing::Test {
  protected:
@@ -265,6 +242,19 @@ TEST(StreamingAssertionsTest, EXPECT_WRITE) {
 
 #if FMT_USE_FILE_DESCRIPTORS
 
+// Checks if the file is open by reading one character from it.
+bool IsOpen(int fd) {
+  char buffer;
+  return FMT_POSIX(read(fd, &buffer, 1)) == 1;
+}
+
+bool IsClosed(int fd) {
+  char buffer;
+  std::streamsize result = 0;
+  SUPPRESS_ASSERT(result = FMT_POSIX(read(fd, &buffer, 1)));
+  return result == -1 && errno == EBADF;
+}
+
 TEST(ErrorCodeTest, Ctor) {
   EXPECT_EQ(0, ErrorCode().get());
   EXPECT_EQ(42, ErrorCode(42).get());
@@ -671,6 +661,7 @@ TEST(OutputRedirectTest, ErrorInDtor) {
   write_dup.dup2(write_fd); // "undo" close or dtor of BufferedFile will fail
 }
 
+// TODO: test EXPECT_SYSTEM_ERROR
 // TODO: test retry on EINTR
 
 #endif  // FMT_USE_FILE_DESCRIPTORS
diff --git a/test/gtest-extra.cc b/test/gtest-extra.cc
index 503a9cb4..c0f28e6a 100644
--- a/test/gtest-extra.cc
+++ b/test/gtest-extra.cc
@@ -78,7 +78,7 @@ File::File(const char *path, int oflag) {
 }
 
 File::~File() FMT_NOEXCEPT(true) {
-  // Don't need to retry close in case of EINTR.
+  // Don't retry close in case of EINTR!
   // See http://linux.derkeiler.com/Mailing-Lists/Kernel/2005-09/3000.html
   if (fd_ != -1 && ::FMT_POSIX(close(fd_)) != 0)
     fmt::ReportSystemError(errno, "cannot close file");
@@ -158,7 +158,7 @@ void File::pipe(File &read_end, File &write_end) {
 }
 
 BufferedFile File::fdopen(const char *mode) {
-  BufferedFile f(::fdopen(fd_, mode));
+  BufferedFile f(::FMT_POSIX(fdopen(fd_, mode)));
   fd_ = -1;
   return f;
 }
@@ -222,3 +222,9 @@ std::string OutputRedirect::RestoreAndRead() {
 }
 
 #endif  // FMT_USE_FILE_DESCRIPTORS
+
+std::string FormatSystemErrorMessage(int error_code, fmt::StringRef message) {
+  fmt::Writer out;
+  fmt::internal::FormatSystemErrorMessage(out, error_code, message);
+  return str(out);
+}
diff --git a/test/gtest-extra.h b/test/gtest-extra.h
index ee9512f6..05818d05 100644
--- a/test/gtest-extra.h
+++ b/test/gtest-extra.h
@@ -81,6 +81,12 @@
   FMT_TEST_THROW_(statement, expected_exception, \
       expected_message, GTEST_NONFATAL_FAILURE_)
 
+std::string FormatSystemErrorMessage(int error_code, fmt::StringRef message);
+
+#define EXPECT_SYSTEM_ERROR(statement, error_code, message) \
+  EXPECT_THROW_MSG(statement, fmt::SystemError, \
+      FormatSystemErrorMessage(error_code, message))
+
 #ifndef FMT_USE_FILE_DESCRIPTORS
 # define FMT_USE_FILE_DESCRIPTORS 0
 #endif