diff --git a/base/file.cpp b/base/file.cpp
index 3834ed4..e4407d0 100644
--- a/base/file.cpp
+++ b/base/file.cpp
@@ -19,6 +19,8 @@
 #include <errno.h>
 #include <fcntl.h>
 #include <libgen.h>
+#include <stdio.h>
+#include <stdlib.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <unistd.h>
@@ -37,10 +39,105 @@
 #include <mach-o/dyld.h>
 #endif
 #if defined(_WIN32)
+#include <direct.h>
 #include <windows.h>
 #define O_NOFOLLOW 0
+#define OS_PATH_SEPARATOR '\\'
+#else
+#define OS_PATH_SEPARATOR '/'
 #endif
 
+#ifdef _WIN32
+int mkstemp(char* template_name) {
+  if (_mktemp(template_name) == nullptr) {
+    return -1;
+  }
+  // Use open() to match the close() that TemporaryFile's destructor does.
+  // Use O_BINARY to match base file APIs.
+  return open(template_name, O_CREAT | O_EXCL | O_RDWR | O_BINARY, S_IRUSR | S_IWUSR);
+}
+
+char* mkdtemp(char* template_name) {
+  if (_mktemp(template_name) == nullptr) {
+    return nullptr;
+  }
+  if (_mkdir(template_name) == -1) {
+    return nullptr;
+  }
+  return template_name;
+}
+#endif
+
+namespace {
+
+std::string GetSystemTempDir() {
+#if defined(__ANDROID__)
+  const char* tmpdir = "/data/local/tmp";
+  if (access(tmpdir, R_OK | W_OK | X_OK) == 0) {
+    return tmpdir;
+  }
+  // Tests running in app context can't access /data/local/tmp,
+  // so try current directory if /data/local/tmp is not accessible.
+  return ".";
+#elif defined(_WIN32)
+  char tmp_dir[MAX_PATH];
+  DWORD result = GetTempPathA(sizeof(tmp_dir), tmp_dir);
+  CHECK_NE(result, 0ul) << "GetTempPathA failed, error: " << GetLastError();
+  CHECK_LT(result, sizeof(tmp_dir)) << "path truncated to: " << result;
+
+  // GetTempPath() returns a path with a trailing slash, but init()
+  // does not expect that, so remove it.
+  CHECK_EQ(tmp_dir[result - 1], '\\');
+  tmp_dir[result - 1] = '\0';
+  return tmp_dir;
+#else
+  return "/tmp";
+#endif
+}
+
+}  // namespace
+
+TemporaryFile::TemporaryFile() {
+  init(GetSystemTempDir());
+}
+
+TemporaryFile::TemporaryFile(const std::string& tmp_dir) {
+  init(tmp_dir);
+}
+
+TemporaryFile::~TemporaryFile() {
+  if (fd != -1) {
+    close(fd);
+  }
+  if (remove_file_) {
+    unlink(path);
+  }
+}
+
+int TemporaryFile::release() {
+  int result = fd;
+  fd = -1;
+  return result;
+}
+
+void TemporaryFile::init(const std::string& tmp_dir) {
+  snprintf(path, sizeof(path), "%s%cTemporaryFile-XXXXXX", tmp_dir.c_str(), OS_PATH_SEPARATOR);
+  fd = mkstemp(path);
+}
+
+TemporaryDir::TemporaryDir() {
+  init(GetSystemTempDir());
+}
+
+TemporaryDir::~TemporaryDir() {
+  rmdir(path);
+}
+
+bool TemporaryDir::init(const std::string& tmp_dir) {
+  snprintf(path, sizeof(path), "%s%cTemporaryDir-XXXXXX", tmp_dir.c_str(), OS_PATH_SEPARATOR);
+  return (mkdtemp(path) != nullptr);
+}
+
 namespace android {
 namespace base {
 
diff --git a/base/include/android-base/file.h b/base/include/android-base/file.h
index 86d537d..80d7134 100644
--- a/base/include/android-base/file.h
+++ b/base/include/android-base/file.h
@@ -18,8 +18,10 @@
 
 #include <sys/stat.h>
 #include <sys/types.h>
+
 #include <string>
 
+#include <android-base/macros.h>
 #include "android-base/off64_t.h"
 
 #if !defined(_WIN32) && !defined(O_BINARY)
@@ -32,6 +34,42 @@
 #define O_CLOEXEC O_NOINHERIT
 #endif
 
+class TemporaryFile {
+ public:
+  TemporaryFile();
+  explicit TemporaryFile(const std::string& tmp_dir);
+  ~TemporaryFile();
+
+  // Release the ownership of fd, caller is reponsible for closing the
+  // fd or stream properly.
+  int release();
+  // Don't remove the temporary file in the destructor.
+  void DoNotRemove() { remove_file_ = false; }
+
+  int fd;
+  char path[1024];
+
+ private:
+  void init(const std::string& tmp_dir);
+
+  bool remove_file_ = true;
+
+  DISALLOW_COPY_AND_ASSIGN(TemporaryFile);
+};
+
+class TemporaryDir {
+ public:
+  TemporaryDir();
+  ~TemporaryDir();
+
+  char path[1024];
+
+ private:
+  bool init(const std::string& tmp_dir);
+
+  DISALLOW_COPY_AND_ASSIGN(TemporaryDir);
+};
+
 namespace android {
 namespace base {
 
diff --git a/base/include/android-base/test_utils.h b/base/include/android-base/test_utils.h
index 2abe68e..b20f278 100644
--- a/base/include/android-base/test_utils.h
+++ b/base/include/android-base/test_utils.h
@@ -19,44 +19,9 @@
 #include <regex>
 #include <string>
 
+#include <android-base/file.h>
 #include <android-base/macros.h>
 
-class TemporaryFile {
- public:
-  TemporaryFile();
-  explicit TemporaryFile(const std::string& tmp_dir);
-  ~TemporaryFile();
-
-  // Release the ownership of fd, caller is reponsible for closing the
-  // fd or stream properly.
-  int release();
-  // Don't remove the temporary file in the destructor.
-  void DoNotRemove() { remove_file_ = false; }
-
-  int fd;
-  char path[1024];
-
- private:
-  void init(const std::string& tmp_dir);
-
-  bool remove_file_ = true;
-
-  DISALLOW_COPY_AND_ASSIGN(TemporaryFile);
-};
-
-class TemporaryDir {
- public:
-  TemporaryDir();
-  ~TemporaryDir();
-
-  char path[1024];
-
- private:
-  bool init(const std::string& tmp_dir);
-
-  DISALLOW_COPY_AND_ASSIGN(TemporaryDir);
-};
-
 class CapturedStdFd {
  public:
   CapturedStdFd(int std_fd);
diff --git a/base/test_utils.cpp b/base/test_utils.cpp
index 4d9466b..36b4cdf 100644
--- a/base/test_utils.cpp
+++ b/base/test_utils.cpp
@@ -22,109 +22,11 @@
 #include <sys/stat.h>
 #include <unistd.h>
 
-#if defined(_WIN32)
-#include <windows.h>
-#include <direct.h>
-#define OS_PATH_SEPARATOR '\\'
-#else
-#define OS_PATH_SEPARATOR '/'
-#endif
-
 #include <string>
 
 #include <android-base/file.h>
 #include <android-base/logging.h>
 
-#ifdef _WIN32
-int mkstemp(char* template_name) {
-  if (_mktemp(template_name) == nullptr) {
-    return -1;
-  }
-  // Use open() to match the close() that TemporaryFile's destructor does.
-  // Use O_BINARY to match base file APIs.
-  return open(template_name, O_CREAT | O_EXCL | O_RDWR | O_BINARY,
-              S_IRUSR | S_IWUSR);
-}
-
-char* mkdtemp(char* template_name) {
-  if (_mktemp(template_name) == nullptr) {
-    return nullptr;
-  }
-  if (_mkdir(template_name) == -1) {
-    return nullptr;
-  }
-  return template_name;
-}
-#endif
-
-static std::string GetSystemTempDir() {
-#if defined(__ANDROID__)
-  const char* tmpdir = "/data/local/tmp";
-  if (access(tmpdir, R_OK | W_OK | X_OK) == 0) {
-    return tmpdir;
-  }
-  // Tests running in app context can't access /data/local/tmp,
-  // so try current directory if /data/local/tmp is not accessible.
-  return ".";
-#elif defined(_WIN32)
-  char tmp_dir[MAX_PATH];
-  DWORD result = GetTempPathA(sizeof(tmp_dir), tmp_dir);
-  CHECK_NE(result, 0ul) << "GetTempPathA failed, error: " << GetLastError();
-  CHECK_LT(result, sizeof(tmp_dir)) << "path truncated to: " << result;
-
-  // GetTempPath() returns a path with a trailing slash, but init()
-  // does not expect that, so remove it.
-  CHECK_EQ(tmp_dir[result - 1], '\\');
-  tmp_dir[result - 1] = '\0';
-  return tmp_dir;
-#else
-  return "/tmp";
-#endif
-}
-
-TemporaryFile::TemporaryFile() {
-  init(GetSystemTempDir());
-}
-
-TemporaryFile::TemporaryFile(const std::string& tmp_dir) {
-  init(tmp_dir);
-}
-
-TemporaryFile::~TemporaryFile() {
-  if (fd != -1) {
-    close(fd);
-  }
-  if (remove_file_) {
-    unlink(path);
-  }
-}
-
-int TemporaryFile::release() {
-  int result = fd;
-  fd = -1;
-  return result;
-}
-
-void TemporaryFile::init(const std::string& tmp_dir) {
-  snprintf(path, sizeof(path), "%s%cTemporaryFile-XXXXXX", tmp_dir.c_str(),
-           OS_PATH_SEPARATOR);
-  fd = mkstemp(path);
-}
-
-TemporaryDir::TemporaryDir() {
-  init(GetSystemTempDir());
-}
-
-TemporaryDir::~TemporaryDir() {
-  rmdir(path);
-}
-
-bool TemporaryDir::init(const std::string& tmp_dir) {
-  snprintf(path, sizeof(path), "%s%cTemporaryDir-XXXXXX", tmp_dir.c_str(),
-           OS_PATH_SEPARATOR);
-  return (mkdtemp(path) != nullptr);
-}
-
 CapturedStdFd::CapturedStdFd(int std_fd) : std_fd_(std_fd), old_fd_(-1) {
   Start();
 }