diff --git a/src/test/cpp/blaze_util_test.cc b/src/test/cpp/blaze_util_test.cc
index 15963b6..03b43c0 100644
--- a/src/test/cpp/blaze_util_test.cc
+++ b/src/test/cpp/blaze_util_test.cc
@@ -211,20 +211,4 @@
                    "--flag"));
 }
 
-TEST_F(BlazeUtilTest, MakeAbsolute) {
-#if defined(WIN32)
-  EXPECT_EQ(MakeAbsolute("C:\\foo\\bar"), "C:\\foo\\bar");
-  EXPECT_EQ(MakeAbsolute("C:/foo/bar"), "C:\\foo\\bar");
-  EXPECT_EQ(MakeAbsolute("C:\\foo\\bar\\"), "C:\\foo\\bar\\");
-  EXPECT_EQ(MakeAbsolute("C:/foo/bar/"), "C:\\foo\\bar\\");
-  EXPECT_EQ(MakeAbsolute("foo"), blaze_util::GetCwd() + "\\foo");
-#else
-  EXPECT_EQ(MakeAbsolute("/foo/bar"), "/foo/bar");
-  EXPECT_EQ(MakeAbsolute("/foo/bar/"), "/foo/bar/");
-  EXPECT_EQ(MakeAbsolute("foo"), blaze_util::GetCwd() + "/foo");
-#endif
-  EXPECT_EQ(MakeAbsolute(std::string()), blaze_util::GetCwd());
-  EXPECT_EQ(MakeAbsolute("/dev/null"), "/dev/null");
-}
-
 }  // namespace blaze
diff --git a/src/test/cpp/blaze_util_windows_test.cc b/src/test/cpp/blaze_util_windows_test.cc
index 2ac5969..f577b48 100644
--- a/src/test/cpp/blaze_util_windows_test.cc
+++ b/src/test/cpp/blaze_util_windows_test.cc
@@ -155,27 +155,4 @@
   ASSERT_ENVVAR_UNSET(long_key.c_str());
 }
 
-TEST(BlazeUtilWindowsTest, ConvertPathTest) {
-  EXPECT_EQ("c:\\foo", ConvertPath("C:\\FOO"));
-  EXPECT_EQ("c:\\", ConvertPath("c:/"));
-  EXPECT_EQ("c:\\foo\\bar", ConvertPath("c:/../foo\\BAR\\.\\"));
-  EXPECT_EQ("nul", MakeAbsolute("NUL"));
-  EXPECT_EQ("nul", MakeAbsolute("nul"));
-  EXPECT_EQ("nul", MakeAbsolute("/dev/null"));
-}
-
-TEST(BlazeUtilWindowsTest, TestMakeAbsolute) {
-  EXPECT_EQ("c:\\foo\\bar", MakeAbsolute("C:\\foo\\BAR"));
-  EXPECT_EQ("c:\\foo\\bar", MakeAbsolute("C:/foo/bar"));
-  EXPECT_EQ("c:\\foo\\bar", MakeAbsolute("C:\\foo\\bar\\"));
-  EXPECT_EQ("c:\\foo\\bar", MakeAbsolute("C:/foo/bar/"));
-  EXPECT_EQ(blaze_util::AsLower(blaze_util::GetCwd()) + "\\foo",
-            MakeAbsolute("foo"));
-  EXPECT_EQ("nul", MakeAbsolute("NUL"));
-  EXPECT_EQ("nul", MakeAbsolute("Nul"));
-  EXPECT_EQ("nul", MakeAbsolute("nul"));
-  EXPECT_EQ(blaze_util::AsLower(blaze_util::GetCwd()), MakeAbsolute(""));
-  EXPECT_EQ("nul", MakeAbsolute("/dev/null"));
-}
-
 }  // namespace blaze
diff --git a/src/test/cpp/option_processor_test.cc b/src/test/cpp/option_processor_test.cc
index 01e2805..10e55cf 100644
--- a/src/test/cpp/option_processor_test.cc
+++ b/src/test/cpp/option_processor_test.cc
@@ -20,6 +20,7 @@
 #include "src/main/cpp/option_processor-internal.h"
 #include "src/main/cpp/util/file.h"
 #include "src/main/cpp/util/file_platform.h"
+#include "src/main/cpp/util/path.h"
 #include "src/main/cpp/workspace_layout.h"
 #include "googletest/include/gtest/gtest.h"
 
diff --git a/src/test/cpp/rc_file_test.cc b/src/test/cpp/rc_file_test.cc
index 5900db1..a534778 100644
--- a/src/test/cpp/rc_file_test.cc
+++ b/src/test/cpp/rc_file_test.cc
@@ -21,6 +21,7 @@
 #include "src/main/cpp/rc_file.h"
 #include "src/main/cpp/util/file.h"
 #include "src/main/cpp/util/file_platform.h"
+#include "src/main/cpp/util/path.h"
 #include "src/main/cpp/workspace_layout.h"
 #include "googlemock/include/gmock/gmock.h"
 #include "googletest/include/gtest/gtest.h"
diff --git a/src/test/cpp/rc_options_test.cc b/src/test/cpp/rc_options_test.cc
index 3a3ebf3..58251af 100644
--- a/src/test/cpp/rc_options_test.cc
+++ b/src/test/cpp/rc_options_test.cc
@@ -19,6 +19,7 @@
 #include "src/main/cpp/option_processor.h"
 #include "src/main/cpp/util/file.h"
 #include "src/main/cpp/util/file_platform.h"
+#include "src/main/cpp/util/path.h"
 #include "src/main/cpp/util/strings.h"
 #include "src/main/cpp/workspace_layout.h"
 #include "googletest/include/gtest/gtest.h"
diff --git a/src/test/cpp/util/BUILD b/src/test/cpp/util/BUILD
index 5dcb04a..455994f 100644
--- a/src/test/cpp/util/BUILD
+++ b/src/test/cpp/util/BUILD
@@ -31,7 +31,31 @@
     }),
     deps = [
         ":test_util",
-        "//src/main/cpp/util:file",
+        "//src/main/cpp/util:filesystem",
+        "@com_google_googletest//:gtest_main",
+    ] + select({
+        "//src/conditions:windows": [
+            ":windows_test_util",
+            "//src/main/native/windows:lib-file",
+        ],
+        "//conditions:default": [],
+    }),
+)
+
+cc_test(
+    name = "path_test",
+    size = "small",
+    srcs = select({
+        "//src/conditions:windows": [
+            "path_windows_test.cc",
+        ],
+        "//conditions:default": [
+            "path_posix_test.cc",
+        ],
+    }),
+    deps = [
+        ":test_util",
+        "//src/main/cpp/util:filesystem",
         "@com_google_googletest//:gtest_main",
     ] + select({
         "//src/conditions:windows": [
@@ -48,7 +72,7 @@
     deps = [
         "//src/main/cpp:blaze_util",
         "//src/main/cpp/util:bazel_log_handler",
-        "//src/main/cpp/util:file",
+        "//src/main/cpp/util:filesystem",
         "//src/main/cpp/util:logging",
         "@com_google_googletest//:gtest_main",
     ],
diff --git a/src/test/cpp/util/file_posix_test.cc b/src/test/cpp/util/file_posix_test.cc
index 688042c..75026af 100644
--- a/src/test/cpp/util/file_posix_test.cc
+++ b/src/test/cpp/util/file_posix_test.cc
@@ -19,6 +19,8 @@
 
 #include "src/main/cpp/util/file.h"
 #include "src/main/cpp/util/file_platform.h"
+#include "src/main/cpp/util/path.h"
+#include "src/main/cpp/util/path_platform.h"
 #include "src/test/cpp/util/test_util.h"
 #include "googletest/include/gtest/gtest.h"
 
@@ -46,73 +48,6 @@
   return close(fd) == 0;
 }
 
-TEST(FilePosixTest, TestDirname) {
-  // The Posix version of SplitPath (thus Dirname too, which is implemented on
-  // top of it) is not aware of Windows paths.
-  ASSERT_EQ("", Dirname(""));
-  ASSERT_EQ("/", Dirname("/"));
-  ASSERT_EQ("", Dirname("foo"));
-  ASSERT_EQ("/", Dirname("/foo"));
-  ASSERT_EQ("/foo", Dirname("/foo/"));
-  ASSERT_EQ("foo", Dirname("foo/bar"));
-  ASSERT_EQ("foo/bar", Dirname("foo/bar/baz"));
-  ASSERT_EQ("", Dirname("\\foo"));
-  ASSERT_EQ("", Dirname("\\foo\\"));
-  ASSERT_EQ("", Dirname("foo\\bar"));
-  ASSERT_EQ("", Dirname("foo\\bar\\baz"));
-  ASSERT_EQ("foo\\bar", Dirname("foo\\bar/baz\\qux"));
-  ASSERT_EQ("c:", Dirname("c:/"));
-  ASSERT_EQ("", Dirname("c:\\"));
-  ASSERT_EQ("c:", Dirname("c:/foo"));
-  ASSERT_EQ("", Dirname("c:\\foo"));
-  ASSERT_EQ("", Dirname("\\\\?\\c:\\"));
-  ASSERT_EQ("", Dirname("\\\\?\\c:\\foo"));
-}
-
-TEST(FilePosixTest, TestBasename) {
-  // The Posix version of SplitPath (thus Basename too, which is implemented on
-  // top of it) is not aware of Windows paths.
-  ASSERT_EQ("", Basename(""));
-  ASSERT_EQ("", Basename("/"));
-  ASSERT_EQ("foo", Basename("foo"));
-  ASSERT_EQ("foo", Basename("/foo"));
-  ASSERT_EQ("", Basename("/foo/"));
-  ASSERT_EQ("bar", Basename("foo/bar"));
-  ASSERT_EQ("baz", Basename("foo/bar/baz"));
-  ASSERT_EQ("\\foo", Basename("\\foo"));
-  ASSERT_EQ("\\foo\\", Basename("\\foo\\"));
-  ASSERT_EQ("foo\\bar", Basename("foo\\bar"));
-  ASSERT_EQ("foo\\bar\\baz", Basename("foo\\bar\\baz"));
-  ASSERT_EQ("baz\\qux", Basename("foo\\bar/baz\\qux"));
-  ASSERT_EQ("qux", Basename("qux"));
-  ASSERT_EQ("", Basename("c:/"));
-  ASSERT_EQ("c:\\", Basename("c:\\"));
-  ASSERT_EQ("foo", Basename("c:/foo"));
-  ASSERT_EQ("c:\\foo", Basename("c:\\foo"));
-  ASSERT_EQ("\\\\?\\c:\\", Basename("\\\\?\\c:\\"));
-  ASSERT_EQ("\\\\?\\c:\\foo", Basename("\\\\?\\c:\\foo"));
-}
-
-TEST(FilePosixTest, JoinPath) {
-  std::string path = JoinPath("", "");
-  ASSERT_EQ("", path);
-
-  path = JoinPath("a", "b");
-  ASSERT_EQ("a/b", path);
-
-  path = JoinPath("a/", "b");
-  ASSERT_EQ("a/b", path);
-
-  path = JoinPath("a", "/b");
-  ASSERT_EQ("a/b", path);
-
-  path = JoinPath("a/", "/b");
-  ASSERT_EQ("a/b", path);
-
-  path = JoinPath("/", "/");
-  ASSERT_EQ("/", path);
-}
-
 void MockDirectoryListingFunction(const string& path,
                                   DirectoryEntryConsumer* consume) {
   if (path == "root") {
@@ -272,24 +207,6 @@
   ASSERT_EQ(0, rmdir(dir.c_str()));
 }
 
-TEST(FilePosixTest, GetCwd) {
-  char cwdbuf[PATH_MAX];
-  ASSERT_EQ(cwdbuf, getcwd(cwdbuf, PATH_MAX));
-
-  // Assert that GetCwd() and getcwd() return the same value.
-  string cwd(cwdbuf);
-  ASSERT_EQ(cwd, blaze_util::GetCwd());
-
-  // Change to a different directory.
-  ASSERT_EQ(0, chdir("/usr"));
-
-  // Assert that GetCwd() returns the new CWD.
-  ASSERT_EQ(string("/usr"), blaze_util::GetCwd());
-
-  ASSERT_EQ(0, chdir(cwd.c_str()));
-  ASSERT_EQ(cwd, blaze_util::GetCwd());
-}
-
 TEST(FilePosixTest, ChangeDirectory) {
   // Retrieve the current working directory.
   char old_wd[PATH_MAX];
@@ -405,32 +322,4 @@
   rmdir(root.c_str());
 }
 
-TEST(FilePosixTest, IsAbsolute) {
-  ASSERT_FALSE(IsAbsolute(""));
-  ASSERT_TRUE(IsAbsolute("/"));
-  ASSERT_TRUE(IsAbsolute("/foo"));
-  ASSERT_FALSE(IsAbsolute("\\"));
-  ASSERT_FALSE(IsAbsolute("\\foo"));
-  ASSERT_FALSE(IsAbsolute("c:"));
-  ASSERT_FALSE(IsAbsolute("c:/"));
-  ASSERT_FALSE(IsAbsolute("c:\\"));
-  ASSERT_FALSE(IsAbsolute("c:\\foo"));
-  ASSERT_FALSE(IsAbsolute("\\\\?\\c:\\"));
-  ASSERT_FALSE(IsAbsolute("\\\\?\\c:\\foo"));
-}
-
-TEST(FilePosixTest, IsRootDirectory) {
-  ASSERT_FALSE(IsRootDirectory(""));
-  ASSERT_TRUE(IsRootDirectory("/"));
-  ASSERT_FALSE(IsRootDirectory("/foo"));
-  ASSERT_FALSE(IsRootDirectory("\\"));
-  ASSERT_FALSE(IsRootDirectory("\\foo"));
-  ASSERT_FALSE(IsRootDirectory("c:"));
-  ASSERT_FALSE(IsRootDirectory("c:/"));
-  ASSERT_FALSE(IsRootDirectory("c:\\"));
-  ASSERT_FALSE(IsRootDirectory("c:\\foo"));
-  ASSERT_FALSE(IsRootDirectory("\\\\?\\c:\\"));
-  ASSERT_FALSE(IsRootDirectory("\\\\?\\c:\\foo"));
-}
-
 }  // namespace blaze_util
diff --git a/src/test/cpp/util/file_test.cc b/src/test/cpp/util/file_test.cc
index c05b3b9..5f6f6ea 100644
--- a/src/test/cpp/util/file_test.cc
+++ b/src/test/cpp/util/file_test.cc
@@ -21,6 +21,8 @@
 #include <vector>
 
 #include "src/main/cpp/util/file.h"
+#include "src/main/cpp/util/path.h"
+#include "src/main/cpp/util/path_platform.h"
 #include "src/test/cpp/util/test_util.h"
 #include "googletest/include/gtest/gtest.h"
 
diff --git a/src/test/cpp/util/file_windows_test.cc b/src/test/cpp/util/file_windows_test.cc
index 87987b4..1844736 100644
--- a/src/test/cpp/util/file_windows_test.cc
+++ b/src/test/cpp/util/file_windows_test.cc
@@ -22,6 +22,8 @@
 #include "gtest/gtest.h"
 #include "src/main/cpp/util/file.h"
 #include "src/main/cpp/util/file_platform.h"
+#include "src/main/cpp/util/path.h"
+#include "src/main/cpp/util/path_platform.h"
 #include "src/main/cpp/util/strings.h"
 #include "src/main/native/windows/file.h"
 #include "src/main/native/windows/util.h"
@@ -40,7 +42,6 @@
 using std::wstring;
 
 // Methods defined in file_windows.cc that are only visible for testing.
-bool AsWindowsPath(const string& path, wstring* result, string* error);
 string NormalizeWindowsPath(string path);
 
 class FileWindowsTest : public ::testing::Test {
@@ -90,223 +91,6 @@
   AssertTearDown(L"test.teardown.b", L"test.teardown.a");
 }
 
-TEST_F(FileWindowsTest, TestNormalizeWindowsPath) {
-  ASSERT_EQ(string(""), NormalizeWindowsPath(""));
-  ASSERT_EQ(string(""), NormalizeWindowsPath("."));
-  ASSERT_EQ(string("foo"), NormalizeWindowsPath("foo"));
-  ASSERT_EQ(string("foo"), NormalizeWindowsPath("foo/"));
-  ASSERT_EQ(string("foo\\bar"), NormalizeWindowsPath("foo//bar"));
-  ASSERT_EQ(string("foo\\bar"), NormalizeWindowsPath("../..//foo/./bar"));
-  ASSERT_EQ(string("foo\\bar"), NormalizeWindowsPath("../foo/baz/../bar"));
-  ASSERT_EQ(string("c:\\"), NormalizeWindowsPath("c:"));
-  ASSERT_EQ(string("c:\\"), NormalizeWindowsPath("c:/"));
-  ASSERT_EQ(string("c:\\"), NormalizeWindowsPath("c:\\"));
-  ASSERT_EQ(string("c:\\foo\\bar"), NormalizeWindowsPath("c:\\..//foo/./bar/"));
-}
-
-TEST_F(FileWindowsTest, TestDirname) {
-  ASSERT_EQ("", Dirname(""));
-  ASSERT_EQ("/", Dirname("/"));
-  ASSERT_EQ("", Dirname("foo"));
-  ASSERT_EQ("/", Dirname("/foo"));
-  ASSERT_EQ("/foo", Dirname("/foo/"));
-  ASSERT_EQ("foo", Dirname("foo/bar"));
-  ASSERT_EQ("foo/bar", Dirname("foo/bar/baz"));
-  ASSERT_EQ("\\", Dirname("\\foo"));
-  ASSERT_EQ("\\foo", Dirname("\\foo\\"));
-  ASSERT_EQ("foo", Dirname("foo\\bar"));
-  ASSERT_EQ("foo\\bar", Dirname("foo\\bar\\baz"));
-  ASSERT_EQ("foo\\bar/baz", Dirname("foo\\bar/baz\\qux"));
-  ASSERT_EQ("c:/", Dirname("c:/"));
-  ASSERT_EQ("c:\\", Dirname("c:\\"));
-  ASSERT_EQ("c:/", Dirname("c:/foo"));
-  ASSERT_EQ("c:\\", Dirname("c:\\foo"));
-  ASSERT_EQ("\\\\?\\c:\\", Dirname("\\\\?\\c:\\"));
-  ASSERT_EQ("\\\\?\\c:\\", Dirname("\\\\?\\c:\\foo"));
-}
-
-TEST_F(FileWindowsTest, TestBasename) {
-  ASSERT_EQ("", Basename(""));
-  ASSERT_EQ("", Basename("/"));
-  ASSERT_EQ("foo", Basename("foo"));
-  ASSERT_EQ("foo", Basename("/foo"));
-  ASSERT_EQ("", Basename("/foo/"));
-  ASSERT_EQ("bar", Basename("foo/bar"));
-  ASSERT_EQ("baz", Basename("foo/bar/baz"));
-  ASSERT_EQ("foo", Basename("\\foo"));
-  ASSERT_EQ("", Basename("\\foo\\"));
-  ASSERT_EQ("bar", Basename("foo\\bar"));
-  ASSERT_EQ("baz", Basename("foo\\bar\\baz"));
-  ASSERT_EQ("qux", Basename("foo\\bar/baz\\qux"));
-  ASSERT_EQ("", Basename("c:/"));
-  ASSERT_EQ("", Basename("c:\\"));
-  ASSERT_EQ("foo", Basename("c:/foo"));
-  ASSERT_EQ("foo", Basename("c:\\foo"));
-  ASSERT_EQ("", Basename("\\\\?\\c:\\"));
-  ASSERT_EQ("foo", Basename("\\\\?\\c:\\foo"));
-}
-
-TEST_F(FileWindowsTest, TestIsAbsolute) {
-  ASSERT_FALSE(IsAbsolute(""));
-  ASSERT_TRUE(IsAbsolute("/"));
-  ASSERT_TRUE(IsAbsolute("/foo"));
-  ASSERT_TRUE(IsAbsolute("\\"));
-  ASSERT_TRUE(IsAbsolute("\\foo"));
-  ASSERT_FALSE(IsAbsolute("c:"));
-  ASSERT_TRUE(IsAbsolute("c:/"));
-  ASSERT_TRUE(IsAbsolute("c:\\"));
-  ASSERT_TRUE(IsAbsolute("c:\\foo"));
-  ASSERT_TRUE(IsAbsolute("\\\\?\\c:\\"));
-  ASSERT_TRUE(IsAbsolute("\\\\?\\c:\\foo"));
-}
-
-TEST_F(FileWindowsTest, TestIsRootDirectory) {
-  ASSERT_FALSE(IsRootDirectory(""));
-  ASSERT_TRUE(IsRootDirectory("/"));
-  ASSERT_FALSE(IsRootDirectory("/foo"));
-  ASSERT_TRUE(IsRootDirectory("\\"));
-  ASSERT_FALSE(IsRootDirectory("\\foo"));
-  ASSERT_FALSE(IsRootDirectory("c:"));
-  ASSERT_TRUE(IsRootDirectory("c:/"));
-  ASSERT_TRUE(IsRootDirectory("c:\\"));
-  ASSERT_FALSE(IsRootDirectory("c:\\foo"));
-  ASSERT_TRUE(IsRootDirectory("\\\\?\\c:\\"));
-  ASSERT_FALSE(IsRootDirectory("\\\\?\\c:\\foo"));
-}
-
-TEST_F(FileWindowsTest, TestAsWindowsPath) {
-  SetEnvironmentVariableA("BAZEL_SH", "c:\\some\\long/path\\bin\\bash.exe");
-  wstring actual;
-
-  // Null and empty input produces empty result.
-  ASSERT_TRUE(AsWindowsPath("", &actual, nullptr));
-  ASSERT_EQ(wstring(L""), actual);
-
-  // If the path has a "\\?\" prefix, AsWindowsPath assumes it's a correct
-  // Windows path. If it's not, the Windows API function that we pass the path
-  // to will fail anyway.
-  ASSERT_TRUE(AsWindowsPath("\\\\?\\anything/..", &actual, nullptr));
-  ASSERT_EQ(wstring(L"\\\\?\\anything/.."), actual);
-
-  // Trailing slash or backslash is removed.
-  ASSERT_TRUE(AsWindowsPath("foo/", &actual, nullptr));
-  ASSERT_EQ(wstring(L"foo"), actual);
-  ASSERT_TRUE(AsWindowsPath("foo\\", &actual, nullptr));
-  ASSERT_EQ(wstring(L"foo"), actual);
-
-  // Slashes are converted to backslash.
-  ASSERT_TRUE(AsWindowsPath("foo/bar", &actual, nullptr));
-  ASSERT_EQ(wstring(L"foo\\bar"), actual);
-  ASSERT_TRUE(AsWindowsPath("c:/", &actual, nullptr));
-  ASSERT_EQ(wstring(L"c:\\"), actual);
-  ASSERT_TRUE(AsWindowsPath("c:\\", &actual, nullptr));
-  ASSERT_EQ(wstring(L"c:\\"), actual);
-
-  // Invalid paths
-  string error;
-  ASSERT_FALSE(AsWindowsPath("c:", &actual, &error));
-  EXPECT_TRUE(error.find("working-directory relative paths") != string::npos);
-  ASSERT_FALSE(AsWindowsPath("c:foo", &actual, &error));
-  EXPECT_TRUE(error.find("working-directory relative paths") != string::npos);
-  ASSERT_FALSE(AsWindowsPath("\\\\foo", &actual, &error));
-  EXPECT_TRUE(error.find("network paths") != string::npos);
-
-  // /dev/null and NUL produce NUL.
-  ASSERT_TRUE(AsWindowsPath("/dev/null", &actual, nullptr));
-  ASSERT_EQ(wstring(L"NUL"), actual);
-  ASSERT_TRUE(AsWindowsPath("Nul", &actual, nullptr));
-  ASSERT_EQ(wstring(L"NUL"), actual);
-
-  // MSYS path with drive letter.
-  ASSERT_FALSE(AsWindowsPath("/c", &actual, &error));
-  EXPECT_TRUE(error.find("Unix-style") != string::npos);
-  ASSERT_FALSE(AsWindowsPath("/c/", &actual, &error));
-  EXPECT_TRUE(error.find("Unix-style") != string::npos);
-
-  // Absolute-on-current-drive path gets a drive letter.
-  ASSERT_TRUE(AsWindowsPath("\\foo", &actual, nullptr));
-  ASSERT_EQ(wstring(1, GetCwd()[0]) + L":\\foo", actual);
-
-  // Even for long paths, AsWindowsPath doesn't add a "\\?\" prefix (it's the
-  // caller's duty to do so).
-  wstring wlongpath(L"dummy_long_path\\");
-  string longpath("dummy_long_path/");
-  while (longpath.size() <= MAX_PATH) {
-    wlongpath += wlongpath;
-    longpath += longpath;
-  }
-  wlongpath.pop_back();  // remove trailing "\"
-  ASSERT_TRUE(AsWindowsPath(longpath, &actual, nullptr));
-  ASSERT_EQ(wlongpath, actual);
-}
-
-TEST_F(FileWindowsTest, TestAsAbsoluteWindowsPath) {
-  SetEnvironmentVariableA("BAZEL_SH", "c:\\some\\long/path\\bin\\bash.exe");
-  wstring actual;
-
-  ASSERT_TRUE(AsAbsoluteWindowsPath("c:/", &actual, nullptr));
-  ASSERT_EQ(L"\\\\?\\c:\\", actual);
-
-  ASSERT_TRUE(AsAbsoluteWindowsPath("c:/..\\non-existent//", &actual, nullptr));
-  ASSERT_EQ(L"\\\\?\\c:\\non-existent", actual);
-
-  WCHAR cwd[MAX_PATH];
-  wstring cwdw(CstringToWstring(GetCwd().c_str()).get());
-  wstring expected =
-      wstring(L"\\\\?\\") + cwdw +
-      ((cwdw.back() == L'\\') ? L"non-existent" : L"\\non-existent");
-  ASSERT_TRUE(AsAbsoluteWindowsPath("non-existent", &actual, nullptr));
-  ASSERT_EQ(actual, expected);
-}
-
-TEST_F(FileWindowsTest, TestAsShortWindowsPath) {
-  string actual;
-  ASSERT_TRUE(AsShortWindowsPath("/dev/null", &actual, nullptr));
-  ASSERT_EQ(string("NUL"), actual);
-
-  ASSERT_TRUE(AsShortWindowsPath("nul", &actual, nullptr));
-  ASSERT_EQ(string("NUL"), actual);
-
-  ASSERT_TRUE(AsShortWindowsPath("C://", &actual, nullptr));
-  ASSERT_EQ(string("c:\\"), actual);
-
-  string error;
-  ASSERT_FALSE(AsShortWindowsPath("/C//", &actual, &error));
-  EXPECT_TRUE(error.find("Unix-style") != string::npos);
-
-  // The A drive usually doesn't exist but AsShortWindowsPath should still work.
-  // Here we even have multiple trailing slashes, that should be handled too.
-  ASSERT_TRUE(AsShortWindowsPath("A://", &actual, nullptr));
-  ASSERT_EQ(string("a:\\"), actual);
-
-  // Assert that we can shorten the TEST_TMPDIR.
-  string tmpdir;
-  GET_TEST_TMPDIR(tmpdir);
-  string short_tmpdir;
-  ASSERT_TRUE(AsShortWindowsPath(tmpdir, &short_tmpdir, nullptr));
-  ASSERT_LT(0, short_tmpdir.size());
-  ASSERT_TRUE(PathExists(short_tmpdir));
-
-  // Assert that a trailing "/" doesn't change the shortening logic and it will
-  // be stripped from the result.
-  ASSERT_TRUE(AsShortWindowsPath(tmpdir + "/", &actual, nullptr));
-  ASSERT_EQ(actual, short_tmpdir);
-  ASSERT_NE(actual.back(), '/');
-  ASSERT_NE(actual.back(), '\\');
-
-  // Assert shortening another long path, and that the result is lowercased.
-  string dirname(JoinPath(short_tmpdir, "LONGpathNAME"));
-  ASSERT_EQ(0, mkdir(dirname.c_str()));
-  ASSERT_TRUE(PathExists(dirname));
-  ASSERT_TRUE(AsShortWindowsPath(dirname, &actual, nullptr));
-  ASSERT_EQ(short_tmpdir + "\\longpa~1", actual);
-
-  // Assert shortening non-existent paths.
-  ASSERT_TRUE(AsShortWindowsPath(JoinPath(tmpdir, "NonExistent/FOO"), &actual,
-                                 nullptr));
-  ASSERT_EQ(short_tmpdir + "\\nonexistent\\foo", actual);
-}
-
 TEST_F(FileWindowsTest, TestMsysRootRetrieval) {
   wstring actual;
 
@@ -513,18 +297,4 @@
   ASSERT_EQ(dircanon, symcanon);
 }
 
-TEST(FileTest, IsWindowsDevNullTest) {
-  ASSERT_TRUE(IsDevNull("nul"));
-  ASSERT_TRUE(IsDevNull("NUL"));
-  ASSERT_TRUE(IsDevNull("nuL"));
-  ASSERT_TRUE(IsDevNull("/dev/null"));
-  ASSERT_FALSE(IsDevNull("/Dev/Null"));
-  ASSERT_FALSE(IsDevNull("dev/null"));
-  ASSERT_FALSE(IsDevNull("/dev/nul"));
-  ASSERT_FALSE(IsDevNull("/dev/nulll"));
-  ASSERT_FALSE(IsDevNull("nu"));
-  ASSERT_FALSE(IsDevNull(NULL));
-  ASSERT_FALSE(IsDevNull(""));
-}
-
 }  // namespace blaze_util
diff --git a/src/test/cpp/util/logging_test.cc b/src/test/cpp/util/logging_test.cc
index f3ced04..d48c177 100644
--- a/src/test/cpp/util/logging_test.cc
+++ b/src/test/cpp/util/logging_test.cc
@@ -20,6 +20,7 @@
 #include "src/main/cpp/util/bazel_log_handler.h"
 #include "src/main/cpp/util/file.h"
 #include "src/main/cpp/util/logging.h"
+#include "src/main/cpp/util/path.h"
 #include "googlemock/include/gmock/gmock.h"
 #include "googletest/include/gtest/gtest.h"
 
diff --git a/src/test/cpp/util/path_posix_test.cc b/src/test/cpp/util/path_posix_test.cc
new file mode 100644
index 0000000..7d0e497
--- /dev/null
+++ b/src/test/cpp/util/path_posix_test.cc
@@ -0,0 +1,162 @@
+// Copyright 2018 The Bazel Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+#include <fcntl.h>
+#include <limits.h>
+#include <unistd.h>
+
+#include <algorithm>
+
+#include "src/main/cpp/util/file_platform.h"
+#include "src/main/cpp/util/path.h"
+#include "src/main/cpp/util/path_platform.h"
+#include "src/test/cpp/util/test_util.h"
+#include "googletest/include/gtest/gtest.h"
+
+namespace blaze_util {
+
+using std::pair;
+using std::string;
+using std::vector;
+
+TEST(PathPosixTest, TestDirname) {
+  // The Posix version of SplitPath (thus Dirname too, which is implemented on
+  // top of it) is not aware of Windows paths.
+  ASSERT_EQ("", Dirname(""));
+  ASSERT_EQ("/", Dirname("/"));
+  ASSERT_EQ("", Dirname("foo"));
+  ASSERT_EQ("/", Dirname("/foo"));
+  ASSERT_EQ("/foo", Dirname("/foo/"));
+  ASSERT_EQ("foo", Dirname("foo/bar"));
+  ASSERT_EQ("foo/bar", Dirname("foo/bar/baz"));
+  ASSERT_EQ("", Dirname("\\foo"));
+  ASSERT_EQ("", Dirname("\\foo\\"));
+  ASSERT_EQ("", Dirname("foo\\bar"));
+  ASSERT_EQ("", Dirname("foo\\bar\\baz"));
+  ASSERT_EQ("foo\\bar", Dirname("foo\\bar/baz\\qux"));
+  ASSERT_EQ("c:", Dirname("c:/"));
+  ASSERT_EQ("", Dirname("c:\\"));
+  ASSERT_EQ("c:", Dirname("c:/foo"));
+  ASSERT_EQ("", Dirname("c:\\foo"));
+  ASSERT_EQ("", Dirname("\\\\?\\c:\\"));
+  ASSERT_EQ("", Dirname("\\\\?\\c:\\foo"));
+}
+
+TEST(PathPosixTest, TestBasename) {
+  // The Posix version of SplitPath (thus Basename too, which is implemented on
+  // top of it) is not aware of Windows paths.
+  ASSERT_EQ("", Basename(""));
+  ASSERT_EQ("", Basename("/"));
+  ASSERT_EQ("foo", Basename("foo"));
+  ASSERT_EQ("foo", Basename("/foo"));
+  ASSERT_EQ("", Basename("/foo/"));
+  ASSERT_EQ("bar", Basename("foo/bar"));
+  ASSERT_EQ("baz", Basename("foo/bar/baz"));
+  ASSERT_EQ("\\foo", Basename("\\foo"));
+  ASSERT_EQ("\\foo\\", Basename("\\foo\\"));
+  ASSERT_EQ("foo\\bar", Basename("foo\\bar"));
+  ASSERT_EQ("foo\\bar\\baz", Basename("foo\\bar\\baz"));
+  ASSERT_EQ("baz\\qux", Basename("foo\\bar/baz\\qux"));
+  ASSERT_EQ("qux", Basename("qux"));
+  ASSERT_EQ("", Basename("c:/"));
+  ASSERT_EQ("c:\\", Basename("c:\\"));
+  ASSERT_EQ("foo", Basename("c:/foo"));
+  ASSERT_EQ("c:\\foo", Basename("c:\\foo"));
+  ASSERT_EQ("\\\\?\\c:\\", Basename("\\\\?\\c:\\"));
+  ASSERT_EQ("\\\\?\\c:\\foo", Basename("\\\\?\\c:\\foo"));
+}
+
+TEST(PathPosixTest, JoinPath) {
+  std::string path = JoinPath("", "");
+  ASSERT_EQ("", path);
+
+  path = JoinPath("a", "b");
+  ASSERT_EQ("a/b", path);
+
+  path = JoinPath("a/", "b");
+  ASSERT_EQ("a/b", path);
+
+  path = JoinPath("a", "/b");
+  ASSERT_EQ("a/b", path);
+
+  path = JoinPath("a/", "/b");
+  ASSERT_EQ("a/b", path);
+
+  path = JoinPath("/", "/");
+  ASSERT_EQ("/", path);
+}
+
+TEST(PathPosixTest, GetCwd) {
+  char cwdbuf[PATH_MAX];
+  ASSERT_EQ(cwdbuf, getcwd(cwdbuf, PATH_MAX));
+
+  // Assert that GetCwd() and getcwd() return the same value.
+  string cwd(cwdbuf);
+  ASSERT_EQ(cwd, blaze_util::GetCwd());
+
+  // Change to a different directory.
+  ASSERT_EQ(0, chdir("/usr"));
+
+  // Assert that GetCwd() returns the new CWD.
+  ASSERT_EQ(string("/usr"), blaze_util::GetCwd());
+
+  ASSERT_EQ(0, chdir(cwd.c_str()));
+  ASSERT_EQ(cwd, blaze_util::GetCwd());
+}
+
+TEST(PathPosixTest, IsAbsolute) {
+  ASSERT_FALSE(IsAbsolute(""));
+  ASSERT_TRUE(IsAbsolute("/"));
+  ASSERT_TRUE(IsAbsolute("/foo"));
+  ASSERT_FALSE(IsAbsolute("\\"));
+  ASSERT_FALSE(IsAbsolute("\\foo"));
+  ASSERT_FALSE(IsAbsolute("c:"));
+  ASSERT_FALSE(IsAbsolute("c:/"));
+  ASSERT_FALSE(IsAbsolute("c:\\"));
+  ASSERT_FALSE(IsAbsolute("c:\\foo"));
+  ASSERT_FALSE(IsAbsolute("\\\\?\\c:\\"));
+  ASSERT_FALSE(IsAbsolute("\\\\?\\c:\\foo"));
+}
+
+TEST(PathPosixTest, IsRootDirectory) {
+  ASSERT_FALSE(IsRootDirectory(""));
+  ASSERT_TRUE(IsRootDirectory("/"));
+  ASSERT_FALSE(IsRootDirectory("/foo"));
+  ASSERT_FALSE(IsRootDirectory("\\"));
+  ASSERT_FALSE(IsRootDirectory("\\foo"));
+  ASSERT_FALSE(IsRootDirectory("c:"));
+  ASSERT_FALSE(IsRootDirectory("c:/"));
+  ASSERT_FALSE(IsRootDirectory("c:\\"));
+  ASSERT_FALSE(IsRootDirectory("c:\\foo"));
+  ASSERT_FALSE(IsRootDirectory("\\\\?\\c:\\"));
+  ASSERT_FALSE(IsRootDirectory("\\\\?\\c:\\foo"));
+}
+
+TEST(PathPosixTest, IsDevNullTest) {
+  ASSERT_TRUE(IsDevNull("/dev/null"));
+  ASSERT_FALSE(IsDevNull("dev/null"));
+  ASSERT_FALSE(IsDevNull("/dev/nul"));
+  ASSERT_FALSE(IsDevNull("/dev/nulll"));
+  ASSERT_FALSE(IsDevNull(NULL));
+  ASSERT_FALSE(IsDevNull(""));
+}
+
+TEST(PathPosixTest, MakeAbsolute) {
+  EXPECT_EQ(MakeAbsolute("/foo/bar"), "/foo/bar");
+  EXPECT_EQ(MakeAbsolute("/foo/bar/"), "/foo/bar/");
+  EXPECT_EQ(MakeAbsolute("foo"), blaze_util::GetCwd() + "/foo");
+  EXPECT_EQ(MakeAbsolute(std::string()), blaze_util::GetCwd());
+  EXPECT_EQ(MakeAbsolute("/dev/null"), "/dev/null");
+}
+
+}  // namespace blaze_util
diff --git a/src/test/cpp/util/path_windows_test.cc b/src/test/cpp/util/path_windows_test.cc
new file mode 100644
index 0000000..789f67c
--- /dev/null
+++ b/src/test/cpp/util/path_windows_test.cc
@@ -0,0 +1,318 @@
+// Copyright 2016 The Bazel Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+#include <stdio.h>
+#include <string.h>
+#include <windows.h>
+
+#include <algorithm>
+#include <memory>
+#include <string>
+
+#include "gtest/gtest.h"
+#include "src/main/cpp/util/file_platform.h"
+#include "src/main/cpp/util/path.h"
+#include "src/main/cpp/util/path_platform.h"
+#include "src/main/cpp/util/strings.h"
+#include "src/main/native/windows/file.h"
+#include "src/main/native/windows/util.h"
+#include "src/test/cpp/util/test_util.h"
+#include "src/test/cpp/util/windows_test_util.h"
+
+#if !defined(COMPILER_MSVC) && !defined(__CYGWIN__)
+#error("This test should only be run on Windows")
+#endif  // !defined(COMPILER_MSVC) && !defined(__CYGWIN__)
+
+namespace blaze_util {
+
+using bazel::windows::CreateJunction;
+using std::string;
+using std::unique_ptr;
+using std::wstring;
+
+// Methods defined in path_windows.cc that are only visible for testing.
+string NormalizeWindowsPath(string path);
+
+TEST(PathWindowsTest, TestNormalizeWindowsPath) {
+  ASSERT_EQ(string(""), NormalizeWindowsPath(""));
+  ASSERT_EQ(string(""), NormalizeWindowsPath("."));
+  ASSERT_EQ(string("foo"), NormalizeWindowsPath("foo"));
+  ASSERT_EQ(string("foo"), NormalizeWindowsPath("foo/"));
+  ASSERT_EQ(string("foo\\bar"), NormalizeWindowsPath("foo//bar"));
+  ASSERT_EQ(string("foo\\bar"), NormalizeWindowsPath("../..//foo/./bar"));
+  ASSERT_EQ(string("foo\\bar"), NormalizeWindowsPath("../foo/baz/../bar"));
+  ASSERT_EQ(string("c:\\"), NormalizeWindowsPath("c:"));
+  ASSERT_EQ(string("c:\\"), NormalizeWindowsPath("c:/"));
+  ASSERT_EQ(string("c:\\"), NormalizeWindowsPath("c:\\"));
+  ASSERT_EQ(string("c:\\foo\\bar"), NormalizeWindowsPath("c:\\..//foo/./bar/"));
+}
+
+TEST(PathWindowsTest, TestDirname) {
+  ASSERT_EQ("", Dirname(""));
+  ASSERT_EQ("/", Dirname("/"));
+  ASSERT_EQ("", Dirname("foo"));
+  ASSERT_EQ("/", Dirname("/foo"));
+  ASSERT_EQ("/foo", Dirname("/foo/"));
+  ASSERT_EQ("foo", Dirname("foo/bar"));
+  ASSERT_EQ("foo/bar", Dirname("foo/bar/baz"));
+  ASSERT_EQ("\\", Dirname("\\foo"));
+  ASSERT_EQ("\\foo", Dirname("\\foo\\"));
+  ASSERT_EQ("foo", Dirname("foo\\bar"));
+  ASSERT_EQ("foo\\bar", Dirname("foo\\bar\\baz"));
+  ASSERT_EQ("foo\\bar/baz", Dirname("foo\\bar/baz\\qux"));
+  ASSERT_EQ("c:/", Dirname("c:/"));
+  ASSERT_EQ("c:\\", Dirname("c:\\"));
+  ASSERT_EQ("c:/", Dirname("c:/foo"));
+  ASSERT_EQ("c:\\", Dirname("c:\\foo"));
+  ASSERT_EQ("\\\\?\\c:\\", Dirname("\\\\?\\c:\\"));
+  ASSERT_EQ("\\\\?\\c:\\", Dirname("\\\\?\\c:\\foo"));
+}
+
+TEST(PathWindowsTest, TestBasename) {
+  ASSERT_EQ("", Basename(""));
+  ASSERT_EQ("", Basename("/"));
+  ASSERT_EQ("foo", Basename("foo"));
+  ASSERT_EQ("foo", Basename("/foo"));
+  ASSERT_EQ("", Basename("/foo/"));
+  ASSERT_EQ("bar", Basename("foo/bar"));
+  ASSERT_EQ("baz", Basename("foo/bar/baz"));
+  ASSERT_EQ("foo", Basename("\\foo"));
+  ASSERT_EQ("", Basename("\\foo\\"));
+  ASSERT_EQ("bar", Basename("foo\\bar"));
+  ASSERT_EQ("baz", Basename("foo\\bar\\baz"));
+  ASSERT_EQ("qux", Basename("foo\\bar/baz\\qux"));
+  ASSERT_EQ("", Basename("c:/"));
+  ASSERT_EQ("", Basename("c:\\"));
+  ASSERT_EQ("foo", Basename("c:/foo"));
+  ASSERT_EQ("foo", Basename("c:\\foo"));
+  ASSERT_EQ("", Basename("\\\\?\\c:\\"));
+  ASSERT_EQ("foo", Basename("\\\\?\\c:\\foo"));
+}
+
+TEST(PathWindowsTest, TestIsAbsolute) {
+  ASSERT_FALSE(IsAbsolute(""));
+  ASSERT_TRUE(IsAbsolute("/"));
+  ASSERT_TRUE(IsAbsolute("/foo"));
+  ASSERT_TRUE(IsAbsolute("\\"));
+  ASSERT_TRUE(IsAbsolute("\\foo"));
+  ASSERT_FALSE(IsAbsolute("c:"));
+  ASSERT_TRUE(IsAbsolute("c:/"));
+  ASSERT_TRUE(IsAbsolute("c:\\"));
+  ASSERT_TRUE(IsAbsolute("c:\\foo"));
+  ASSERT_TRUE(IsAbsolute("\\\\?\\c:\\"));
+  ASSERT_TRUE(IsAbsolute("\\\\?\\c:\\foo"));
+}
+
+TEST(PathWindowsTest, TestIsRootDirectory) {
+  ASSERT_FALSE(IsRootDirectory(""));
+  ASSERT_TRUE(IsRootDirectory("/"));
+  ASSERT_FALSE(IsRootDirectory("/foo"));
+  ASSERT_TRUE(IsRootDirectory("\\"));
+  ASSERT_FALSE(IsRootDirectory("\\foo"));
+  ASSERT_FALSE(IsRootDirectory("c:"));
+  ASSERT_TRUE(IsRootDirectory("c:/"));
+  ASSERT_TRUE(IsRootDirectory("c:\\"));
+  ASSERT_FALSE(IsRootDirectory("c:\\foo"));
+  ASSERT_TRUE(IsRootDirectory("\\\\?\\c:\\"));
+  ASSERT_FALSE(IsRootDirectory("\\\\?\\c:\\foo"));
+}
+
+TEST(PathWindowsTest, TestAsWindowsPath) {
+  SetEnvironmentVariableA("BAZEL_SH", "c:\\some\\long/path\\bin\\bash.exe");
+  wstring actual;
+
+  // Null and empty input produces empty result.
+  ASSERT_TRUE(AsWindowsPath("", &actual, nullptr));
+  ASSERT_EQ(wstring(L""), actual);
+
+  // If the path has a "\\?\" prefix, AsWindowsPath assumes it's a correct
+  // Windows path. If it's not, the Windows API function that we pass the path
+  // to will fail anyway.
+  ASSERT_TRUE(AsWindowsPath("\\\\?\\anything/..", &actual, nullptr));
+  ASSERT_EQ(wstring(L"\\\\?\\anything/.."), actual);
+
+  // Trailing slash or backslash is removed.
+  ASSERT_TRUE(AsWindowsPath("foo/", &actual, nullptr));
+  ASSERT_EQ(wstring(L"foo"), actual);
+  ASSERT_TRUE(AsWindowsPath("foo\\", &actual, nullptr));
+  ASSERT_EQ(wstring(L"foo"), actual);
+
+  // Slashes are converted to backslash.
+  ASSERT_TRUE(AsWindowsPath("foo/bar", &actual, nullptr));
+  ASSERT_EQ(wstring(L"foo\\bar"), actual);
+  ASSERT_TRUE(AsWindowsPath("c:/", &actual, nullptr));
+  ASSERT_EQ(wstring(L"c:\\"), actual);
+  ASSERT_TRUE(AsWindowsPath("c:\\", &actual, nullptr));
+  ASSERT_EQ(wstring(L"c:\\"), actual);
+
+  // Invalid paths
+  string error;
+  ASSERT_FALSE(AsWindowsPath("c:", &actual, &error));
+  EXPECT_TRUE(error.find("working-directory relative paths") != string::npos);
+  ASSERT_FALSE(AsWindowsPath("c:foo", &actual, &error));
+  EXPECT_TRUE(error.find("working-directory relative paths") != string::npos);
+  ASSERT_FALSE(AsWindowsPath("\\\\foo", &actual, &error));
+  EXPECT_TRUE(error.find("network paths") != string::npos);
+
+  // /dev/null and NUL produce NUL.
+  ASSERT_TRUE(AsWindowsPath("/dev/null", &actual, nullptr));
+  ASSERT_EQ(wstring(L"NUL"), actual);
+  ASSERT_TRUE(AsWindowsPath("Nul", &actual, nullptr));
+  ASSERT_EQ(wstring(L"NUL"), actual);
+
+  // MSYS path with drive letter.
+  ASSERT_FALSE(AsWindowsPath("/c", &actual, &error));
+  EXPECT_TRUE(error.find("Unix-style") != string::npos);
+  ASSERT_FALSE(AsWindowsPath("/c/", &actual, &error));
+  EXPECT_TRUE(error.find("Unix-style") != string::npos);
+
+  // Absolute-on-current-drive path gets a drive letter.
+  ASSERT_TRUE(AsWindowsPath("\\foo", &actual, nullptr));
+  ASSERT_EQ(wstring(1, GetCwd()[0]) + L":\\foo", actual);
+
+  // Even for long paths, AsWindowsPath doesn't add a "\\?\" prefix (it's the
+  // caller's duty to do so).
+  wstring wlongpath(L"dummy_long_path\\");
+  string longpath("dummy_long_path/");
+  while (longpath.size() <= MAX_PATH) {
+    wlongpath += wlongpath;
+    longpath += longpath;
+  }
+  wlongpath.pop_back();  // remove trailing "\"
+  ASSERT_TRUE(AsWindowsPath(longpath, &actual, nullptr));
+  ASSERT_EQ(wlongpath, actual);
+}
+
+TEST(PathWindowsTest, TestAsAbsoluteWindowsPath) {
+  SetEnvironmentVariableA("BAZEL_SH", "c:\\some\\long/path\\bin\\bash.exe");
+  wstring actual;
+
+  ASSERT_TRUE(AsAbsoluteWindowsPath("c:/", &actual, nullptr));
+  ASSERT_EQ(L"\\\\?\\c:\\", actual);
+
+  ASSERT_TRUE(AsAbsoluteWindowsPath("c:/..\\non-existent//", &actual, nullptr));
+  ASSERT_EQ(L"\\\\?\\c:\\non-existent", actual);
+
+  WCHAR cwd[MAX_PATH];
+  wstring cwdw(CstringToWstring(GetCwd().c_str()).get());
+  wstring expected =
+      wstring(L"\\\\?\\") + cwdw +
+      ((cwdw.back() == L'\\') ? L"non-existent" : L"\\non-existent");
+  ASSERT_TRUE(AsAbsoluteWindowsPath("non-existent", &actual, nullptr));
+  ASSERT_EQ(actual, expected);
+}
+
+TEST(PathWindowsTest, TestAsShortWindowsPath) {
+  string actual;
+  ASSERT_TRUE(AsShortWindowsPath("/dev/null", &actual, nullptr));
+  ASSERT_EQ(string("NUL"), actual);
+
+  ASSERT_TRUE(AsShortWindowsPath("nul", &actual, nullptr));
+  ASSERT_EQ(string("NUL"), actual);
+
+  ASSERT_TRUE(AsShortWindowsPath("C://", &actual, nullptr));
+  ASSERT_EQ(string("c:\\"), actual);
+
+  string error;
+  ASSERT_FALSE(AsShortWindowsPath("/C//", &actual, &error));
+  EXPECT_TRUE(error.find("Unix-style") != string::npos);
+
+  // The A drive usually doesn't exist but AsShortWindowsPath should still work.
+  // Here we even have multiple trailing slashes, that should be handled too.
+  ASSERT_TRUE(AsShortWindowsPath("A://", &actual, nullptr));
+  ASSERT_EQ(string("a:\\"), actual);
+
+  // Assert that we can shorten the TEST_TMPDIR.
+  char buf[MAX_PATH] = {0};
+  DWORD len = ::GetEnvironmentVariableA("TEST_TMPDIR", buf, MAX_PATH);
+  string tmpdir = buf;
+  ASSERT_GT(tmpdir.size(), 0);
+  string short_tmpdir;
+  ASSERT_TRUE(AsShortWindowsPath(tmpdir, &short_tmpdir, nullptr));
+  ASSERT_LT(0, short_tmpdir.size());
+  ASSERT_TRUE(PathExists(short_tmpdir));
+
+  // Assert that a trailing "/" doesn't change the shortening logic and it will
+  // be stripped from the result.
+  ASSERT_TRUE(AsShortWindowsPath(tmpdir + "/", &actual, nullptr));
+  ASSERT_EQ(actual, short_tmpdir);
+  ASSERT_NE(actual.back(), '/');
+  ASSERT_NE(actual.back(), '\\');
+
+  // Assert shortening another long path, and that the result is lowercased.
+  string dirname(JoinPath(short_tmpdir, "LONGpathNAME"));
+  ASSERT_EQ(0, mkdir(dirname.c_str()));
+  ASSERT_TRUE(PathExists(dirname));
+  ASSERT_TRUE(AsShortWindowsPath(dirname, &actual, nullptr));
+  ASSERT_EQ(short_tmpdir + "\\longpa~1", actual);
+
+  // Assert shortening non-existent paths.
+  ASSERT_TRUE(AsShortWindowsPath(JoinPath(tmpdir, "NonExistent/FOO"), &actual,
+                                 nullptr));
+  ASSERT_EQ(short_tmpdir + "\\nonexistent\\foo", actual);
+}
+
+TEST(PathWindowsTest, TestMsysRootRetrieval) {
+  wstring actual;
+
+  // We just need "bin/<something>" or "usr/bin/<something>".
+  // Forward slashes are converted to backslashes.
+  SetEnvironmentVariableA("BAZEL_SH", "c:/foo\\bin/some_bash.exe");
+
+  string error;
+  ASSERT_FALSE(AsWindowsPath("/blah", &actual, &error));
+  EXPECT_TRUE(error.find("Unix-style") != string::npos);
+
+  SetEnvironmentVariableA("BAZEL_SH", "c:/tools/msys64/usr/bin/bash.exe");
+  ASSERT_FALSE(AsWindowsPath("/blah", &actual, &error));
+  EXPECT_TRUE(error.find("Unix-style") != string::npos);
+}
+
+TEST(PathWindowsTest, IsWindowsDevNullTest) {
+  ASSERT_TRUE(IsDevNull("nul"));
+  ASSERT_TRUE(IsDevNull("NUL"));
+  ASSERT_TRUE(IsDevNull("nuL"));
+  ASSERT_TRUE(IsDevNull("/dev/null"));
+  ASSERT_FALSE(IsDevNull("/Dev/Null"));
+  ASSERT_FALSE(IsDevNull("dev/null"));
+  ASSERT_FALSE(IsDevNull("/dev/nul"));
+  ASSERT_FALSE(IsDevNull("/dev/nulll"));
+  ASSERT_FALSE(IsDevNull("nu"));
+  ASSERT_FALSE(IsDevNull(NULL));
+  ASSERT_FALSE(IsDevNull(""));
+}
+
+TEST(PathWindowsTest, ConvertPathTest) {
+  EXPECT_EQ("c:\\foo", ConvertPath("C:\\FOO"));
+  EXPECT_EQ("c:\\", ConvertPath("c:/"));
+  EXPECT_EQ("c:\\foo\\bar", ConvertPath("c:/../foo\\BAR\\.\\"));
+  EXPECT_EQ("nul", MakeAbsolute("NUL"));
+  EXPECT_EQ("nul", MakeAbsolute("nul"));
+  EXPECT_EQ("nul", MakeAbsolute("/dev/null"));
+}
+
+TEST(PathWindowsTest, TestMakeAbsolute) {
+  EXPECT_EQ("c:\\foo\\bar", MakeAbsolute("C:\\foo\\BAR"));
+  EXPECT_EQ("c:\\foo\\bar", MakeAbsolute("C:/foo/bar"));
+  EXPECT_EQ("c:\\foo\\bar", MakeAbsolute("C:\\foo\\bar\\"));
+  EXPECT_EQ("c:\\foo\\bar", MakeAbsolute("C:/foo/bar/"));
+  EXPECT_EQ(blaze_util::AsLower(blaze_util::GetCwd()) + "\\foo",
+            MakeAbsolute("foo"));
+  EXPECT_EQ("nul", MakeAbsolute("NUL"));
+  EXPECT_EQ("nul", MakeAbsolute("Nul"));
+  EXPECT_EQ("nul", MakeAbsolute("nul"));
+  EXPECT_EQ(blaze_util::AsLower(blaze_util::GetCwd()), MakeAbsolute(""));
+  EXPECT_EQ("nul", MakeAbsolute("/dev/null"));
+}
+
+}  // namespace blaze_util
diff --git a/src/test/cpp/workspace_layout_test.cc b/src/test/cpp/workspace_layout_test.cc
index 8ac4fcb..4e17d64 100644
--- a/src/test/cpp/workspace_layout_test.cc
+++ b/src/test/cpp/workspace_layout_test.cc
@@ -20,6 +20,7 @@
 
 #include "src/main/cpp/blaze_util_platform.h"
 #include "src/main/cpp/util/file.h"
+#include "src/main/cpp/util/path.h"
 #include "googletest/include/gtest/gtest.h"
 
 namespace blaze {
diff --git a/src/test/shell/bazel/testdata/embedded_tools_srcs_deps b/src/test/shell/bazel/testdata/embedded_tools_srcs_deps
index 47f15a1..10a6141 100644
--- a/src/test/shell/bazel/testdata/embedded_tools_srcs_deps
+++ b/src/test/shell/bazel/testdata/embedded_tools_srcs_deps
@@ -30,7 +30,7 @@
 //src/main/cpp/util:util
 //src/main/cpp/util:numbers
 //src/main/cpp/util:md5
-//src/main/cpp/util:file
+//src/main/cpp/util:filesystem
 //src/main/native/windows:lib-file
 //src/main/native/windows:lib-util
 //src/main/cpp/util:strings