src/test/cpp/util/file_windows_test.cc

// 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.h"
#include "src/main/cpp/util/file_platform.h"
#include "src/main/native/windows_file_operations.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 std::string;
using std::unique_ptr;
using std::wstring;

// Methods defined in file_windows.cc that are only visible for testing.
bool AsWindowsPath(const string& path, wstring* result);
bool AsWindowsPathWithUncPrefix(const string& path, wstring* wpath);
void ResetMsysRootForTesting();
string NormalizeWindowsPath(string path);

class FileWindowsTest : public ::testing::Test {
 public:
  void TearDown() override { DeleteAllUnder(GetTestTmpDirW()); }
};

// This is a macro so the assertions will have the correct line number.
#define GET_TEST_TMPDIR(/* string& */ result)                            \
  {                                                                      \
    char buf[MAX_PATH] = {0};                                            \
    DWORD len = ::GetEnvironmentVariableA("TEST_TMPDIR", buf, MAX_PATH); \
    result = buf;                                                        \
    ASSERT_GT(result.size(), 0);                                         \
  }

#define CREATE_JUNCTION(/* const string& */ name, /* const string& */ target) \
  {                                                                           \
    wstring wname;                                                            \
    wstring wtarget;                                                          \
    EXPECT_TRUE(AsWindowsPath(name, &wname));                                 \
    EXPECT_TRUE(AsWindowsPath(target, &wtarget));                             \
    EXPECT_EQ("", windows_util::CreateJunction(wname, wtarget));              \
  }

// Asserts that dir1 can be created with some content, and dir2 doesn't exist.
static void AssertTearDown(const WCHAR* dir1, const WCHAR* dir2) {
  wstring wtmpdir(GetTestTmpDirW());
  wstring dir1str(wtmpdir + L"\\" + dir1);
  wstring subdir(dir1str + L"\\subdir");
  wstring wfile(subdir + L"\\hello.txt");
  EXPECT_TRUE(::CreateDirectoryW(dir1str.c_str(), NULL));
  EXPECT_TRUE(::CreateDirectoryW(subdir.c_str(), NULL));
  EXPECT_TRUE(CreateDummyFile(wfile));
  EXPECT_NE(::GetFileAttributesW(wfile.c_str()), INVALID_FILE_ATTRIBUTES);
  ASSERT_EQ(::GetFileAttributesW((wtmpdir + L"\\" + dir2).c_str()),
            INVALID_FILE_ATTRIBUTES);
}

// One half of the teardown test: assert that test.teardown.b was cleaned up.
TEST_F(FileWindowsTest, TestTearDownA) {
  AssertTearDown(L"test.teardown.a", L"test.teardown.b");
}

// Other half of the teardown test: assert that test.teardown.a was cleaned up.
TEST_F(FileWindowsTest, TestTearDownB) {
  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:\\msys\\some\\long\\path\\bash.exe");
  ResetMsysRootForTesting();
  wstring actual;

  ASSERT_TRUE(AsWindowsPath("", &actual));
  ASSERT_EQ(wstring(L""), actual);

  ASSERT_TRUE(AsWindowsPath("", &actual));
  ASSERT_EQ(wstring(L""), actual);

  ASSERT_TRUE(AsWindowsPath("foo/bar", &actual));
  ASSERT_EQ(wstring(L"foo\\bar"), actual);

  ASSERT_TRUE(AsWindowsPath("c:", &actual));
  ASSERT_EQ(wstring(L"c:\\"), actual);

  ASSERT_TRUE(AsWindowsPath("c:/", &actual));
  ASSERT_EQ(wstring(L"c:\\"), actual);

  ASSERT_TRUE(AsWindowsPath("c:\\", &actual));
  ASSERT_EQ(wstring(L"c:\\"), actual);

  ASSERT_TRUE(AsWindowsPath("\\\\?\\c:\\", &actual));
  ASSERT_EQ(wstring(L"c:\\"), actual);

  ASSERT_TRUE(AsWindowsPath("\\\\?\\c://../foo", &actual));
  ASSERT_EQ(wstring(L"c:\\foo"), actual);

  ASSERT_TRUE(AsWindowsPath("/dev/null", &actual));
  ASSERT_EQ(wstring(L"NUL"), actual);

  ASSERT_TRUE(AsWindowsPath("Nul", &actual));
  ASSERT_EQ(wstring(L"NUL"), actual);

  ASSERT_TRUE(AsWindowsPath("/c", &actual));
  ASSERT_EQ(wstring(L"c:\\"), actual);

  ASSERT_TRUE(AsWindowsPath("/c/", &actual));
  ASSERT_EQ(wstring(L"c:\\"), actual);

  ASSERT_TRUE(AsWindowsPath("/c/blah", &actual));
  ASSERT_EQ(wstring(L"c:\\blah"), actual);

  ASSERT_TRUE(AsWindowsPath("/d/progra~1/micros~1", &actual));
  ASSERT_EQ(wstring(L"d:\\progra~1\\micros~1"), actual);

  ASSERT_TRUE(AsWindowsPath("/foo", &actual));
  ASSERT_EQ(wstring(L"c:\\msys\\foo"), actual);

  wstring wlongpath(L"\\dummy_long_path");
  string longpath("dummy_long_path/");
  while (longpath.size() <= MAX_PATH) {
    wlongpath += wlongpath;
    longpath += longpath;
  }
  wlongpath = wstring(L"c:") + wlongpath;
  longpath = string("/c/") + longpath;
  ASSERT_TRUE(AsWindowsPath(longpath, &actual));
  ASSERT_EQ(wlongpath, actual);
}

TEST_F(FileWindowsTest, TestAsShortWindowsPath) {
  string actual;
  ASSERT_TRUE(AsShortWindowsPath("/dev/null", &actual));
  ASSERT_EQ(string("NUL"), actual);

  ASSERT_TRUE(AsShortWindowsPath("nul", &actual));
  ASSERT_EQ(string("NUL"), actual);

  ASSERT_TRUE(AsShortWindowsPath("C://", &actual));
  ASSERT_EQ(string("c:\\"), actual);
  ASSERT_TRUE(AsShortWindowsPath("/C//", &actual));
  ASSERT_EQ(string("c:\\"), actual);

  // 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));
  ASSERT_EQ(string("a:\\"), actual);
  ASSERT_TRUE(AsShortWindowsPath("/A//", &actual));
  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));
  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));
  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));
  ASSERT_EQ(short_tmpdir + "\\longpa~1", actual);

  // Assert shortening non-existent paths.
  ASSERT_TRUE(AsShortWindowsPath(JoinPath(tmpdir, "NonExistent/FOO"), &actual));
  ASSERT_EQ(short_tmpdir + "\\nonexistent\\foo", actual);
  // Assert shortening non-existent root paths.
  ASSERT_TRUE(AsShortWindowsPath("/c/NonExistent/FOO", &actual));
  ASSERT_EQ("c:\\nonexistent\\foo", actual);
}

TEST_F(FileWindowsTest, TestMsysRootRetrieval) {
  wstring actual;

  SetEnvironmentVariableA("BAZEL_SH", "c:/foo/msys/bar/qux.exe");
  ResetMsysRootForTesting();
  ASSERT_TRUE(AsWindowsPath("/blah", &actual));
  ASSERT_EQ(wstring(L"c:\\foo\\msys\\blah"), actual);

  SetEnvironmentVariableA("BAZEL_SH", "c:/foo/MSYS64/bar/qux.exe");
  ResetMsysRootForTesting();
  ASSERT_TRUE(AsWindowsPath("/blah", &actual));
  ASSERT_EQ(wstring(L"c:\\foo\\msys64\\blah"), actual);

  SetEnvironmentVariableA("BAZEL_SH", "c:/qux.exe");
  ResetMsysRootForTesting();
  ASSERT_FALSE(AsWindowsPath("/blah", &actual));

  SetEnvironmentVariableA("BAZEL_SH", nullptr);
  ResetMsysRootForTesting();
}

TEST_F(FileWindowsTest, TestPathExistsWindows) {
  ASSERT_FALSE(PathExists(""));
  ASSERT_TRUE(PathExists("."));
  ASSERT_FALSE(PathExists("non.existent"));
  ASSERT_TRUE(PathExists("/dev/null"));
  ASSERT_TRUE(PathExists("Nul"));

  string tmpdir;
  GET_TEST_TMPDIR(tmpdir);
  ASSERT_TRUE(PathExists(tmpdir));

  // Create a fake msys root. We'll also use it as a junction target.
  string fake_msys_root(tmpdir + "/fake_msys");
  ASSERT_EQ(0, mkdir(fake_msys_root.c_str()));
  ASSERT_TRUE(PathExists(fake_msys_root));

  // Set the BAZEL_SH root so we can resolve MSYS paths.
  SetEnvironmentVariableA("BAZEL_SH",
                          (fake_msys_root + "/fake_bash.exe").c_str());
  ResetMsysRootForTesting();

  // Assert existence check for MSYS paths.
  ASSERT_FALSE(PathExists("/this/should/not/exist/mkay"));
  ASSERT_TRUE(PathExists("/"));

  // Create a junction pointing to an existing directory.
  CREATE_JUNCTION(tmpdir + "/junc1", fake_msys_root);
  ASSERT_TRUE(PathExists(fake_msys_root));
  ASSERT_TRUE(PathExists(JoinPath(tmpdir, "junc1")));

  // Create a junction pointing to a non-existent directory.
  CREATE_JUNCTION(tmpdir + "/junc2", fake_msys_root + "/i.dont.exist");
  ASSERT_FALSE(PathExists(JoinPath(fake_msys_root, "i.dont.exist")));
  ASSERT_FALSE(PathExists(JoinPath(tmpdir, "junc2")));
}

TEST_F(FileWindowsTest, TestIsDirectory) {
  ASSERT_FALSE(IsDirectory(""));
  ASSERT_FALSE(IsDirectory("/dev/null"));
  ASSERT_FALSE(IsDirectory("Nul"));

  string tmpdir;
  GET_TEST_TMPDIR(tmpdir);
  ASSERT_TRUE(IsDirectory(tmpdir));
  ASSERT_TRUE(IsDirectory("C:\\"));
  ASSERT_TRUE(IsDirectory("C:/"));
  ASSERT_TRUE(IsDirectory("/c"));

  ASSERT_FALSE(IsDirectory("non.existent"));
  // Create a directory under `tempdir`, verify that IsDirectory reports true.
  // Call it msys_dir1 so we can also use it as a mock msys root.
  string dir1(JoinPath(tmpdir, "msys_dir1"));
  ASSERT_EQ(0, mkdir(dir1.c_str()));
  ASSERT_TRUE(IsDirectory(dir1));

  // Use dir1 as the mock msys root, verify that IsDirectory works for a MSYS
  // path.
  SetEnvironmentVariableA("BAZEL_SH", JoinPath(dir1, "bash.exe").c_str());
  ResetMsysRootForTesting();
  ASSERT_TRUE(IsDirectory("/"));

  // Verify that IsDirectory works for a junction.
  string junc1(JoinPath(tmpdir, "junc1"));
  CREATE_JUNCTION(junc1, dir1);
  ASSERT_TRUE(IsDirectory(junc1));

  ASSERT_EQ(0, rmdir(dir1.c_str()));
  ASSERT_FALSE(IsDirectory(dir1));
  ASSERT_FALSE(IsDirectory(junc1));
}

TEST_F(FileWindowsTest, TestUnlinkPath) {
  ASSERT_FALSE(UnlinkPath("/dev/null"));
  ASSERT_FALSE(UnlinkPath("Nul"));

  string tmpdir;
  GET_TEST_TMPDIR(tmpdir);

  // Create a directory under `tempdir`, a file inside it, and a junction
  // pointing to it.
  string dir1(JoinPath(tmpdir, "dir1"));
  ASSERT_EQ(0, mkdir(dir1.c_str()));
  AutoFileStream fh(fopen(JoinPath(dir1, "foo.txt").c_str(), "wt"));
  EXPECT_TRUE(fh.IsOpen());
  ASSERT_LT(0, fprintf(fh, "hello\n"));
  fh.Close();
  string junc1(JoinPath(tmpdir, "junc1"));
  CREATE_JUNCTION(junc1, dir1);
  ASSERT_TRUE(PathExists(junc1));
  ASSERT_TRUE(PathExists(JoinPath(junc1, "foo.txt")));

  // Non-existent files cannot be unlinked.
  ASSERT_FALSE(UnlinkPath("does.not.exist"));
  // Directories cannot be unlinked.
  ASSERT_FALSE(UnlinkPath(dir1));
  // Junctions can be unlinked, even if the pointed directory is not empty.
  ASSERT_TRUE(UnlinkPath(JoinPath(junc1, "foo.txt")));
  // Files can be unlinked.
  ASSERT_TRUE(UnlinkPath(junc1));
}

TEST_F(FileWindowsTest, TestMakeDirectories) {
  string tmpdir;
  GET_TEST_TMPDIR(tmpdir);
  ASSERT_LT(0, tmpdir.size());

  SetEnvironmentVariableA(
      "BAZEL_SH", (JoinPath(tmpdir, "fake_msys/fake_bash.exe")).c_str());
  ResetMsysRootForTesting();
  ASSERT_EQ(0, mkdir(JoinPath(tmpdir, "fake_msys").c_str()));
  ASSERT_TRUE(IsDirectory(JoinPath(tmpdir, "fake_msys")));

  // Test that we can create come directories, can't create others.
  ASSERT_FALSE(MakeDirectories("", 0777));
  ASSERT_FALSE(MakeDirectories("/dev/null", 0777));
  ASSERT_FALSE(MakeDirectories("c:/", 0777));
  ASSERT_FALSE(MakeDirectories("c:\\", 0777));
  ASSERT_FALSE(MakeDirectories("/", 0777));
  ASSERT_TRUE(MakeDirectories("/foo", 0777));
  ASSERT_TRUE(MakeDirectories(".", 0777));
  ASSERT_TRUE(MakeDirectories(tmpdir, 0777));
  ASSERT_TRUE(MakeDirectories(JoinPath(tmpdir, "dir1/dir2/dir3"), 0777));
  ASSERT_TRUE(MakeDirectories(string("\\\\?\\") + tmpdir + "/dir4/dir5", 0777));
}

TEST_F(FileWindowsTest, TestCanAccess) {
  ASSERT_FALSE(CanReadFile("C:/windows/this/should/not/exist/mkay"));
  ASSERT_FALSE(CanExecuteFile("C:/this/should/not/exist/mkay"));
  ASSERT_FALSE(CanAccessDirectory("C:/this/should/not/exist/mkay"));

  ASSERT_FALSE(CanReadFile("non.existent"));
  ASSERT_FALSE(CanExecuteFile("non.existent"));
  ASSERT_FALSE(CanAccessDirectory("non.existent"));

  string tmpdir;
  GET_TEST_TMPDIR(tmpdir);
  string dir(JoinPath(tmpdir, "canaccesstest"));
  ASSERT_EQ(0, mkdir(dir.c_str()));

  ASSERT_FALSE(CanReadFile(dir));
  ASSERT_FALSE(CanExecuteFile(dir));
  ASSERT_TRUE(CanAccessDirectory(dir));

  string junc(JoinPath(tmpdir, "junc1"));
  CREATE_JUNCTION(junc, dir);
  ASSERT_FALSE(CanReadFile(junc));
  ASSERT_FALSE(CanExecuteFile(junc));
  ASSERT_TRUE(CanAccessDirectory(junc));

  string file(JoinPath(dir, "foo.txt"));
  AutoFileStream fh(fopen(file.c_str(), "wt"));
  EXPECT_TRUE(fh.IsOpen());
  ASSERT_LT(0, fprintf(fh, "hello"));
  fh.Close();

  ASSERT_TRUE(CanReadFile(file));
  ASSERT_FALSE(CanExecuteFile(file));
  ASSERT_FALSE(CanAccessDirectory(file));

  ASSERT_TRUE(CanReadFile(JoinPath(junc, "foo.txt")));
  ASSERT_FALSE(CanExecuteFile(JoinPath(junc, "foo.txt")));
  ASSERT_FALSE(CanAccessDirectory(JoinPath(junc, "foo.txt")));

  string file2(JoinPath(dir, "foo.exe"));
  ASSERT_EQ(0, rename(file.c_str(), file2.c_str()));
  ASSERT_TRUE(CanReadFile(file2));
  ASSERT_TRUE(CanExecuteFile(file2));
  ASSERT_FALSE(CanAccessDirectory(file2));
}

TEST_F(FileWindowsTest, TestMakeCanonical) {
  string tmpdir;
  GET_TEST_TMPDIR(tmpdir);
  // Create some scratch directories: $TEST_TMPDIR/directory/subdirectory
  string dir1(JoinPath(tmpdir, "directory"));
  string dir2(JoinPath(dir1, "subdirectory"));
  EXPECT_TRUE(MakeDirectories(dir2, 0700));
  // Create a dummy file: $TEST_TMPDIR/directory/subdirectory/foo.txt
  string foo(JoinPath(dir2, "foo.txt"));
  wstring wfoo;
  EXPECT_TRUE(AsWindowsPathWithUncPrefix(foo, &wfoo));
  EXPECT_TRUE(CreateDummyFile(wfoo));
  EXPECT_TRUE(CanReadFile(foo));
  // Create junctions next to directory and subdirectory, pointing to them.
  // Use short paths and mixed casing to test that the canonicalization can
  // resolve these.
  //   $TEST_TMPDIR/junc12345 -> $TEST_TMPDIR/DIRECT~1
  //   $TEST_TMPDIR/junc12~1/junc67890 -> $TEST_TMPDIR/JUNC12~1/SubDir~1
  string sym1(JoinPath(tmpdir, "junc12345"));
  string sym2(JoinPath(JoinPath(tmpdir, "junc12~1"), "junc67890"));
  string sym1value(JoinPath(tmpdir, "DIRECT~1"));
  string sym2value(JoinPath(JoinPath(tmpdir, "JUNC12~1"), "SubDir~1"));
  CREATE_JUNCTION(sym1, sym1value);
  CREATE_JUNCTION(sym2, sym2value);
  // Expect that $TEST_TMPDIR/sym1/sym2/foo.txt is readable.
  string symfoo(JoinPath(sym2, "foo.txt"));
  EXPECT_TRUE(CanReadFile(symfoo));
  // Assert the canonical path of foo.txt via the real path and via sym2.
  // The latter contains at least two junction components, shortened paths, and
  // mixed casing.
  string dircanon(MakeCanonical(foo.c_str()));
  string symcanon(MakeCanonical(symfoo.c_str()));
  string expected("directory\\subdirectory\\foo.txt");
  ASSERT_NE(symcanon, "");
  ASSERT_EQ(symcanon.find(expected), symcanon.size() - expected.size());
  ASSERT_EQ(dircanon, symcanon);
}

}  // namespace blaze_util