diff --git a/tests/dirent_test.cpp b/tests/dirent_test.cpp
new file mode 100644
index 0000000..4e364d3
--- /dev/null
+++ b/tests/dirent_test.cpp
@@ -0,0 +1,191 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ *
+ * 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 <gtest/gtest.h>
+
+#include <dirent.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <algorithm>
+#include <set>
+#include <string>
+
+#ifdef __BIONIC__
+static int my_alphasort(const dirent** lhs, const dirent** rhs) {
+  return alphasort(lhs, rhs);
+}
+#endif
+
+static void CheckProcSelf(std::set<std::string>& names) {
+  // We have a good idea of what should be in /proc/self.
+  ASSERT_TRUE(names.find(".") != names.end());
+  ASSERT_TRUE(names.find("..") != names.end());
+  ASSERT_TRUE(names.find("cmdline") != names.end());
+  ASSERT_TRUE(names.find("fd") != names.end());
+  ASSERT_TRUE(names.find("stat") != names.end());
+}
+
+TEST(dirent, scandir) {
+  // Get everything from /proc/self...
+  dirent** entries;
+#ifdef __BIONIC__
+  int entry_count = scandir("/proc/self", &entries, NULL, my_alphasort);
+#else
+  int entry_count = scandir("/proc/self", &entries, NULL, alphasort);
+#endif
+  ASSERT_GE(entry_count, 0);
+
+  // Turn the directory entries into a set and vector of the names.
+  std::set<std::string> name_set;
+  std::vector<std::string> unsorted_name_list;
+  for (size_t i = 0; i < static_cast<size_t>(entry_count); ++i) {
+    name_set.insert(entries[i]->d_name);
+    unsorted_name_list.push_back(entries[i]->d_name);
+    free(entries[i]);
+  }
+  free(entries);
+
+  // No duplicates.
+  ASSERT_EQ(name_set.size(), unsorted_name_list.size());
+
+  // All entries sorted.
+  std::vector<std::string> sorted_name_list(unsorted_name_list);
+  std::sort(sorted_name_list.begin(), sorted_name_list.end());
+  ASSERT_EQ(sorted_name_list, unsorted_name_list);
+
+  CheckProcSelf(name_set);
+}
+
+TEST(dirent, fdopendir_invalid) {
+  ASSERT_TRUE(fdopendir(-1) == NULL);
+  ASSERT_EQ(errno, EBADF);
+
+  int fd = open("/dev/null", O_RDONLY);
+  ASSERT_NE(fd, -1);
+  ASSERT_TRUE(fdopendir(fd) == NULL);
+  ASSERT_EQ(errno, ENOTDIR);
+  close(fd);
+}
+
+TEST(dirent, fdopendir) {
+  int fd = open("/proc/self", O_RDONLY);
+  DIR* d = fdopendir(fd);
+  ASSERT_TRUE(d != NULL);
+  dirent* e = readdir(d);
+  ASSERT_STREQ(e->d_name, ".");
+  ASSERT_EQ(closedir(d), 0);
+
+  // fdopendir(3) took ownership, so closedir(3) closed our fd.
+  ASSERT_EQ(close(fd), -1);
+  ASSERT_EQ(errno, EBADF);
+}
+
+TEST(dirent, opendir_invalid) {
+  ASSERT_TRUE(opendir("/does/not/exist") == NULL);
+  ASSERT_EQ(errno, ENOENT);
+
+  ASSERT_TRUE(opendir("/dev/null") == NULL);
+  ASSERT_EQ(errno, ENOTDIR);
+}
+
+TEST(dirent, opendir) {
+  DIR* d = opendir("/proc/self");
+  ASSERT_TRUE(d != NULL);
+  dirent* e = readdir(d);
+  ASSERT_STREQ(e->d_name, ".");
+  ASSERT_EQ(closedir(d), 0);
+}
+
+TEST(dirent, closedir_invalid) {
+  DIR* d = NULL;
+  ASSERT_EQ(closedir(d), -1);
+  ASSERT_EQ(errno, EINVAL);
+}
+
+TEST(dirent, closedir) {
+  DIR* d = opendir("/proc/self");
+  ASSERT_TRUE(d != NULL);
+  ASSERT_EQ(closedir(d), 0);
+}
+
+TEST(dirent, readdir) {
+  DIR* d = opendir("/proc/self");
+  ASSERT_TRUE(d != NULL);
+  std::set<std::string> name_set;
+  errno = 0;
+  dirent* e;
+  while ((e = readdir(d)) != NULL) {
+    name_set.insert(e->d_name);
+  }
+  // Reading to the end of the directory is not an error.
+  // readdir(3) returns NULL, but leaves errno as 0.
+  ASSERT_EQ(errno, 0);
+  ASSERT_EQ(closedir(d), 0);
+
+  CheckProcSelf(name_set);
+}
+
+TEST(dirent, readdir_r) {
+  DIR* d = opendir("/proc/self");
+  ASSERT_TRUE(d != NULL);
+  std::set<std::string> name_set;
+  errno = 0;
+  dirent storage;
+  dirent* e = NULL;
+  while (readdir_r(d, &storage, &e) == 0 && e != NULL) {
+    name_set.insert(e->d_name);
+  }
+  // Reading to the end of the directory is not an error.
+  // readdir_r(3) returns NULL, but leaves errno as 0.
+  ASSERT_EQ(errno, 0);
+  ASSERT_EQ(closedir(d), 0);
+
+  CheckProcSelf(name_set);
+}
+
+TEST(dirent, rewinddir) {
+  DIR* d = opendir("/proc/self");
+  ASSERT_TRUE(d != NULL);
+
+  // Get all the names once...
+  std::vector<std::string> pass1;
+  dirent* e;
+  while ((e = readdir(d)) != NULL) {
+    pass1.push_back(e->d_name);
+  }
+
+  // ...rewind...
+  rewinddir(d);
+
+  // ...and get all the names again.
+  std::vector<std::string> pass2;
+  while ((e = readdir(d)) != NULL) {
+    pass2.push_back(e->d_name);
+  }
+
+  ASSERT_EQ(closedir(d), 0);
+
+  // We should have seen the same names in the same order both times.
+  ASSERT_EQ(pass1.size(), pass2.size());
+  for (size_t i = 0; i < pass1.size(); ++i) {
+    ASSERT_EQ(pass1[i], pass2[i]);
+  }
+}