diff --git a/cmds/installd/tests/Android.bp b/cmds/installd/tests/Android.bp
index 4cde7e3..51f7716 100644
--- a/cmds/installd/tests/Android.bp
+++ b/cmds/installd/tests/Android.bp
@@ -188,3 +188,23 @@
         "libotapreoptparameters",
     ],
 }
+
+cc_test {
+    name: "installd_file_test",
+    test_suites: ["device-tests"],
+    clang: true,
+    srcs: ["installd_file_test.cpp"],
+    cflags: [
+        "-Wall",
+        "-Werror",
+    ],
+    shared_libs: [
+        "libbase",
+        "libcutils",
+        "libutils",
+    ],
+    static_libs: [
+        "libinstalld",
+        "liblog",
+    ],
+}
diff --git a/cmds/installd/tests/installd_file_test.cpp b/cmds/installd/tests/installd_file_test.cpp
new file mode 100644
index 0000000..00fb308
--- /dev/null
+++ b/cmds/installd/tests/installd_file_test.cpp
@@ -0,0 +1,521 @@
+/*
+ * Copyright (C) 2021 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 <android-base/file.h>
+#include <android-base/logging.h>
+#include <android-base/stringprintf.h>
+#include <gtest/gtest.h>
+#include <log/log.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "restorable_file.h"
+#include "unique_file.h"
+#include "utils.h"
+
+#undef LOG_TAG
+#define LOG_TAG "installd_file_test"
+
+namespace {
+
+constexpr char kFileTestDir[] = "/data/local/tmp/installd_file_test_data";
+constexpr char kTmpFileSuffix[] = ".tmp";
+constexpr char kBackupFileSuffix[] = ".backup";
+
+void UnlinkWithAssert(const std::string& path) {
+    ASSERT_EQ(0, unlink(path.c_str()));
+}
+
+} // namespace
+
+namespace android {
+namespace installd {
+
+// Add these as macros as functions make it hard to tell where the failure has happened.
+#define ASSERT_FILE_NOT_EXISTING(path)           \
+    {                                            \
+        struct stat st;                          \
+        ASSERT_NE(0, ::stat(path.c_str(), &st)); \
+    }
+#define ASSERT_FILE_EXISTING(path)               \
+    {                                            \
+        struct stat st;                          \
+        ASSERT_EQ(0, ::stat(path.c_str(), &st)); \
+    }
+#define ASSERT_FILE_CONTENT(path, expectedContent) ASSERT_EQ(expectedContent, ReadTestFile(path))
+#define ASSERT_FILE_OPEN(path, fd)       \
+    {                                    \
+        fd = open(path.c_str(), O_RDWR); \
+        ASSERT_TRUE(fd >= 0);            \
+    }
+#define ASSERT_WRITE_TO_FD(fd, content) \
+    ASSERT_TRUE(android::base::WriteStringToFd(content, android::base::borrowed_fd(fd)))
+
+class FileTest : public testing::Test {
+protected:
+    virtual void SetUp() {
+        setenv("ANDROID_LOG_TAGS", "*:v", 1);
+        android::base::InitLogging(nullptr);
+
+        ASSERT_EQ(0, create_dir_if_needed(kFileTestDir, 0777));
+    }
+
+    virtual void TearDown() {
+        system(android::base::StringPrintf("rm -rf %s", kFileTestDir).c_str());
+    }
+
+    std::string GetTestFilePath(const std::string& fileName) {
+        return android::base::StringPrintf("%s/%s", kFileTestDir, fileName.c_str());
+    }
+
+    void CreateTestFileWithContents(const std::string& path, const std::string& content) {
+        ALOGI("CreateTestFileWithContents:%s", path.c_str());
+        ASSERT_TRUE(android::base::WriteStringToFile(content, path));
+    }
+
+    std::string GetTestName() {
+        std::string name(testing::UnitTest::GetInstance()->current_test_info()->name());
+        return name;
+    }
+
+    std::string ReadTestFile(const std::string& path) {
+        std::string content;
+        bool r = android::base::ReadFileToString(path, &content);
+        if (!r) {
+            PLOG(ERROR) << "Cannot read file:" << path;
+        }
+        return content;
+    }
+};
+
+TEST_F(FileTest, TestUniqueFileMoveConstruction) {
+    const int fd = 101;
+    std::string testFile = GetTestFilePath(GetTestName());
+    UniqueFile uf1(fd, testFile);
+    uf1.DisableAutoClose();
+
+    UniqueFile uf2(std::move(uf1));
+
+    ASSERT_EQ(fd, uf2.fd());
+    ASSERT_EQ(testFile, uf2.path());
+}
+
+TEST_F(FileTest, TestUniqueFileAssignment) {
+    const int fd1 = 101;
+    const int fd2 = 102;
+    std::string testFile1 = GetTestFilePath(GetTestName());
+    std::string testFile2 = GetTestFilePath(GetTestName() + "2");
+
+    UniqueFile uf1(fd1, testFile1);
+    uf1.DisableAutoClose();
+
+    UniqueFile uf2(fd2, testFile2);
+    uf2.DisableAutoClose();
+
+    ASSERT_EQ(fd2, uf2.fd());
+    ASSERT_EQ(testFile2, uf2.path());
+
+    uf2 = std::move(uf1);
+
+    ASSERT_EQ(fd1, uf2.fd());
+    ASSERT_EQ(testFile1, uf2.path());
+}
+
+TEST_F(FileTest, TestUniqueFileCleanup) {
+    std::string testFile = GetTestFilePath(GetTestName());
+    CreateTestFileWithContents(testFile, "OriginalContent");
+
+    int fd;
+    ASSERT_FILE_OPEN(testFile, fd);
+
+    { UniqueFile uf = UniqueFile(fd, testFile, UnlinkWithAssert); }
+
+    ASSERT_FILE_NOT_EXISTING(testFile);
+}
+
+TEST_F(FileTest, TestUniqueFileNoCleanup) {
+    std::string testFile = GetTestFilePath(GetTestName());
+    CreateTestFileWithContents(testFile, "OriginalContent");
+
+    int fd;
+    ASSERT_FILE_OPEN(testFile, fd);
+
+    {
+        UniqueFile uf = UniqueFile(fd, testFile, UnlinkWithAssert);
+        uf.DisableCleanup();
+    }
+
+    ASSERT_FILE_CONTENT(testFile, "OriginalContent");
+}
+
+TEST_F(FileTest, TestUniqueFileFd) {
+    std::string testFile = GetTestFilePath(GetTestName());
+    CreateTestFileWithContents(testFile, "OriginalContent");
+
+    int fd;
+    ASSERT_FILE_OPEN(testFile, fd);
+
+    UniqueFile uf(fd, testFile, UnlinkWithAssert);
+
+    ASSERT_EQ(fd, uf.fd());
+
+    uf.reset();
+
+    ASSERT_EQ(-1, uf.fd());
+}
+
+TEST_F(FileTest, TestRestorableFileMoveConstruction) {
+    std::string testFile = GetTestFilePath(GetTestName());
+
+    RestorableFile rf1 = RestorableFile::CreateWritableFile(testFile, 0600);
+    int fd = rf1.fd();
+
+    RestorableFile rf2(std::move(rf1));
+
+    ASSERT_EQ(fd, rf2.fd());
+    ASSERT_EQ(testFile, rf2.path());
+}
+
+TEST_F(FileTest, TestRestorableFileAssignment) {
+    std::string testFile1 = GetTestFilePath(GetTestName());
+    std::string testFile2 = GetTestFilePath(GetTestName() + "2");
+
+    RestorableFile rf1 = RestorableFile::CreateWritableFile(testFile1, 0600);
+    int fd1 = rf1.fd();
+
+    RestorableFile rf2 = RestorableFile::CreateWritableFile(testFile2, 0600);
+    int fd2 = rf2.fd();
+
+    ASSERT_EQ(fd2, rf2.fd());
+    ASSERT_EQ(testFile2, rf2.path());
+
+    rf2 = std::move(rf1);
+
+    ASSERT_EQ(fd1, rf2.fd());
+    ASSERT_EQ(testFile1, rf2.path());
+}
+
+TEST_F(FileTest, TestRestorableFileVerifyUniqueFileWithReset) {
+    std::string testFile = GetTestFilePath(GetTestName());
+    std::string tmpFile = testFile + kTmpFileSuffix;
+
+    {
+        RestorableFile rf = RestorableFile::CreateWritableFile(testFile, 0600);
+
+        ASSERT_FILE_EXISTING(tmpFile);
+
+        const UniqueFile& uf = rf.GetUniqueFile();
+
+        ASSERT_EQ(rf.fd(), uf.fd());
+        ASSERT_EQ(rf.path(), uf.path());
+
+        rf.reset();
+
+        ASSERT_EQ(rf.fd(), uf.fd());
+        ASSERT_EQ(rf.path(), uf.path());
+        ASSERT_EQ(-1, rf.fd());
+        ASSERT_TRUE(rf.path().empty());
+    }
+}
+
+TEST_F(FileTest, TestRestorableFileVerifyUniqueFileWithCommit) {
+    std::string testFile = GetTestFilePath(GetTestName());
+    std::string tmpFile = testFile + kTmpFileSuffix;
+    std::string backupFile = testFile + kBackupFileSuffix;
+
+    {
+        RestorableFile rf = RestorableFile::CreateWritableFile(testFile, 0600);
+
+        ASSERT_FILE_EXISTING(tmpFile);
+
+        const UniqueFile& uf = rf.GetUniqueFile();
+
+        ASSERT_EQ(rf.fd(), uf.fd());
+        ASSERT_EQ(rf.path(), uf.path());
+
+        ASSERT_TRUE(rf.CreateBackupFile());
+
+        ASSERT_FILE_NOT_EXISTING(backupFile);
+
+        rf.CommitWorkFile();
+
+        ASSERT_EQ(rf.fd(), uf.fd());
+        ASSERT_EQ(rf.path(), uf.path());
+        ASSERT_EQ(-1, rf.fd());
+        ASSERT_EQ(testFile, rf.path());
+    }
+}
+
+TEST_F(FileTest, TestRestorableFileNewFileNotCommitted) {
+    std::string testFile = GetTestFilePath(GetTestName());
+    std::string tmpFile = testFile + kTmpFileSuffix;
+
+    {
+        RestorableFile rf = RestorableFile::CreateWritableFile(testFile, 0600);
+
+        ASSERT_FILE_EXISTING(tmpFile);
+        ASSERT_FILE_NOT_EXISTING(testFile);
+
+        ASSERT_WRITE_TO_FD(rf.fd(), "NewContent");
+
+        ASSERT_FILE_CONTENT(tmpFile, "NewContent");
+    }
+
+    ASSERT_FILE_NOT_EXISTING(tmpFile);
+    ASSERT_FILE_NOT_EXISTING(testFile);
+}
+
+TEST_F(FileTest, TestRestorableFileNotCommittedWithOriginal) {
+    std::string testFile = GetTestFilePath(GetTestName());
+    std::string tmpFile = testFile + kTmpFileSuffix;
+    CreateTestFileWithContents(testFile, "OriginalContent");
+
+    {
+        RestorableFile rf = RestorableFile::CreateWritableFile(testFile, 0600);
+        ASSERT_WRITE_TO_FD(rf.fd(), "NewContent");
+
+        ASSERT_FILE_CONTENT(tmpFile, "NewContent");
+        ASSERT_FILE_EXISTING(testFile);
+    }
+
+    ASSERT_FILE_NOT_EXISTING(tmpFile);
+    ASSERT_FILE_CONTENT(testFile, "OriginalContent");
+}
+
+TEST_F(FileTest, TestRestorableFileNotCommittedWithOriginalAndOldTmp) {
+    std::string testFile = GetTestFilePath(GetTestName());
+    std::string tmpFile = testFile + kTmpFileSuffix;
+    CreateTestFileWithContents(testFile, "OriginalContent");
+    CreateTestFileWithContents(testFile + kTmpFileSuffix, "OldTmp");
+
+    {
+        RestorableFile rf = RestorableFile::CreateWritableFile(testFile, 0600);
+        ASSERT_WRITE_TO_FD(rf.fd(), "NewContent");
+
+        ASSERT_FILE_CONTENT(tmpFile, "NewContent");
+        ASSERT_FILE_EXISTING(testFile);
+    }
+
+    ASSERT_FILE_NOT_EXISTING(tmpFile);
+    ASSERT_FILE_CONTENT(testFile, "OriginalContent");
+}
+
+TEST_F(FileTest, TestRestorableFileNewFileCommitted) {
+    std::string testFile = GetTestFilePath(GetTestName());
+    std::string tmpFile = testFile + kTmpFileSuffix;
+    std::string backupFile = testFile + kBackupFileSuffix;
+
+    {
+        RestorableFile rf = RestorableFile::CreateWritableFile(testFile, 0600);
+
+        ASSERT_FILE_EXISTING(tmpFile);
+        ASSERT_FILE_NOT_EXISTING(testFile);
+
+        ASSERT_WRITE_TO_FD(rf.fd(), "NewContent");
+        ASSERT_FILE_CONTENT(tmpFile, "NewContent");
+
+        ASSERT_TRUE(rf.CreateBackupFile());
+
+        ASSERT_FILE_NOT_EXISTING(backupFile);
+
+        ASSERT_TRUE(rf.CommitWorkFile());
+        rf.RemoveBackupFile();
+
+        ASSERT_FILE_CONTENT(testFile, "NewContent");
+    }
+
+    ASSERT_FILE_NOT_EXISTING(tmpFile);
+    ASSERT_FILE_NOT_EXISTING(backupFile);
+    ASSERT_FILE_CONTENT(testFile, "NewContent");
+}
+
+TEST_F(FileTest, TestRestorableFileCommittedWithOriginal) {
+    std::string testFile = GetTestFilePath(GetTestName());
+    std::string tmpFile = testFile + kTmpFileSuffix;
+    std::string backupFile = testFile + kBackupFileSuffix;
+    CreateTestFileWithContents(testFile, "OriginalContent");
+
+    {
+        RestorableFile rf = RestorableFile::CreateWritableFile(testFile, 0600);
+        ASSERT_WRITE_TO_FD(rf.fd(), "NewContent");
+        ASSERT_FILE_CONTENT(tmpFile, "NewContent");
+
+        ASSERT_TRUE(rf.CreateBackupFile());
+
+        ASSERT_FILE_NOT_EXISTING(testFile);
+        ASSERT_FILE_EXISTING(backupFile);
+
+        ASSERT_TRUE(rf.CommitWorkFile());
+
+        ASSERT_FILE_EXISTING(backupFile);
+        ASSERT_FILE_CONTENT(testFile, "NewContent");
+
+        rf.RemoveBackupFile();
+
+        ASSERT_FILE_NOT_EXISTING(backupFile);
+    }
+
+    ASSERT_FILE_NOT_EXISTING(tmpFile);
+    ASSERT_FILE_CONTENT(testFile, "NewContent");
+}
+
+TEST_F(FileTest, TestRestorableFileCommittedWithOriginalAndOldTmp) {
+    std::string testFile = GetTestFilePath(GetTestName());
+    std::string tmpFile = testFile + kTmpFileSuffix;
+    CreateTestFileWithContents(testFile, "OriginalContent");
+    CreateTestFileWithContents(testFile + kTmpFileSuffix, "OldTmp");
+
+    {
+        RestorableFile rf = RestorableFile::CreateWritableFile(testFile, 0600);
+        ASSERT_WRITE_TO_FD(rf.fd(), "NewContent");
+        ASSERT_FILE_CONTENT(tmpFile, "NewContent");
+
+        ASSERT_TRUE(rf.CommitWorkFile());
+
+        ASSERT_FILE_CONTENT(testFile, "NewContent");
+    }
+
+    ASSERT_FILE_NOT_EXISTING(tmpFile);
+    ASSERT_FILE_CONTENT(testFile, "NewContent");
+}
+
+TEST_F(FileTest, TestRestorableFileCommitFailureNoOriginal) {
+    std::string testFile = GetTestFilePath(GetTestName());
+    std::string tmpFile = testFile + kTmpFileSuffix;
+    std::string backupFile = testFile + kBackupFileSuffix;
+
+    {
+        RestorableFile rf = RestorableFile::CreateWritableFile(testFile, 0600);
+        ASSERT_WRITE_TO_FD(rf.fd(), "NewContent");
+
+        ASSERT_TRUE(rf.CreateBackupFile());
+
+        ASSERT_FILE_NOT_EXISTING(testFile);
+        ASSERT_FILE_NOT_EXISTING(backupFile);
+
+        // Now remove tmp file to force commit failure.
+        close(rf.fd());
+        ASSERT_EQ(0, unlink(tmpFile.c_str()));
+        ASSERT_FILE_NOT_EXISTING(tmpFile);
+
+        ASSERT_FALSE(rf.CommitWorkFile());
+
+        ASSERT_EQ(-1, rf.fd());
+        ASSERT_EQ(testFile, rf.path());
+        ASSERT_FILE_NOT_EXISTING(testFile);
+        ASSERT_FILE_NOT_EXISTING(tmpFile);
+
+        ASSERT_TRUE(rf.RestoreBackupFile());
+    }
+
+    ASSERT_FILE_NOT_EXISTING(testFile);
+    ASSERT_FILE_NOT_EXISTING(tmpFile);
+    ASSERT_FILE_NOT_EXISTING(backupFile);
+}
+
+TEST_F(FileTest, TestRestorableFileCommitFailureAndRollback) {
+    std::string testFile = GetTestFilePath(GetTestName());
+    std::string tmpFile = testFile + kTmpFileSuffix;
+    std::string backupFile = testFile + kBackupFileSuffix;
+    CreateTestFileWithContents(testFile, "OriginalContent");
+
+    {
+        RestorableFile rf = RestorableFile::CreateWritableFile(testFile, 0600);
+        ASSERT_WRITE_TO_FD(rf.fd(), "NewContent");
+
+        ASSERT_TRUE(rf.CreateBackupFile());
+
+        ASSERT_FILE_NOT_EXISTING(testFile);
+        ASSERT_FILE_EXISTING(backupFile);
+
+        // Now remove tmp file to force commit failure.
+        close(rf.fd());
+        ASSERT_EQ(0, unlink(tmpFile.c_str()));
+        ASSERT_FILE_NOT_EXISTING(tmpFile);
+
+        ASSERT_FALSE(rf.CommitWorkFile());
+
+        ASSERT_EQ(-1, rf.fd());
+        ASSERT_EQ(testFile, rf.path());
+        ASSERT_FILE_NOT_EXISTING(testFile);
+        ASSERT_FILE_NOT_EXISTING(tmpFile);
+        ASSERT_FILE_EXISTING(backupFile);
+
+        ASSERT_TRUE(rf.RestoreBackupFile());
+    }
+
+    ASSERT_FILE_EXISTING(testFile);
+    ASSERT_FILE_NOT_EXISTING(tmpFile);
+    ASSERT_FILE_NOT_EXISTING(backupFile);
+}
+
+TEST_F(FileTest, TestRestorableFileResetAndRemoveAllFiles) {
+    std::string testFile = GetTestFilePath(GetTestName());
+    std::string tmpFile = testFile + kTmpFileSuffix;
+    std::string backupFile = testFile + kBackupFileSuffix;
+    CreateTestFileWithContents(testFile, "OriginalContent");
+
+    {
+        RestorableFile rf = RestorableFile::CreateWritableFile(testFile, 0600);
+        ASSERT_WRITE_TO_FD(rf.fd(), "NewContent");
+
+        ASSERT_TRUE(rf.CreateBackupFile());
+
+        ASSERT_FILE_NOT_EXISTING(testFile);
+        ASSERT_FILE_EXISTING(backupFile);
+
+        rf.ResetAndRemoveAllFiles();
+
+        ASSERT_EQ(-1, rf.fd());
+        ASSERT_FILE_NOT_EXISTING(tmpFile);
+        ASSERT_FILE_NOT_EXISTING(testFile);
+        ASSERT_FILE_NOT_EXISTING(backupFile);
+    }
+
+    ASSERT_FILE_NOT_EXISTING(tmpFile);
+    ASSERT_FILE_NOT_EXISTING(testFile);
+    ASSERT_FILE_NOT_EXISTING(backupFile);
+}
+
+TEST_F(FileTest, TestRestorableFileRemoveFileAndTmpFileWithContentFile) {
+    std::string testFile = GetTestFilePath(GetTestName());
+    std::string tmpFile = testFile + kTmpFileSuffix;
+    std::string backupFile = testFile + kBackupFileSuffix;
+    CreateTestFileWithContents(testFile, "OriginalContent");
+
+    RestorableFile::RemoveAllFiles(testFile);
+
+    ASSERT_FILE_NOT_EXISTING(tmpFile);
+    ASSERT_FILE_NOT_EXISTING(testFile);
+    ASSERT_FILE_NOT_EXISTING(backupFile);
+}
+
+TEST_F(FileTest, TestRestorableFileRemoveFileAndTmpFileWithContentAndTmpFile) {
+    std::string testFile = GetTestFilePath(GetTestName());
+    std::string tmpFile = testFile + kTmpFileSuffix;
+    std::string backupFile = testFile + kBackupFileSuffix;
+    CreateTestFileWithContents(testFile, "OriginalContent");
+    CreateTestFileWithContents(testFile + kTmpFileSuffix, "TmpContent");
+
+    RestorableFile::RemoveAllFiles(testFile);
+
+    ASSERT_FILE_NOT_EXISTING(tmpFile);
+    ASSERT_FILE_NOT_EXISTING(testFile);
+    ASSERT_FILE_NOT_EXISTING(backupFile);
+}
+
+} // namespace installd
+} // namespace android
diff --git a/cmds/installd/tests/installd_file_test.xml b/cmds/installd/tests/installd_file_test.xml
new file mode 100644
index 0000000..5ec6e3f
--- /dev/null
+++ b/cmds/installd/tests/installd_file_test.xml
@@ -0,0 +1,35 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (C) 2021 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.
+-->
+<!-- Note: this is derived from the autogenerated configuration. We require
+           root support. -->
+<configuration description="Runs installd_file_test.">
+    <option name="test-suite-tag" value="apct" />
+    <option name="test-suite-tag" value="apct-native" />
+
+    <target_preparer class="com.android.tradefed.targetprep.PushFilePreparer">
+        <option name="cleanup" value="true" />
+        <option name="push"
+                value="installd_file_test->/data/local/tmp/installd_file_test" />
+    </target_preparer>
+
+    <!-- The test requires root for file access (rollback. -->
+    <target_preparer class="com.android.tradefed.targetprep.RootTargetPreparer" />
+
+    <test class="com.android.tradefed.testtype.GTest" >
+        <option name="native-test-device-path" value="/data/local/tmp" />
+        <option name="module-name" value="installd_file_test" />
+    </test>
+</configuration>