diff --git a/tests/Android.mk b/tests/Android.mk
index d8cbf1c..daec11f 100644
--- a/tests/Android.mk
+++ b/tests/Android.mk
@@ -16,12 +16,34 @@
 
 LOCAL_PATH := $(call my-dir)
 
+# libapplypatch, libapplypatch_modes, libimgdiff, libimgpatch.
+libapplypatch_static_libraries := \
+    libapplypatch_modes \
+    libapplypatch \
+    libedify \
+    libimgdiff \
+    libimgpatch \
+    libotafault \
+    libotautil \
+    libbsdiff \
+    libbspatch \
+    libdivsufsort \
+    libdivsufsort64 \
+    libutils \
+    libbase \
+    libbrotli \
+    libbz \
+    libcrypto \
+    libz \
+    libziparchive \
+
 # Unit tests
 include $(CLEAR_VARS)
 LOCAL_CFLAGS := -Wall -Werror
 LOCAL_MODULE := recovery_unit_test
 LOCAL_COMPATIBILITY_SUITE := device-tests
 LOCAL_STATIC_LIBRARIES := \
+    $(libapplypatch_static_libraries) \
     libverifier \
     librecovery_ui \
     libminui \
@@ -37,6 +59,7 @@
     libBionicGtestMain
 
 LOCAL_SRC_FILES := \
+    unit/applypatch_test.cpp \
     unit/asn1_decoder_test.cpp \
     unit/commands_test.cpp \
     unit/dirutil_test.cpp \
@@ -77,7 +100,7 @@
 LOCAL_COMPATIBILITY_SUITE := device-tests
 LOCAL_C_INCLUDES := bootable/recovery
 LOCAL_SRC_FILES := \
-    component/applypatch_test.cpp \
+    component/applypatch_modes_test.cpp \
     component/bootloader_message_test.cpp \
     component/edify_test.cpp \
     component/imgdiff_test.cpp \
@@ -92,26 +115,6 @@
 LOCAL_SHARED_LIBRARIES := \
     libhidlbase
 
-# libapplypatch, libapplypatch_modes, libimgdiff, libimgpatch.
-libapplypatch_static_libraries := \
-    libapplypatch_modes \
-    libapplypatch \
-    libedify \
-    libimgdiff \
-    libimgpatch \
-    libotafault \
-    libotautil \
-    libbsdiff \
-    libbspatch \
-    libdivsufsort \
-    libdivsufsort64 \
-    libutils \
-    libbase \
-    libbz \
-    libcrypto \
-    libz \
-    libziparchive \
-
 tune2fs_static_libraries := \
     libext2_com_err \
     libext2_blkid \
diff --git a/tests/component/applypatch_modes_test.cpp b/tests/component/applypatch_modes_test.cpp
new file mode 100644
index 0000000..b0a52b1
--- /dev/null
+++ b/tests/component/applypatch_modes_test.cpp
@@ -0,0 +1,347 @@
+/*
+ * Copyright (C) 2016 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 agree 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 <stdlib.h>
+
+#include <string>
+#include <vector>
+
+#include <android-base/file.h>
+#include <android-base/logging.h>
+#include <android-base/stringprintf.h>
+#include <android-base/test_utils.h>
+#include <bsdiff/bsdiff.h>
+#include <gtest/gtest.h>
+#include <openssl/sha.h>
+#include <zlib.h>
+
+#include "applypatch/applypatch_modes.h"
+#include "common/test_constants.h"
+#include "otautil/paths.h"
+#include "otautil/print_sha1.h"
+
+using namespace std::string_literals;
+
+// TODO(b/67849209) Remove after debug the flakiness.
+static void DecompressAndDumpRecoveryImage(const std::string& image_path) {
+  // Expected recovery_image structure
+  // chunk normal:  45066 bytes
+  // chunk deflate: 479442 bytes
+  // chunk normal:  5199 bytes
+  std::string recovery_content;
+  ASSERT_TRUE(android::base::ReadFileToString(image_path, &recovery_content));
+  ASSERT_GT(recovery_content.size(), 45066 + 5199);
+
+  z_stream strm = {};
+  strm.avail_in = recovery_content.size() - 45066 - 5199;
+  strm.next_in =
+      const_cast<uint8_t*>(reinterpret_cast<const uint8_t*>(recovery_content.data())) + 45066;
+
+  ASSERT_EQ(Z_OK, inflateInit2(&strm, -15));
+
+  constexpr unsigned int BUFFER_SIZE = 32768;
+  std::vector<uint8_t> uncompressed_data(BUFFER_SIZE);
+  size_t uncompressed_length = 0;
+  SHA_CTX ctx;
+  SHA1_Init(&ctx);
+  int ret;
+  do {
+    strm.avail_out = BUFFER_SIZE;
+    strm.next_out = uncompressed_data.data();
+
+    ret = inflate(&strm, Z_NO_FLUSH);
+    ASSERT_GE(ret, 0);
+
+    SHA1_Update(&ctx, uncompressed_data.data(), BUFFER_SIZE - strm.avail_out);
+    uncompressed_length += BUFFER_SIZE - strm.avail_out;
+  } while (ret != Z_STREAM_END);
+  inflateEnd(&strm);
+
+  uint8_t digest[SHA_DIGEST_LENGTH];
+  SHA1_Final(digest, &ctx);
+  GTEST_LOG_(INFO) << "uncompressed length " << uncompressed_length
+                   << " sha1: " << short_sha1(digest);
+}
+
+static void sha1sum(const std::string& fname, std::string* sha1, size_t* fsize = nullptr) {
+  ASSERT_TRUE(sha1 != nullptr);
+
+  std::string data;
+  ASSERT_TRUE(android::base::ReadFileToString(fname, &data));
+
+  if (fsize != nullptr) {
+    *fsize = data.size();
+  }
+
+  uint8_t digest[SHA_DIGEST_LENGTH];
+  SHA1(reinterpret_cast<const uint8_t*>(data.c_str()), data.size(), digest);
+  *sha1 = print_sha1(digest);
+}
+
+static void test_logger(android::base::LogId /* id */, android::base::LogSeverity severity,
+                        const char* /* tag */, const char* /* file */, unsigned int /* line */,
+                        const char* message) {
+  if (severity >= android::base::GetMinimumLogSeverity()) {
+    fprintf(stdout, "%s\n", message);
+  }
+}
+
+class ApplyPatchModesTest : public ::testing::Test {
+ protected:
+  void SetUp() override {
+    Paths::Get().set_cache_temp_source(cache_source.path);
+    android::base::InitLogging(nullptr, &test_logger);
+    android::base::SetMinimumLogSeverity(android::base::LogSeverity::DEBUG);
+  }
+
+  TemporaryFile cache_source;
+};
+
+TEST_F(ApplyPatchModesTest, InvalidArgs) {
+  // At least two args (including the filename).
+  ASSERT_EQ(2, applypatch_modes(1, (const char* []){ "applypatch" }));
+
+  // Unrecognized args.
+  ASSERT_EQ(2, applypatch_modes(2, (const char* []){ "applypatch", "-x" }));
+}
+
+TEST_F(ApplyPatchModesTest, PatchModeEmmcTarget) {
+  std::string boot_img = from_testdata_base("boot.img");
+  size_t boot_img_size;
+  std::string boot_img_sha1;
+  sha1sum(boot_img, &boot_img_sha1, &boot_img_size);
+
+  std::string recovery_img = from_testdata_base("recovery.img");
+  size_t recovery_img_size;
+  std::string recovery_img_sha1;
+  sha1sum(recovery_img, &recovery_img_sha1, &recovery_img_size);
+  std::string recovery_img_size_arg = std::to_string(recovery_img_size);
+
+  std::string bonus_file = from_testdata_base("bonus.file");
+
+  // applypatch -b <bonus-file> <src-file> <tgt-file> <tgt-sha1> <tgt-size> <src-sha1>:<patch>
+  std::string src_file_arg =
+      "EMMC:" + boot_img + ":" + std::to_string(boot_img_size) + ":" + boot_img_sha1;
+  TemporaryFile tgt_file;
+  std::string tgt_file_arg = "EMMC:"s + tgt_file.path;
+  std::string patch_arg = boot_img_sha1 + ":" + from_testdata_base("recovery-from-boot.p");
+  std::vector<const char*> args = { "applypatch",
+                                    "-b",
+                                    bonus_file.c_str(),
+                                    src_file_arg.c_str(),
+                                    tgt_file_arg.c_str(),
+                                    recovery_img_sha1.c_str(),
+                                    recovery_img_size_arg.c_str(),
+                                    patch_arg.c_str() };
+  ASSERT_EQ(0, applypatch_modes(args.size(), args.data()));
+}
+
+// Tests patching the EMMC target without a separate bonus file (i.e. recovery-from-boot patch has
+// everything).
+TEST_F(ApplyPatchModesTest, PatchModeEmmcTargetWithoutBonusFile) {
+  std::string boot_img = from_testdata_base("boot.img");
+  size_t boot_img_size;
+  std::string boot_img_sha1;
+  sha1sum(boot_img, &boot_img_sha1, &boot_img_size);
+
+  std::string recovery_img = from_testdata_base("recovery.img");
+  size_t recovery_img_size;
+  std::string recovery_img_sha1;
+  sha1sum(recovery_img, &recovery_img_sha1, &recovery_img_size);
+  std::string recovery_img_size_arg = std::to_string(recovery_img_size);
+
+  // applypatch <src-file> <tgt-file> <tgt-sha1> <tgt-size> <src-sha1>:<patch>
+  std::string src_file_arg =
+      "EMMC:" + boot_img + ":" + std::to_string(boot_img_size) + ":" + boot_img_sha1;
+  TemporaryFile tgt_file;
+  std::string tgt_file_arg = "EMMC:"s + tgt_file.path;
+  std::string patch_arg =
+      boot_img_sha1 + ":" + from_testdata_base("recovery-from-boot-with-bonus.p");
+  std::vector<const char*> args = { "applypatch",
+                                    src_file_arg.c_str(),
+                                    tgt_file_arg.c_str(),
+                                    recovery_img_sha1.c_str(),
+                                    recovery_img_size_arg.c_str(),
+                                    patch_arg.c_str() };
+
+  if (applypatch_modes(args.size(), args.data()) != 0) {
+    DecompressAndDumpRecoveryImage(tgt_file.path);
+    FAIL();
+  }
+}
+
+TEST_F(ApplyPatchModesTest, PatchModeEmmcTargetWithMultiplePatches) {
+  std::string boot_img = from_testdata_base("boot.img");
+  size_t boot_img_size;
+  std::string boot_img_sha1;
+  sha1sum(boot_img, &boot_img_sha1, &boot_img_size);
+
+  std::string recovery_img = from_testdata_base("recovery.img");
+  size_t recovery_img_size;
+  std::string recovery_img_sha1;
+  sha1sum(recovery_img, &recovery_img_sha1, &recovery_img_size);
+  std::string recovery_img_size_arg = std::to_string(recovery_img_size);
+
+  std::string bonus_file = from_testdata_base("bonus.file");
+
+  // applypatch -b <bonus-file> <src-file> <tgt-file> <tgt-sha1> <tgt-size> \
+  //            <src-sha1-fake1>:<patch1> <src-sha1>:<patch2> <src-sha1-fake2>:<patch3>
+  std::string src_file_arg =
+      "EMMC:" + boot_img + ":" + std::to_string(boot_img_size) + ":" + boot_img_sha1;
+  TemporaryFile tgt_file;
+  std::string tgt_file_arg = "EMMC:"s + tgt_file.path;
+  std::string bad_sha1_a = android::base::StringPrintf("%040x", rand());
+  std::string bad_sha1_b = android::base::StringPrintf("%040x", rand());
+  std::string patch1 = bad_sha1_a + ":" + from_testdata_base("recovery-from-boot.p");
+  std::string patch2 = boot_img_sha1 + ":" + from_testdata_base("recovery-from-boot.p");
+  std::string patch3 = bad_sha1_b + ":" + from_testdata_base("recovery-from-boot.p");
+  std::vector<const char*> args = { "applypatch",
+                                    "-b",
+                                    bonus_file.c_str(),
+                                    src_file_arg.c_str(),
+                                    tgt_file_arg.c_str(),
+                                    recovery_img_sha1.c_str(),
+                                    recovery_img_size_arg.c_str(),
+                                    patch1.c_str(),
+                                    patch2.c_str(),
+                                    patch3.c_str() };
+  // TODO(b/67849209): Remove after addressing the flakiness.
+  printf("Calling applypatch_modes with the following args:\n");
+  for (const auto& arg : args) {
+    printf("  %s\n", arg);
+  }
+
+  if (applypatch_modes(args.size(), args.data()) != 0) {
+    DecompressAndDumpRecoveryImage(tgt_file.path);
+    FAIL();
+  }
+}
+
+// Ensures that applypatch works with a bsdiff based recovery-from-boot.p.
+TEST_F(ApplyPatchModesTest, PatchModeEmmcTargetWithBsdiffPatch) {
+  std::string boot_img_file = from_testdata_base("boot.img");
+  std::string boot_img_sha1;
+  size_t boot_img_size;
+  sha1sum(boot_img_file, &boot_img_sha1, &boot_img_size);
+
+  std::string recovery_img_file = from_testdata_base("recovery.img");
+  std::string recovery_img_sha1;
+  size_t recovery_img_size;
+  sha1sum(recovery_img_file, &recovery_img_sha1, &recovery_img_size);
+
+  // Generate the bsdiff patch of recovery-from-boot.p.
+  std::string src_content;
+  ASSERT_TRUE(android::base::ReadFileToString(boot_img_file, &src_content));
+
+  std::string tgt_content;
+  ASSERT_TRUE(android::base::ReadFileToString(recovery_img_file, &tgt_content));
+
+  TemporaryFile patch_file;
+  ASSERT_EQ(0,
+            bsdiff::bsdiff(reinterpret_cast<const uint8_t*>(src_content.data()), src_content.size(),
+                           reinterpret_cast<const uint8_t*>(tgt_content.data()), tgt_content.size(),
+                           patch_file.path, nullptr));
+
+  // applypatch <src-file> <tgt-file> <tgt-sha1> <tgt-size> <src-sha1>:<patch>
+  std::string src_file_arg =
+      "EMMC:" + boot_img_file + ":" + std::to_string(boot_img_size) + ":" + boot_img_sha1;
+  TemporaryFile tgt_file;
+  std::string tgt_file_arg = "EMMC:"s + tgt_file.path;
+  std::string recovery_img_size_arg = std::to_string(recovery_img_size);
+  std::string patch_arg = boot_img_sha1 + ":" + patch_file.path;
+  std::vector<const char*> args = { "applypatch",
+                                    src_file_arg.c_str(),
+                                    tgt_file_arg.c_str(),
+                                    recovery_img_sha1.c_str(),
+                                    recovery_img_size_arg.c_str(),
+                                    patch_arg.c_str() };
+  ASSERT_EQ(0, applypatch_modes(args.size(), args.data()));
+
+  // Double check the patched recovery image.
+  std::string tgt_file_sha1;
+  size_t tgt_file_size;
+  sha1sum(tgt_file.path, &tgt_file_sha1, &tgt_file_size);
+  ASSERT_EQ(recovery_img_size, tgt_file_size);
+  ASSERT_EQ(recovery_img_sha1, tgt_file_sha1);
+}
+
+TEST_F(ApplyPatchModesTest, PatchModeInvalidArgs) {
+  // Invalid bonus file.
+  ASSERT_NE(0, applypatch_modes(3, (const char* []){ "applypatch", "-b", "/doesntexist" }));
+
+  std::string bonus_file = from_testdata_base("bonus.file");
+  // With bonus file, but missing args.
+  ASSERT_EQ(2, applypatch_modes(3, (const char* []){ "applypatch", "-b", bonus_file.c_str() }));
+
+  std::string boot_img = from_testdata_base("boot.img");
+  size_t boot_img_size;
+  std::string boot_img_sha1;
+  sha1sum(boot_img, &boot_img_sha1, &boot_img_size);
+
+  std::string recovery_img = from_testdata_base("recovery.img");
+  size_t size;
+  std::string recovery_img_sha1;
+  sha1sum(recovery_img, &recovery_img_sha1, &size);
+  std::string recovery_img_size = std::to_string(size);
+
+  // Bonus file is not supported in flash mode.
+  // applypatch -b <bonus-file> <src-file> <tgt-file> <tgt-sha1> <tgt-size>
+  TemporaryFile tmp4;
+  std::vector<const char*> args4 = {
+    "applypatch",
+    "-b",
+    bonus_file.c_str(),
+    boot_img.c_str(),
+    tmp4.path,
+    recovery_img_sha1.c_str(),
+    recovery_img_size.c_str(),
+  };
+  ASSERT_NE(0, applypatch_modes(args4.size(), args4.data()));
+
+  // Failed to parse patch args.
+  TemporaryFile tmp5;
+  std::string bad_arg1 =
+      "invalid-sha1:filename" + from_testdata_base("recovery-from-boot-with-bonus.p");
+  std::vector<const char*> args5 = {
+    "applypatch",
+    boot_img.c_str(),
+    tmp5.path,
+    recovery_img_sha1.c_str(),
+    recovery_img_size.c_str(),
+    bad_arg1.c_str(),
+  };
+  ASSERT_NE(0, applypatch_modes(args5.size(), args5.data()));
+
+  // Target size cannot be zero.
+  TemporaryFile tmp6;
+  std::string patch = boot_img_sha1 + ":" + from_testdata_base("recovery-from-boot-with-bonus.p");
+  std::vector<const char*> args6 = {
+    "applypatch",  boot_img.c_str(), tmp6.path, recovery_img_sha1.c_str(),
+    "0",  // target size
+    patch.c_str(),
+  };
+  ASSERT_NE(0, applypatch_modes(args6.size(), args6.data()));
+}
+
+TEST_F(ApplyPatchModesTest, CheckModeInvalidArgs) {
+  // Insufficient args.
+  ASSERT_EQ(2, applypatch_modes(2, (const char* []){ "applypatch", "-c" }));
+}
+
+TEST_F(ApplyPatchModesTest, ShowLicenses) {
+  ASSERT_EQ(0, applypatch_modes(2, (const char* []){ "applypatch", "-l" }));
+}
diff --git a/tests/component/applypatch_test.cpp b/tests/component/applypatch_test.cpp
deleted file mode 100644
index 4e44309..0000000
--- a/tests/component/applypatch_test.cpp
+++ /dev/null
@@ -1,611 +0,0 @@
-/*
- * Copyright (C) 2016 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 agree 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 <dirent.h>
-#include <fcntl.h>
-#include <libgen.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <sys/stat.h>
-#include <sys/statvfs.h>
-#include <sys/types.h>
-#include <time.h>
-
-#include <algorithm>
-#include <memory>
-#include <string>
-#include <vector>
-
-#include <android-base/file.h>
-#include <android-base/logging.h>
-#include <android-base/stringprintf.h>
-#include <android-base/test_utils.h>
-#include <android-base/unique_fd.h>
-#include <bsdiff/bsdiff.h>
-#include <gtest/gtest.h>
-#include <openssl/sha.h>
-#include <zlib.h>
-
-#include "applypatch/applypatch.h"
-#include "applypatch/applypatch_modes.h"
-#include "common/test_constants.h"
-#include "otautil/paths.h"
-#include "otautil/print_sha1.h"
-
-using namespace std::string_literals;
-
-// TODO(b/67849209) Remove after debug the flakiness.
-static void DecompressAndDumpRecoveryImage(const std::string& image_path) {
-  // Expected recovery_image structure
-  // chunk normal:  45066 bytes
-  // chunk deflate: 479442 bytes
-  // chunk normal:  5199 bytes
-  std::string recovery_content;
-  ASSERT_TRUE(android::base::ReadFileToString(image_path, &recovery_content));
-  ASSERT_GT(recovery_content.size(), 45066 + 5199);
-
-  z_stream strm = {};
-  strm.avail_in = recovery_content.size() - 45066 - 5199;
-  strm.next_in =
-      const_cast<uint8_t*>(reinterpret_cast<const uint8_t*>(recovery_content.data())) + 45066;
-
-  ASSERT_EQ(Z_OK, inflateInit2(&strm, -15));
-
-  constexpr unsigned int BUFFER_SIZE = 32768;
-  std::vector<uint8_t> uncompressed_data(BUFFER_SIZE);
-  size_t uncompressed_length = 0;
-  SHA_CTX ctx;
-  SHA1_Init(&ctx);
-  int ret;
-  do {
-    strm.avail_out = BUFFER_SIZE;
-    strm.next_out = uncompressed_data.data();
-
-    ret = inflate(&strm, Z_NO_FLUSH);
-    ASSERT_GE(ret, 0);
-
-    SHA1_Update(&ctx, uncompressed_data.data(), BUFFER_SIZE - strm.avail_out);
-    uncompressed_length += BUFFER_SIZE - strm.avail_out;
-  } while (ret != Z_STREAM_END);
-  inflateEnd(&strm);
-
-  uint8_t digest[SHA_DIGEST_LENGTH];
-  SHA1_Final(digest, &ctx);
-  GTEST_LOG_(INFO) << "uncompressed length " << uncompressed_length
-                   << " sha1: " << short_sha1(digest);
-}
-
-static void sha1sum(const std::string& fname, std::string* sha1, size_t* fsize = nullptr) {
-  ASSERT_TRUE(sha1 != nullptr);
-
-  std::string data;
-  ASSERT_TRUE(android::base::ReadFileToString(fname, &data));
-
-  if (fsize != nullptr) {
-    *fsize = data.size();
-  }
-
-  uint8_t digest[SHA_DIGEST_LENGTH];
-  SHA1(reinterpret_cast<const uint8_t*>(data.c_str()), data.size(), digest);
-  *sha1 = print_sha1(digest);
-}
-
-static void mangle_file(const std::string& fname) {
-  std::string content(1024, '\0');
-  for (size_t i = 0; i < 1024; i++) {
-    content[i] = rand() % 256;
-  }
-  ASSERT_TRUE(android::base::WriteStringToFile(content, fname));
-}
-
-static void test_logger(android::base::LogId /* id */, android::base::LogSeverity severity,
-                        const char* /* tag */, const char* /* file */, unsigned int /* line */,
-                        const char* message) {
-  if (severity >= android::base::GetMinimumLogSeverity()) {
-    fprintf(stdout, "%s\n", message);
-  }
-}
-
-class ApplyPatchTest : public ::testing::Test {
- public:
-  virtual void SetUp() override {
-    // set up files
-    old_file = from_testdata_base("old.file");
-    new_file = from_testdata_base("new.file");
-    nonexistent_file = from_testdata_base("nonexistent.file");
-
-    // set up SHA constants
-    sha1sum(old_file, &old_sha1, &old_size);
-    sha1sum(new_file, &new_sha1, &new_size);
-    srand(time(nullptr));
-    bad_sha1_a = android::base::StringPrintf("%040x", rand());
-    bad_sha1_b = android::base::StringPrintf("%040x", rand());
-  }
-
-  std::string old_file;
-  std::string new_file;
-  std::string nonexistent_file;
-
-  std::string old_sha1;
-  std::string new_sha1;
-  std::string bad_sha1_a;
-  std::string bad_sha1_b;
-
-  size_t old_size;
-  size_t new_size;
-};
-
-class ApplyPatchCacheTest : public ApplyPatchTest {
- protected:
-  void SetUp() override {
-    ApplyPatchTest::SetUp();
-    Paths::Get().set_cache_temp_source(old_file);
-  }
-};
-
-class ApplyPatchModesTest : public ::testing::Test {
- protected:
-  void SetUp() override {
-    Paths::Get().set_cache_temp_source(cache_source.path);
-    android::base::InitLogging(nullptr, &test_logger);
-    android::base::SetMinimumLogSeverity(android::base::LogSeverity::DEBUG);
-  }
-
-  TemporaryFile cache_source;
-};
-
-class FreeCacheTest : public ::testing::Test {
- protected:
-  static constexpr size_t PARTITION_SIZE = 4096 * 10;
-
-  // Returns a sorted list of files in |dirname|.
-  static std::vector<std::string> FindFilesInDir(const std::string& dirname) {
-    std::vector<std::string> file_list;
-
-    std::unique_ptr<DIR, decltype(&closedir)> d(opendir(dirname.c_str()), closedir);
-    struct dirent* de;
-    while ((de = readdir(d.get())) != 0) {
-      std::string path = dirname + "/" + de->d_name;
-
-      struct stat st;
-      if (stat(path.c_str(), &st) == 0 && S_ISREG(st.st_mode)) {
-        file_list.emplace_back(de->d_name);
-      }
-    }
-
-    std::sort(file_list.begin(), file_list.end());
-    return file_list;
-  }
-
-  static void AddFilesToDir(const std::string& dir, const std::vector<std::string>& files) {
-    std::string zeros(4096, 0);
-    for (const auto& file : files) {
-      std::string path = dir + "/" + file;
-      ASSERT_TRUE(android::base::WriteStringToFile(zeros, path));
-    }
-  }
-
-  void SetUp() override {
-    Paths::Get().set_cache_log_directory(mock_log_dir.path);
-  }
-
-  // A mock method to calculate the free space. It assumes the partition has a total size of 40960
-  // bytes and all files are 4096 bytes in size.
-  size_t MockFreeSpaceChecker(const std::string& dirname) {
-    std::vector<std::string> files = FindFilesInDir(dirname);
-    return PARTITION_SIZE - 4096 * files.size();
-  }
-
-  TemporaryDir mock_cache;
-  TemporaryDir mock_log_dir;
-};
-
-TEST_F(ApplyPatchTest, CheckModeSkip) {
-  std::vector<std::string> sha1s;
-  ASSERT_EQ(0, applypatch_check(&old_file[0], sha1s));
-}
-
-TEST_F(ApplyPatchTest, CheckModeSingle) {
-  std::vector<std::string> sha1s = { old_sha1 };
-  ASSERT_EQ(0, applypatch_check(&old_file[0], sha1s));
-}
-
-TEST_F(ApplyPatchTest, CheckModeMultiple) {
-  std::vector<std::string> sha1s = { bad_sha1_a, old_sha1, bad_sha1_b };
-  ASSERT_EQ(0, applypatch_check(&old_file[0], sha1s));
-}
-
-TEST_F(ApplyPatchTest, CheckModeFailure) {
-  std::vector<std::string> sha1s = { bad_sha1_a, bad_sha1_b };
-  ASSERT_NE(0, applypatch_check(&old_file[0], sha1s));
-}
-
-TEST_F(ApplyPatchTest, CheckModeEmmcTarget) {
-  // EMMC:old_file:size:sha1 should pass the check.
-  std::string src_file =
-      "EMMC:" + old_file + ":" + std::to_string(old_size) + ":" + old_sha1;
-  std::vector<std::string> sha1s;
-  ASSERT_EQ(0, applypatch_check(src_file.c_str(), sha1s));
-
-  // EMMC:old_file:(size-1):sha1:(size+1):sha1 should fail the check.
-  src_file = "EMMC:" + old_file + ":" + std::to_string(old_size - 1) + ":" + old_sha1 + ":" +
-             std::to_string(old_size + 1) + ":" + old_sha1;
-  ASSERT_EQ(1, applypatch_check(src_file.c_str(), sha1s));
-
-  // EMMC:old_file:(size-1):sha1:size:sha1:(size+1):sha1 should pass the check.
-  src_file = "EMMC:" + old_file + ":" +
-             std::to_string(old_size - 1) + ":" + old_sha1 + ":" +
-             std::to_string(old_size) + ":" + old_sha1 + ":" +
-             std::to_string(old_size + 1) + ":" + old_sha1;
-  ASSERT_EQ(0, applypatch_check(src_file.c_str(), sha1s));
-
-  // EMMC:old_file:(size+1):sha1:(size-1):sha1:size:sha1 should pass the check.
-  src_file = "EMMC:" + old_file + ":" +
-             std::to_string(old_size + 1) + ":" + old_sha1 + ":" +
-             std::to_string(old_size - 1) + ":" + old_sha1 + ":" +
-             std::to_string(old_size) + ":" + old_sha1;
-  ASSERT_EQ(0, applypatch_check(src_file.c_str(), sha1s));
-
-  // EMMC:new_file:(size+1):old_sha1:(size-1):old_sha1:size:old_sha1:size:new_sha1
-  // should pass the check.
-  src_file = "EMMC:" + new_file + ":" +
-             std::to_string(old_size + 1) + ":" + old_sha1 + ":" +
-             std::to_string(old_size - 1) + ":" + old_sha1 + ":" +
-             std::to_string(old_size) + ":" + old_sha1 + ":" +
-             std::to_string(new_size) + ":" + new_sha1;
-  ASSERT_EQ(0, applypatch_check(src_file.c_str(), sha1s));
-}
-
-TEST_F(ApplyPatchCacheTest, CheckCacheCorruptedSourceSingle) {
-  TemporaryFile temp_file;
-  mangle_file(temp_file.path);
-  std::vector<std::string> sha1s_single = { old_sha1 };
-  ASSERT_EQ(0, applypatch_check(temp_file.path, sha1s_single));
-  ASSERT_EQ(0, applypatch_check(nonexistent_file.c_str(), sha1s_single));
-}
-
-TEST_F(ApplyPatchCacheTest, CheckCacheCorruptedSourceMultiple) {
-  TemporaryFile temp_file;
-  mangle_file(temp_file.path);
-  std::vector<std::string> sha1s_multiple = { bad_sha1_a, old_sha1, bad_sha1_b };
-  ASSERT_EQ(0, applypatch_check(temp_file.path, sha1s_multiple));
-  ASSERT_EQ(0, applypatch_check(nonexistent_file.c_str(), sha1s_multiple));
-}
-
-TEST_F(ApplyPatchCacheTest, CheckCacheCorruptedSourceFailure) {
-  TemporaryFile temp_file;
-  mangle_file(temp_file.path);
-  std::vector<std::string> sha1s_failure = { bad_sha1_a, bad_sha1_b };
-  ASSERT_NE(0, applypatch_check(temp_file.path, sha1s_failure));
-  ASSERT_NE(0, applypatch_check(nonexistent_file.c_str(), sha1s_failure));
-}
-
-TEST_F(ApplyPatchModesTest, InvalidArgs) {
-  // At least two args (including the filename).
-  ASSERT_EQ(2, applypatch_modes(1, (const char* []){ "applypatch" }));
-
-  // Unrecognized args.
-  ASSERT_EQ(2, applypatch_modes(2, (const char* []){ "applypatch", "-x" }));
-}
-
-TEST_F(ApplyPatchModesTest, PatchModeEmmcTarget) {
-  std::string boot_img = from_testdata_base("boot.img");
-  size_t boot_img_size;
-  std::string boot_img_sha1;
-  sha1sum(boot_img, &boot_img_sha1, &boot_img_size);
-
-  std::string recovery_img = from_testdata_base("recovery.img");
-  size_t recovery_img_size;
-  std::string recovery_img_sha1;
-  sha1sum(recovery_img, &recovery_img_sha1, &recovery_img_size);
-  std::string recovery_img_size_arg = std::to_string(recovery_img_size);
-
-  std::string bonus_file = from_testdata_base("bonus.file");
-
-  // applypatch -b <bonus-file> <src-file> <tgt-file> <tgt-sha1> <tgt-size> <src-sha1>:<patch>
-  std::string src_file_arg =
-      "EMMC:" + boot_img + ":" + std::to_string(boot_img_size) + ":" + boot_img_sha1;
-  TemporaryFile tgt_file;
-  std::string tgt_file_arg = "EMMC:"s + tgt_file.path;
-  std::string patch_arg = boot_img_sha1 + ":" + from_testdata_base("recovery-from-boot.p");
-  std::vector<const char*> args = { "applypatch",
-                                    "-b",
-                                    bonus_file.c_str(),
-                                    src_file_arg.c_str(),
-                                    tgt_file_arg.c_str(),
-                                    recovery_img_sha1.c_str(),
-                                    recovery_img_size_arg.c_str(),
-                                    patch_arg.c_str() };
-  ASSERT_EQ(0, applypatch_modes(args.size(), args.data()));
-}
-
-// Tests patching the EMMC target without a separate bonus file (i.e. recovery-from-boot patch has
-// everything).
-TEST_F(ApplyPatchModesTest, PatchModeEmmcTargetWithoutBonusFile) {
-  std::string boot_img = from_testdata_base("boot.img");
-  size_t boot_img_size;
-  std::string boot_img_sha1;
-  sha1sum(boot_img, &boot_img_sha1, &boot_img_size);
-
-  std::string recovery_img = from_testdata_base("recovery.img");
-  size_t recovery_img_size;
-  std::string recovery_img_sha1;
-  sha1sum(recovery_img, &recovery_img_sha1, &recovery_img_size);
-  std::string recovery_img_size_arg = std::to_string(recovery_img_size);
-
-  // applypatch <src-file> <tgt-file> <tgt-sha1> <tgt-size> <src-sha1>:<patch>
-  std::string src_file_arg =
-      "EMMC:" + boot_img + ":" + std::to_string(boot_img_size) + ":" + boot_img_sha1;
-  TemporaryFile tgt_file;
-  std::string tgt_file_arg = "EMMC:"s + tgt_file.path;
-  std::string patch_arg =
-      boot_img_sha1 + ":" + from_testdata_base("recovery-from-boot-with-bonus.p");
-  std::vector<const char*> args = { "applypatch",
-                                    src_file_arg.c_str(),
-                                    tgt_file_arg.c_str(),
-                                    recovery_img_sha1.c_str(),
-                                    recovery_img_size_arg.c_str(),
-                                    patch_arg.c_str() };
-
-  if (applypatch_modes(args.size(), args.data()) != 0) {
-    DecompressAndDumpRecoveryImage(tgt_file.path);
-    FAIL();
-  }
-}
-
-TEST_F(ApplyPatchModesTest, PatchModeEmmcTargetWithMultiplePatches) {
-  std::string boot_img = from_testdata_base("boot.img");
-  size_t boot_img_size;
-  std::string boot_img_sha1;
-  sha1sum(boot_img, &boot_img_sha1, &boot_img_size);
-
-  std::string recovery_img = from_testdata_base("recovery.img");
-  size_t recovery_img_size;
-  std::string recovery_img_sha1;
-  sha1sum(recovery_img, &recovery_img_sha1, &recovery_img_size);
-  std::string recovery_img_size_arg = std::to_string(recovery_img_size);
-
-  std::string bonus_file = from_testdata_base("bonus.file");
-
-  // applypatch -b <bonus-file> <src-file> <tgt-file> <tgt-sha1> <tgt-size> \
-  //            <src-sha1-fake1>:<patch1> <src-sha1>:<patch2> <src-sha1-fake2>:<patch3>
-  std::string src_file_arg =
-      "EMMC:" + boot_img + ":" + std::to_string(boot_img_size) + ":" + boot_img_sha1;
-  TemporaryFile tgt_file;
-  std::string tgt_file_arg = "EMMC:"s + tgt_file.path;
-  std::string bad_sha1_a = android::base::StringPrintf("%040x", rand());
-  std::string bad_sha1_b = android::base::StringPrintf("%040x", rand());
-  std::string patch1 = bad_sha1_a + ":" + from_testdata_base("recovery-from-boot.p");
-  std::string patch2 = boot_img_sha1 + ":" + from_testdata_base("recovery-from-boot.p");
-  std::string patch3 = bad_sha1_b + ":" + from_testdata_base("recovery-from-boot.p");
-  std::vector<const char*> args = { "applypatch",
-                                    "-b",
-                                    bonus_file.c_str(),
-                                    src_file_arg.c_str(),
-                                    tgt_file_arg.c_str(),
-                                    recovery_img_sha1.c_str(),
-                                    recovery_img_size_arg.c_str(),
-                                    patch1.c_str(),
-                                    patch2.c_str(),
-                                    patch3.c_str() };
-  // TODO(b/67849209): Remove after addressing the flakiness.
-  printf("Calling applypatch_modes with the following args:\n");
-  for (const auto& arg : args) {
-    printf("  %s\n", arg);
-  }
-
-  if (applypatch_modes(args.size(), args.data()) != 0) {
-    DecompressAndDumpRecoveryImage(tgt_file.path);
-    FAIL();
-  }
-}
-
-// Ensures that applypatch works with a bsdiff based recovery-from-boot.p.
-TEST_F(ApplyPatchModesTest, PatchModeEmmcTargetWithBsdiffPatch) {
-  std::string boot_img_file = from_testdata_base("boot.img");
-  std::string boot_img_sha1;
-  size_t boot_img_size;
-  sha1sum(boot_img_file, &boot_img_sha1, &boot_img_size);
-
-  std::string recovery_img_file = from_testdata_base("recovery.img");
-  std::string recovery_img_sha1;
-  size_t recovery_img_size;
-  sha1sum(recovery_img_file, &recovery_img_sha1, &recovery_img_size);
-
-  // Generate the bsdiff patch of recovery-from-boot.p.
-  std::string src_content;
-  ASSERT_TRUE(android::base::ReadFileToString(boot_img_file, &src_content));
-
-  std::string tgt_content;
-  ASSERT_TRUE(android::base::ReadFileToString(recovery_img_file, &tgt_content));
-
-  TemporaryFile patch_file;
-  ASSERT_EQ(0,
-            bsdiff::bsdiff(reinterpret_cast<const uint8_t*>(src_content.data()), src_content.size(),
-                           reinterpret_cast<const uint8_t*>(tgt_content.data()), tgt_content.size(),
-                           patch_file.path, nullptr));
-
-  // applypatch <src-file> <tgt-file> <tgt-sha1> <tgt-size> <src-sha1>:<patch>
-  std::string src_file_arg =
-      "EMMC:" + boot_img_file + ":" + std::to_string(boot_img_size) + ":" + boot_img_sha1;
-  TemporaryFile tgt_file;
-  std::string tgt_file_arg = "EMMC:"s + tgt_file.path;
-  std::string recovery_img_size_arg = std::to_string(recovery_img_size);
-  std::string patch_arg = boot_img_sha1 + ":" + patch_file.path;
-  std::vector<const char*> args = { "applypatch",
-                                    src_file_arg.c_str(),
-                                    tgt_file_arg.c_str(),
-                                    recovery_img_sha1.c_str(),
-                                    recovery_img_size_arg.c_str(),
-                                    patch_arg.c_str() };
-  ASSERT_EQ(0, applypatch_modes(args.size(), args.data()));
-
-  // Double check the patched recovery image.
-  std::string tgt_file_sha1;
-  size_t tgt_file_size;
-  sha1sum(tgt_file.path, &tgt_file_sha1, &tgt_file_size);
-  ASSERT_EQ(recovery_img_size, tgt_file_size);
-  ASSERT_EQ(recovery_img_sha1, tgt_file_sha1);
-}
-
-TEST_F(ApplyPatchModesTest, PatchModeInvalidArgs) {
-  // Invalid bonus file.
-  ASSERT_NE(0, applypatch_modes(3, (const char* []){ "applypatch", "-b", "/doesntexist" }));
-
-  std::string bonus_file = from_testdata_base("bonus.file");
-  // With bonus file, but missing args.
-  ASSERT_EQ(2, applypatch_modes(3, (const char* []){ "applypatch", "-b", bonus_file.c_str() }));
-
-  std::string boot_img = from_testdata_base("boot.img");
-  size_t boot_img_size;
-  std::string boot_img_sha1;
-  sha1sum(boot_img, &boot_img_sha1, &boot_img_size);
-
-  std::string recovery_img = from_testdata_base("recovery.img");
-  size_t size;
-  std::string recovery_img_sha1;
-  sha1sum(recovery_img, &recovery_img_sha1, &size);
-  std::string recovery_img_size = std::to_string(size);
-
-  // Bonus file is not supported in flash mode.
-  // applypatch -b <bonus-file> <src-file> <tgt-file> <tgt-sha1> <tgt-size>
-  TemporaryFile tmp4;
-  std::vector<const char*> args4 = {
-    "applypatch",
-    "-b",
-    bonus_file.c_str(),
-    boot_img.c_str(),
-    tmp4.path,
-    recovery_img_sha1.c_str(),
-    recovery_img_size.c_str()
-  };
-  ASSERT_NE(0, applypatch_modes(args4.size(), args4.data()));
-
-  // Failed to parse patch args.
-  TemporaryFile tmp5;
-  std::string bad_arg1 =
-      "invalid-sha1:filename" + from_testdata_base("recovery-from-boot-with-bonus.p");
-  std::vector<const char*> args5 = {
-    "applypatch",
-    boot_img.c_str(),
-    tmp5.path,
-    recovery_img_sha1.c_str(),
-    recovery_img_size.c_str(),
-    bad_arg1.c_str()
-  };
-  ASSERT_NE(0, applypatch_modes(args5.size(), args5.data()));
-
-  // Target size cannot be zero.
-  TemporaryFile tmp6;
-  std::string patch = boot_img_sha1 + ":" + from_testdata_base("recovery-from-boot-with-bonus.p");
-  std::vector<const char*> args6 = {
-    "applypatch",
-    boot_img.c_str(),
-    tmp6.path,
-    recovery_img_sha1.c_str(),
-    "0",  // target size
-    patch.c_str()
-  };
-  ASSERT_NE(0, applypatch_modes(args6.size(), args6.data()));
-}
-
-TEST_F(ApplyPatchModesTest, CheckModeInvalidArgs) {
-  // Insufficient args.
-  ASSERT_EQ(2, applypatch_modes(2, (const char* []){ "applypatch", "-c" }));
-}
-
-TEST_F(ApplyPatchModesTest, ShowLicenses) {
-  ASSERT_EQ(0, applypatch_modes(2, (const char* []){ "applypatch", "-l" }));
-}
-
-TEST_F(FreeCacheTest, FreeCacheSmoke) {
-  std::vector<std::string> files = { "file1", "file2", "file3" };
-  AddFilesToDir(mock_cache.path, files);
-  ASSERT_EQ(files, FindFilesInDir(mock_cache.path));
-  ASSERT_EQ(4096 * 7, MockFreeSpaceChecker(mock_cache.path));
-
-  ASSERT_TRUE(RemoveFilesInDirectory(4096 * 9, mock_cache.path, [&](const std::string& dir) {
-    return this->MockFreeSpaceChecker(dir);
-  }));
-
-  ASSERT_EQ(std::vector<std::string>{ "file3" }, FindFilesInDir(mock_cache.path));
-  ASSERT_EQ(4096 * 9, MockFreeSpaceChecker(mock_cache.path));
-}
-
-TEST_F(FreeCacheTest, FreeCacheOpenFile) {
-  std::vector<std::string> files = { "file1", "file2" };
-  AddFilesToDir(mock_cache.path, files);
-  ASSERT_EQ(files, FindFilesInDir(mock_cache.path));
-  ASSERT_EQ(4096 * 8, MockFreeSpaceChecker(mock_cache.path));
-
-  std::string file1_path = mock_cache.path + "/file1"s;
-  android::base::unique_fd fd(open(file1_path.c_str(), O_RDONLY));
-
-  // file1 can't be deleted as it's opened by us.
-  ASSERT_FALSE(RemoveFilesInDirectory(4096 * 10, mock_cache.path, [&](const std::string& dir) {
-    return this->MockFreeSpaceChecker(dir);
-  }));
-
-  ASSERT_EQ(std::vector<std::string>{ "file1" }, FindFilesInDir(mock_cache.path));
-}
-
-TEST_F(FreeCacheTest, FreeCacheLogsSmoke) {
-  std::vector<std::string> log_files = { "last_log", "last_log.1", "last_kmsg.2", "last_log.5",
-                                         "last_log.10" };
-  AddFilesToDir(mock_log_dir.path, log_files);
-  ASSERT_EQ(4096 * 5, MockFreeSpaceChecker(mock_log_dir.path));
-
-  ASSERT_TRUE(RemoveFilesInDirectory(4096 * 8, mock_log_dir.path, [&](const std::string& dir) {
-    return this->MockFreeSpaceChecker(dir);
-  }));
-
-  // Logs with a higher index will be deleted first
-  std::vector<std::string> expected = { "last_log", "last_log.1" };
-  ASSERT_EQ(expected, FindFilesInDir(mock_log_dir.path));
-  ASSERT_EQ(4096 * 8, MockFreeSpaceChecker(mock_log_dir.path));
-}
-
-TEST_F(FreeCacheTest, FreeCacheLogsStringComparison) {
-  std::vector<std::string> log_files = { "last_log.1", "last_kmsg.1", "last_log.not_number",
-                                         "last_kmsgrandom" };
-  AddFilesToDir(mock_log_dir.path, log_files);
-  ASSERT_EQ(4096 * 6, MockFreeSpaceChecker(mock_log_dir.path));
-
-  ASSERT_TRUE(RemoveFilesInDirectory(4096 * 9, mock_log_dir.path, [&](const std::string& dir) {
-    return this->MockFreeSpaceChecker(dir);
-  }));
-
-  // Logs with incorrect format will be deleted first; and the last_kmsg with the same index is
-  // deleted before last_log.
-  std::vector<std::string> expected = { "last_log.1" };
-  ASSERT_EQ(expected, FindFilesInDir(mock_log_dir.path));
-  ASSERT_EQ(4096 * 9, MockFreeSpaceChecker(mock_log_dir.path));
-}
-
-TEST_F(FreeCacheTest, FreeCacheLogsOtherFiles) {
-  std::vector<std::string> log_files = { "last_install", "command", "block.map", "last_log",
-                                         "last_kmsg.1" };
-  AddFilesToDir(mock_log_dir.path, log_files);
-  ASSERT_EQ(4096 * 5, MockFreeSpaceChecker(mock_log_dir.path));
-
-  ASSERT_FALSE(RemoveFilesInDirectory(4096 * 8, mock_log_dir.path, [&](const std::string& dir) {
-    return this->MockFreeSpaceChecker(dir);
-  }));
-
-  // Non log files in /cache/recovery won't be deleted.
-  std::vector<std::string> expected = { "block.map", "command", "last_install" };
-  ASSERT_EQ(expected, FindFilesInDir(mock_log_dir.path));
-}
diff --git a/tests/unit/applypatch_test.cpp b/tests/unit/applypatch_test.cpp
new file mode 100644
index 0000000..4fbdd37
--- /dev/null
+++ b/tests/unit/applypatch_test.cpp
@@ -0,0 +1,303 @@
+/*
+ * Copyright (C) 2016 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 agree 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 <dirent.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <time.h>
+#include <unistd.h>
+
+#include <algorithm>
+#include <memory>
+#include <string>
+#include <vector>
+
+#include <android-base/file.h>
+#include <android-base/stringprintf.h>
+#include <android-base/test_utils.h>
+#include <android-base/unique_fd.h>
+#include <gtest/gtest.h>
+#include <openssl/sha.h>
+
+#include "applypatch/applypatch.h"
+#include "common/test_constants.h"
+#include "otautil/paths.h"
+#include "otautil/print_sha1.h"
+
+using namespace std::string_literals;
+
+static void sha1sum(const std::string& fname, std::string* sha1, size_t* fsize = nullptr) {
+  ASSERT_TRUE(sha1 != nullptr);
+
+  std::string data;
+  ASSERT_TRUE(android::base::ReadFileToString(fname, &data));
+
+  if (fsize != nullptr) {
+    *fsize = data.size();
+  }
+
+  uint8_t digest[SHA_DIGEST_LENGTH];
+  SHA1(reinterpret_cast<const uint8_t*>(data.c_str()), data.size(), digest);
+  *sha1 = print_sha1(digest);
+}
+
+static void mangle_file(const std::string& fname) {
+  std::string content(1024, '\0');
+  for (size_t i = 0; i < 1024; i++) {
+    content[i] = rand() % 256;
+  }
+  ASSERT_TRUE(android::base::WriteStringToFile(content, fname));
+}
+
+class ApplyPatchTest : public ::testing::Test {
+ public:
+  void SetUp() override {
+    // set up files
+    old_file = from_testdata_base("old.file");
+    new_file = from_testdata_base("new.file");
+    nonexistent_file = from_testdata_base("nonexistent.file");
+
+    // set up SHA constants
+    sha1sum(old_file, &old_sha1, &old_size);
+    sha1sum(new_file, &new_sha1, &new_size);
+    srand(time(nullptr));
+    bad_sha1_a = android::base::StringPrintf("%040x", rand());
+    bad_sha1_b = android::base::StringPrintf("%040x", rand());
+  }
+
+  std::string old_file;
+  std::string new_file;
+  std::string nonexistent_file;
+
+  std::string old_sha1;
+  std::string new_sha1;
+  std::string bad_sha1_a;
+  std::string bad_sha1_b;
+
+  size_t old_size;
+  size_t new_size;
+};
+
+TEST_F(ApplyPatchTest, CheckModeSkip) {
+  std::vector<std::string> sha1s;
+  ASSERT_EQ(0, applypatch_check(&old_file[0], sha1s));
+}
+
+TEST_F(ApplyPatchTest, CheckModeSingle) {
+  std::vector<std::string> sha1s = { old_sha1 };
+  ASSERT_EQ(0, applypatch_check(&old_file[0], sha1s));
+}
+
+TEST_F(ApplyPatchTest, CheckModeMultiple) {
+  std::vector<std::string> sha1s = { bad_sha1_a, old_sha1, bad_sha1_b };
+  ASSERT_EQ(0, applypatch_check(&old_file[0], sha1s));
+}
+
+TEST_F(ApplyPatchTest, CheckModeFailure) {
+  std::vector<std::string> sha1s = { bad_sha1_a, bad_sha1_b };
+  ASSERT_NE(0, applypatch_check(&old_file[0], sha1s));
+}
+
+TEST_F(ApplyPatchTest, CheckModeEmmcTarget) {
+  // EMMC:old_file:size:sha1 should pass the check.
+  std::string src_file = "EMMC:" + old_file + ":" + std::to_string(old_size) + ":" + old_sha1;
+  std::vector<std::string> sha1s;
+  ASSERT_EQ(0, applypatch_check(src_file.c_str(), sha1s));
+
+  // EMMC:old_file:(size-1):sha1:(size+1):sha1 should fail the check.
+  src_file = "EMMC:" + old_file + ":" + std::to_string(old_size - 1) + ":" + old_sha1 + ":" +
+             std::to_string(old_size + 1) + ":" + old_sha1;
+  ASSERT_EQ(1, applypatch_check(src_file.c_str(), sha1s));
+
+  // EMMC:old_file:(size-1):sha1:size:sha1:(size+1):sha1 should pass the check.
+  src_file = "EMMC:" + old_file + ":" + std::to_string(old_size - 1) + ":" + old_sha1 + ":" +
+             std::to_string(old_size) + ":" + old_sha1 + ":" + std::to_string(old_size + 1) + ":" +
+             old_sha1;
+  ASSERT_EQ(0, applypatch_check(src_file.c_str(), sha1s));
+
+  // EMMC:old_file:(size+1):sha1:(size-1):sha1:size:sha1 should pass the check.
+  src_file = "EMMC:" + old_file + ":" + std::to_string(old_size + 1) + ":" + old_sha1 + ":" +
+             std::to_string(old_size - 1) + ":" + old_sha1 + ":" + std::to_string(old_size) + ":" +
+             old_sha1;
+  ASSERT_EQ(0, applypatch_check(src_file.c_str(), sha1s));
+
+  // EMMC:new_file:(size+1):old_sha1:(size-1):old_sha1:size:old_sha1:size:new_sha1
+  // should pass the check.
+  src_file = "EMMC:" + new_file + ":" + std::to_string(old_size + 1) + ":" + old_sha1 + ":" +
+             std::to_string(old_size - 1) + ":" + old_sha1 + ":" + std::to_string(old_size) + ":" +
+             old_sha1 + ":" + std::to_string(new_size) + ":" + new_sha1;
+  ASSERT_EQ(0, applypatch_check(src_file.c_str(), sha1s));
+}
+
+class ApplyPatchCacheTest : public ApplyPatchTest {
+ protected:
+  void SetUp() override {
+    ApplyPatchTest::SetUp();
+    Paths::Get().set_cache_temp_source(old_file);
+  }
+};
+
+TEST_F(ApplyPatchCacheTest, CheckCacheCorruptedSourceSingle) {
+  TemporaryFile temp_file;
+  mangle_file(temp_file.path);
+  std::vector<std::string> sha1s_single = { old_sha1 };
+  ASSERT_EQ(0, applypatch_check(temp_file.path, sha1s_single));
+  ASSERT_EQ(0, applypatch_check(nonexistent_file.c_str(), sha1s_single));
+}
+
+TEST_F(ApplyPatchCacheTest, CheckCacheCorruptedSourceMultiple) {
+  TemporaryFile temp_file;
+  mangle_file(temp_file.path);
+  std::vector<std::string> sha1s_multiple = { bad_sha1_a, old_sha1, bad_sha1_b };
+  ASSERT_EQ(0, applypatch_check(temp_file.path, sha1s_multiple));
+  ASSERT_EQ(0, applypatch_check(nonexistent_file.c_str(), sha1s_multiple));
+}
+
+TEST_F(ApplyPatchCacheTest, CheckCacheCorruptedSourceFailure) {
+  TemporaryFile temp_file;
+  mangle_file(temp_file.path);
+  std::vector<std::string> sha1s_failure = { bad_sha1_a, bad_sha1_b };
+  ASSERT_NE(0, applypatch_check(temp_file.path, sha1s_failure));
+  ASSERT_NE(0, applypatch_check(nonexistent_file.c_str(), sha1s_failure));
+}
+
+class FreeCacheTest : public ::testing::Test {
+ protected:
+  static constexpr size_t PARTITION_SIZE = 4096 * 10;
+
+  // Returns a sorted list of files in |dirname|.
+  static std::vector<std::string> FindFilesInDir(const std::string& dirname) {
+    std::vector<std::string> file_list;
+
+    std::unique_ptr<DIR, decltype(&closedir)> d(opendir(dirname.c_str()), closedir);
+    struct dirent* de;
+    while ((de = readdir(d.get())) != 0) {
+      std::string path = dirname + "/" + de->d_name;
+
+      struct stat st;
+      if (stat(path.c_str(), &st) == 0 && S_ISREG(st.st_mode)) {
+        file_list.emplace_back(de->d_name);
+      }
+    }
+
+    std::sort(file_list.begin(), file_list.end());
+    return file_list;
+  }
+
+  static void AddFilesToDir(const std::string& dir, const std::vector<std::string>& files) {
+    std::string zeros(4096, 0);
+    for (const auto& file : files) {
+      std::string path = dir + "/" + file;
+      ASSERT_TRUE(android::base::WriteStringToFile(zeros, path));
+    }
+  }
+
+  void SetUp() override {
+    Paths::Get().set_cache_log_directory(mock_log_dir.path);
+  }
+
+  // A mock method to calculate the free space. It assumes the partition has a total size of 40960
+  // bytes and all files are 4096 bytes in size.
+  size_t MockFreeSpaceChecker(const std::string& dirname) {
+    std::vector<std::string> files = FindFilesInDir(dirname);
+    return PARTITION_SIZE - 4096 * files.size();
+  }
+
+  TemporaryDir mock_cache;
+  TemporaryDir mock_log_dir;
+};
+
+TEST_F(FreeCacheTest, FreeCacheSmoke) {
+  std::vector<std::string> files = { "file1", "file2", "file3" };
+  AddFilesToDir(mock_cache.path, files);
+  ASSERT_EQ(files, FindFilesInDir(mock_cache.path));
+  ASSERT_EQ(4096 * 7, MockFreeSpaceChecker(mock_cache.path));
+
+  ASSERT_TRUE(RemoveFilesInDirectory(4096 * 9, mock_cache.path, [&](const std::string& dir) {
+    return this->MockFreeSpaceChecker(dir);
+  }));
+
+  ASSERT_EQ(std::vector<std::string>{ "file3" }, FindFilesInDir(mock_cache.path));
+  ASSERT_EQ(4096 * 9, MockFreeSpaceChecker(mock_cache.path));
+}
+
+TEST_F(FreeCacheTest, FreeCacheOpenFile) {
+  std::vector<std::string> files = { "file1", "file2" };
+  AddFilesToDir(mock_cache.path, files);
+  ASSERT_EQ(files, FindFilesInDir(mock_cache.path));
+  ASSERT_EQ(4096 * 8, MockFreeSpaceChecker(mock_cache.path));
+
+  std::string file1_path = mock_cache.path + "/file1"s;
+  android::base::unique_fd fd(open(file1_path.c_str(), O_RDONLY));
+
+  // file1 can't be deleted as it's opened by us.
+  ASSERT_FALSE(RemoveFilesInDirectory(4096 * 10, mock_cache.path, [&](const std::string& dir) {
+    return this->MockFreeSpaceChecker(dir);
+  }));
+
+  ASSERT_EQ(std::vector<std::string>{ "file1" }, FindFilesInDir(mock_cache.path));
+}
+
+TEST_F(FreeCacheTest, FreeCacheLogsSmoke) {
+  std::vector<std::string> log_files = { "last_log", "last_log.1", "last_kmsg.2", "last_log.5",
+                                         "last_log.10" };
+  AddFilesToDir(mock_log_dir.path, log_files);
+  ASSERT_EQ(4096 * 5, MockFreeSpaceChecker(mock_log_dir.path));
+
+  ASSERT_TRUE(RemoveFilesInDirectory(4096 * 8, mock_log_dir.path, [&](const std::string& dir) {
+    return this->MockFreeSpaceChecker(dir);
+  }));
+
+  // Logs with a higher index will be deleted first
+  std::vector<std::string> expected = { "last_log", "last_log.1" };
+  ASSERT_EQ(expected, FindFilesInDir(mock_log_dir.path));
+  ASSERT_EQ(4096 * 8, MockFreeSpaceChecker(mock_log_dir.path));
+}
+
+TEST_F(FreeCacheTest, FreeCacheLogsStringComparison) {
+  std::vector<std::string> log_files = { "last_log.1", "last_kmsg.1", "last_log.not_number",
+                                         "last_kmsgrandom" };
+  AddFilesToDir(mock_log_dir.path, log_files);
+  ASSERT_EQ(4096 * 6, MockFreeSpaceChecker(mock_log_dir.path));
+
+  ASSERT_TRUE(RemoveFilesInDirectory(4096 * 9, mock_log_dir.path, [&](const std::string& dir) {
+    return this->MockFreeSpaceChecker(dir);
+  }));
+
+  // Logs with incorrect format will be deleted first; and the last_kmsg with the same index is
+  // deleted before last_log.
+  std::vector<std::string> expected = { "last_log.1" };
+  ASSERT_EQ(expected, FindFilesInDir(mock_log_dir.path));
+  ASSERT_EQ(4096 * 9, MockFreeSpaceChecker(mock_log_dir.path));
+}
+
+TEST_F(FreeCacheTest, FreeCacheLogsOtherFiles) {
+  std::vector<std::string> log_files = { "last_install", "command", "block.map", "last_log",
+                                         "last_kmsg.1" };
+  AddFilesToDir(mock_log_dir.path, log_files);
+  ASSERT_EQ(4096 * 5, MockFreeSpaceChecker(mock_log_dir.path));
+
+  ASSERT_FALSE(RemoveFilesInDirectory(4096 * 8, mock_log_dir.path, [&](const std::string& dir) {
+    return this->MockFreeSpaceChecker(dir);
+  }));
+
+  // Non log files in /cache/recovery won't be deleted.
+  std::vector<std::string> expected = { "block.map", "command", "last_install" };
+  ASSERT_EQ(expected, FindFilesInDir(mock_log_dir.path));
+}