diff --git a/applypatch/Android.mk b/applypatch/Android.mk
index 9bbac44..fa0fe8a 100644
--- a/applypatch/Android.mk
+++ b/applypatch/Android.mk
@@ -68,21 +68,41 @@
 LOCAL_CFLAGS := -Werror
 include $(BUILD_HOST_STATIC_LIBRARY)
 
-# applypatch (executable)
+# libapplypatch_modes (static library)
 # ===============================
 include $(CLEAR_VARS)
 LOCAL_CLANG := true
-LOCAL_SRC_FILES := main.cpp
+LOCAL_SRC_FILES := \
+    applypatch_modes.cpp
+LOCAL_MODULE := libapplypatch_modes
+LOCAL_C_INCLUDES := bootable/recovery
+LOCAL_STATIC_LIBRARIES := \
+    libapplypatch \
+    libbase \
+    libedify \
+    libcrypto
+LOCAL_CFLAGS := -Werror
+include $(BUILD_STATIC_LIBRARY)
+
+# applypatch (target executable)
+# ===============================
+include $(CLEAR_VARS)
+LOCAL_CLANG := true
+LOCAL_SRC_FILES := applypatch_main.cpp
 LOCAL_MODULE := applypatch
-LOCAL_C_INCLUDES += bootable/recovery
-LOCAL_STATIC_LIBRARIES += \
+LOCAL_C_INCLUDES := bootable/recovery
+LOCAL_STATIC_LIBRARIES := \
+    libapplypatch_modes \
     libapplypatch \
     libbase \
     libedify \
     libotafault \
     libcrypto \
     libbz
-LOCAL_SHARED_LIBRARIES += libbase libz libcutils libc
+LOCAL_SHARED_LIBRARIES := \
+    libbase \
+    libz \
+    libcutils
 LOCAL_CFLAGS := -Werror
 include $(BUILD_EXECUTABLE)
 
diff --git a/applypatch/applypatch_main.cpp b/applypatch/applypatch_main.cpp
new file mode 100644
index 0000000..197077c
--- /dev/null
+++ b/applypatch/applypatch_main.cpp
@@ -0,0 +1,28 @@
+/*
+ * 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 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 "applypatch_modes.h"
+
+// This program (applypatch) applies binary patches to files in a way that
+// is safe (the original file is not touched until we have the desired
+// replacement for it) and idempotent (it's okay to run this program
+// multiple times).
+//
+// See the comments to applypatch_modes() function.
+
+int main(int argc, char** argv) {
+    return applypatch_modes(argc, const_cast<const char**>(argv));
+}
diff --git a/applypatch/main.cpp b/applypatch/applypatch_modes.cpp
similarity index 82%
rename from applypatch/main.cpp
rename to applypatch/applypatch_modes.cpp
index 988b6f9..7b191a8 100644
--- a/applypatch/main.cpp
+++ b/applypatch/applypatch_modes.cpp
@@ -14,6 +14,8 @@
  * limitations under the License.
  */
 
+#include "applypatch_modes.h"
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -23,12 +25,14 @@
 #include <string>
 #include <vector>
 
+#include <android-base/parseint.h>
+#include <android-base/strings.h>
 #include <openssl/sha.h>
 
 #include "applypatch/applypatch.h"
 #include "edify/expr.h"
 
-static int CheckMode(int argc, char** argv) {
+static int CheckMode(int argc, const char** argv) {
     if (argc < 3) {
         return 2;
     }
@@ -40,44 +44,42 @@
     return applypatch_check(argv[2], sha1);
 }
 
-static int SpaceMode(int argc, char** argv) {
+static int SpaceMode(int argc, const char** argv) {
     if (argc != 3) {
         return 2;
     }
-    char* endptr;
-    size_t bytes = strtol(argv[2], &endptr, 10);
-    if (bytes == 0 && endptr == argv[2]) {
+
+    size_t bytes;
+    if (!android::base::ParseUint(argv[2], &bytes) || bytes == 0) {
         printf("can't parse \"%s\" as byte count\n\n", argv[2]);
         return 1;
     }
     return CacheSizeCheck(bytes);
 }
 
-// Parse arguments (which should be of the form "<sha1>:<filename>"
-// into the new parallel arrays *sha1s and *files.Returns true on
-// success.
-static bool ParsePatchArgs(int argc, char** argv, std::vector<std::string>* sha1s,
+// Parse arguments (which should be of the form "<sha1>:<filename>" into the
+// new parallel arrays *sha1s and *files. Returns true on success.
+static bool ParsePatchArgs(int argc, const char** argv, std::vector<std::string>* sha1s,
                            std::vector<FileContents>* files) {
     if (sha1s == nullptr) {
         return false;
     }
     for (int i = 0; i < argc; ++i) {
-        uint8_t digest[SHA_DIGEST_LENGTH];
-        char* colon = strchr(argv[i], ':');
-        if (colon == nullptr) {
-            printf("no ':' in patch argument \"%s\"\n", argv[i]);
+        std::vector<std::string> pieces = android::base::Split(argv[i], ":");
+        if (pieces.size() != 2) {
+            printf("failed to parse patch argument \"%s\"\n", argv[i]);
             return false;
         }
-        *colon = '\0';
-        ++colon;
-        if (ParseSha1(argv[i], digest) != 0) {
+
+        uint8_t digest[SHA_DIGEST_LENGTH];
+        if (ParseSha1(pieces[0].c_str(), digest) != 0) {
             printf("failed to parse sha1 \"%s\"\n", argv[i]);
             return false;
         }
 
-        sha1s->push_back(argv[i]);
+        sha1s->push_back(pieces[0]);
         FileContents fc;
-        if (LoadFileContents(colon, &fc) != 0) {
+        if (LoadFileContents(pieces[1].c_str(), &fc) != 0) {
             return false;
         }
         files->push_back(std::move(fc));
@@ -90,7 +92,7 @@
     return applypatch_flash(src_filename, tgt_filename, tgt_sha1, tgt_size);
 }
 
-static int PatchMode(int argc, char** argv) {
+static int PatchMode(int argc, const char** argv) {
     FileContents bonusFc;
     Value bonus(VAL_INVALID, "");
 
@@ -109,9 +111,8 @@
         return 2;
     }
 
-    char* endptr;
-    size_t target_size = strtol(argv[4], &endptr, 10);
-    if (target_size == 0 && endptr == argv[4]) {
+    size_t target_size;
+    if (!android::base::ParseUint(argv[4], &target_size) || target_size == 0) {
         printf("can't parse \"%s\" as byte count\n\n", argv[4]);
         return 1;
     }
@@ -124,6 +125,7 @@
         }
         return FlashMode(argv[1], argv[2], argv[3], target_size);
     }
+
     std::vector<std::string> sha1s;
     std::vector<FileContents> files;
     if (!ParsePatchArgs(argc-5, argv+5, &sha1s, &files)) {
@@ -139,8 +141,8 @@
     return applypatch(argv[1], argv[2], argv[3], target_size, sha1s, patches, &bonus);
 }
 
-// This program applies binary patches to files in a way that is safe
-// (the original file is not touched until we have the desired
+// This program (applypatch) applies binary patches to files in a way that
+// is safe (the original file is not touched until we have the desired
 // replacement for it) and idempotent (it's okay to run this program
 // multiple times).
 //
@@ -166,7 +168,7 @@
 // to read the source data.  See the comments for the
 // LoadPartitionContents() function for the format of such a filename.
 
-int main(int argc, char** argv) {
+int applypatch_modes(int argc, const char** argv) {
     if (argc < 2) {
       usage:
         printf(
diff --git a/applypatch/applypatch_modes.h b/applypatch/applypatch_modes.h
new file mode 100644
index 0000000..3d9d08d
--- /dev/null
+++ b/applypatch/applypatch_modes.h
@@ -0,0 +1,22 @@
+/*
+ * 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 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.
+ */
+
+#ifndef _APPLYPATCH_MODES_H
+#define _APPLYPATCH_MODES_H
+
+int applypatch_modes(int argc, const char** argv);
+
+#endif // _APPLYPATCH_MODES_H
diff --git a/tests/Android.mk b/tests/Android.mk
index 3d05386..461d6ef 100644
--- a/tests/Android.mk
+++ b/tests/Android.mk
@@ -43,7 +43,7 @@
 # Component tests
 include $(CLEAR_VARS)
 LOCAL_CLANG := true
-LOCAL_CFLAGS += -Wno-unused-parameter -Werror
+LOCAL_CFLAGS := -Werror
 LOCAL_ADDITIONAL_DEPENDENCIES := $(LOCAL_PATH)/Android.mk
 LOCAL_MODULE := recovery_component_test
 LOCAL_C_INCLUDES := bootable/recovery
@@ -63,6 +63,7 @@
     libext2fs
 
 LOCAL_STATIC_LIBRARIES := \
+    libapplypatch_modes \
     libapplypatch \
     libedify \
     libotafault \
diff --git a/tests/component/applypatch_test.cpp b/tests/component/applypatch_test.cpp
index e09c1e7..f95ebed 100644
--- a/tests/component/applypatch_test.cpp
+++ b/tests/component/applypatch_test.cpp
@@ -33,149 +33,155 @@
 #include <openssl/sha.h>
 
 #include "applypatch/applypatch.h"
+#include "applypatch/applypatch_modes.h"
 #include "common/test_constants.h"
 #include "print_sha1.h"
 
 static const std::string DATA_PATH = getenv("ANDROID_DATA");
 static const std::string TESTDATA_PATH = "/recovery/testdata";
 
-static void sha1sum(const std::string& fname, std::string* sha1) {
-    ASSERT_NE(nullptr, sha1);
+static void sha1sum(const std::string& fname, std::string* sha1, size_t* fsize = nullptr) {
+  ASSERT_NE(nullptr, sha1);
 
-    std::string data;
-    ASSERT_TRUE(android::base::ReadFileToString(fname, &data));
+  std::string data;
+  ASSERT_TRUE(android::base::ReadFileToString(fname, &data));
 
-    uint8_t digest[SHA_DIGEST_LENGTH];
-    SHA1(reinterpret_cast<const uint8_t*>(data.c_str()), data.size(), digest);
-    *sha1 = print_sha1(digest);
+  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;
-    content.reserve(1024);
-    for (size_t i = 0; i < 1024; i++) {
-        content[i] = rand() % 256;
-    }
-    ASSERT_TRUE(android::base::WriteStringToFile(content, fname));
+  std::string content;
+  content.reserve(1024);
+  for (size_t i = 0; i < 1024; i++) {
+    content[i] = rand() % 256;
+  }
+  ASSERT_TRUE(android::base::WriteStringToFile(content, fname));
 }
 
 static bool file_cmp(const std::string& f1, const std::string& f2) {
-    std::string c1;
-    android::base::ReadFileToString(f1, &c1);
-    std::string c2;
-    android::base::ReadFileToString(f2, &c2);
-    return c1 == c2;
+  std::string c1;
+  android::base::ReadFileToString(f1, &c1);
+  std::string c2;
+  android::base::ReadFileToString(f2, &c2);
+  return c1 == c2;
 }
 
 static std::string from_testdata_base(const std::string& fname) {
-    return DATA_PATH + NATIVE_TEST_PATH + TESTDATA_PATH + "/" + fname;
+  return DATA_PATH + NATIVE_TEST_PATH + TESTDATA_PATH + "/" + fname;
 }
 
 class ApplyPatchTest : public ::testing::Test {
-  public:
-    static void SetUpTestCase() {
-        // set up files
-        old_file = from_testdata_base("old.file");
-        new_file = from_testdata_base("new.file");
-        patch_file = from_testdata_base("patch.bsdiff");
-        rand_file = "/cache/applypatch_test_rand.file";
-        cache_file = "/cache/saved.file";
+ public:
+  static void SetUpTestCase() {
+    // set up files
+    old_file = from_testdata_base("old.file");
+    new_file = from_testdata_base("new.file");
+    patch_file = from_testdata_base("patch.bsdiff");
+    rand_file = "/cache/applypatch_test_rand.file";
+    cache_file = "/cache/saved.file";
 
-        // write stuff to rand_file
-        ASSERT_TRUE(android::base::WriteStringToFile("hello", rand_file));
+    // write stuff to rand_file
+    ASSERT_TRUE(android::base::WriteStringToFile("hello", rand_file));
 
-        // set up SHA constants
-        sha1sum(old_file, &old_sha1);
-        sha1sum(new_file, &new_sha1);
-        srand(time(NULL));
-        bad_sha1_a = android::base::StringPrintf("%040x", rand());
-        bad_sha1_b = android::base::StringPrintf("%040x", rand());
+    // set up SHA constants
+    sha1sum(old_file, &old_sha1);
+    sha1sum(new_file, &new_sha1);
+    srand(time(nullptr));
+    bad_sha1_a = android::base::StringPrintf("%040x", rand());
+    bad_sha1_b = android::base::StringPrintf("%040x", rand());
 
-        struct stat st;
-        stat(&new_file[0], &st);
-        new_size = st.st_size;
-    }
+    struct stat st;
+    stat(&new_file[0], &st);
+    new_size = st.st_size;
+  }
 
-    static std::string old_file;
-    static std::string new_file;
-    static std::string rand_file;
-    static std::string cache_file;
-    static std::string patch_file;
+  static std::string old_file;
+  static std::string new_file;
+  static std::string rand_file;
+  static std::string cache_file;
+  static std::string patch_file;
 
-    static std::string old_sha1;
-    static std::string new_sha1;
-    static std::string bad_sha1_a;
-    static std::string bad_sha1_b;
+  static std::string old_sha1;
+  static std::string new_sha1;
+  static std::string bad_sha1_a;
+  static std::string bad_sha1_b;
 
-    static size_t new_size;
+  static size_t new_size;
 };
 
 std::string ApplyPatchTest::old_file;
 std::string ApplyPatchTest::new_file;
 
 static void cp(const std::string& src, const std::string& tgt) {
-    std::string cmd = "cp " + src + " " + tgt;
-    system(&cmd[0]);
+  std::string cmd = "cp " + src + " " + tgt;
+  system(cmd.c_str());
 }
 
 static void backup_old() {
-    cp(ApplyPatchTest::old_file, ApplyPatchTest::cache_file);
+  cp(ApplyPatchTest::old_file, ApplyPatchTest::cache_file);
 }
 
 static void restore_old() {
-    cp(ApplyPatchTest::cache_file, ApplyPatchTest::old_file);
+  cp(ApplyPatchTest::cache_file, ApplyPatchTest::old_file);
 }
 
 class ApplyPatchCacheTest : public ApplyPatchTest {
-  public:
-    virtual void SetUp() {
-        backup_old();
-    }
+ public:
+  virtual void SetUp() {
+    backup_old();
+  }
 
-    virtual void TearDown() {
-        restore_old();
-    }
+  virtual void TearDown() {
+    restore_old();
+  }
 };
 
 class ApplyPatchFullTest : public ApplyPatchCacheTest {
-  public:
-    static void SetUpTestCase() {
-        ApplyPatchTest::SetUpTestCase();
+ public:
+  static void SetUpTestCase() {
+    ApplyPatchTest::SetUpTestCase();
 
-        output_f = new TemporaryFile();
-        output_loc = std::string(output_f->path);
+    output_f = new TemporaryFile();
+    output_loc = std::string(output_f->path);
 
-        struct FileContents fc;
+    struct FileContents fc;
 
-        ASSERT_EQ(0, LoadFileContents(&rand_file[0], &fc));
-        patches.push_back(
-            std::make_unique<Value>(VAL_BLOB, std::string(fc.data.begin(), fc.data.end())));
+    ASSERT_EQ(0, LoadFileContents(&rand_file[0], &fc));
+    patches.push_back(
+        std::make_unique<Value>(VAL_BLOB, std::string(fc.data.begin(), fc.data.end())));
 
-        ASSERT_EQ(0, LoadFileContents(&patch_file[0], &fc));
-        patches.push_back(
-            std::make_unique<Value>(VAL_BLOB, std::string(fc.data.begin(), fc.data.end())));
-    }
+    ASSERT_EQ(0, LoadFileContents(&patch_file[0], &fc));
+    patches.push_back(
+        std::make_unique<Value>(VAL_BLOB, std::string(fc.data.begin(), fc.data.end())));
+  }
 
-    static void TearDownTestCase() {
-        delete output_f;
-    }
+  static void TearDownTestCase() {
+    delete output_f;
+    patches.clear();
+  }
 
-    static std::vector<std::unique_ptr<Value>> patches;
-    static TemporaryFile* output_f;
-    static std::string output_loc;
+  static std::vector<std::unique_ptr<Value>> patches;
+  static TemporaryFile* output_f;
+  static std::string output_loc;
 };
 
 class ApplyPatchDoubleCacheTest : public ApplyPatchFullTest {
-  public:
-    virtual void SetUp() {
-        ApplyPatchCacheTest::SetUp();
-        cp(cache_file, "/cache/reallysaved.file");
-    }
+ public:
+  virtual void SetUp() {
+    ApplyPatchCacheTest::SetUp();
+    cp(cache_file, "/cache/reallysaved.file");
+  }
 
-    virtual void TearDown() {
-        cp("/cache/reallysaved.file", cache_file);
-        ApplyPatchCacheTest::TearDown();
-    }
+  virtual void TearDown() {
+    cp("/cache/reallysaved.file", cache_file);
+    ApplyPatchCacheTest::TearDown();
+  }
 };
 
 std::string ApplyPatchTest::rand_file;
@@ -193,203 +199,263 @@
 std::string ApplyPatchFullTest::output_loc;
 
 TEST_F(ApplyPatchTest, CheckModeSkip) {
-    std::vector<std::string> sha1s;
-    ASSERT_EQ(0, applypatch_check(&old_file[0], sha1s));
+  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));
+  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));
+  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));
+  std::vector<std::string> sha1s = { bad_sha1_a, bad_sha1_b };
+  ASSERT_NE(0, applypatch_check(&old_file[0], sha1s));
 }
 
 TEST_F(ApplyPatchCacheTest, CheckCacheCorruptedSingle) {
-    mangle_file(old_file);
-    std::vector<std::string> sha1s = { old_sha1 };
-    ASSERT_EQ(0, applypatch_check(&old_file[0], sha1s));
+  mangle_file(old_file);
+  std::vector<std::string> sha1s = { old_sha1 };
+  ASSERT_EQ(0, applypatch_check(&old_file[0], sha1s));
 }
 
 TEST_F(ApplyPatchCacheTest, CheckCacheCorruptedMultiple) {
-    mangle_file(old_file);
-    std::vector<std::string> sha1s = {
-        bad_sha1_a,
-        old_sha1,
-        bad_sha1_b
-    };
-    ASSERT_EQ(0, applypatch_check(&old_file[0], sha1s));
+  mangle_file(old_file);
+  std::vector<std::string> sha1s = { bad_sha1_a, old_sha1, bad_sha1_b };
+  ASSERT_EQ(0, applypatch_check(&old_file[0], sha1s));
 }
 
 TEST_F(ApplyPatchCacheTest, CheckCacheCorruptedFailure) {
-    mangle_file(old_file);
-    std::vector<std::string> sha1s = {
-        bad_sha1_a,
-        bad_sha1_b
-    };
-    ASSERT_NE(0, applypatch_check(&old_file[0], sha1s));
+  mangle_file(old_file);
+  std::vector<std::string> sha1s = { bad_sha1_a, bad_sha1_b };
+  ASSERT_NE(0, applypatch_check(&old_file[0], sha1s));
 }
 
 TEST_F(ApplyPatchCacheTest, CheckCacheMissingSingle) {
-    unlink(&old_file[0]);
-    std::vector<std::string> sha1s = { old_sha1 };
-    ASSERT_EQ(0, applypatch_check(&old_file[0], sha1s));
+  unlink(&old_file[0]);
+  std::vector<std::string> sha1s = { old_sha1 };
+  ASSERT_EQ(0, applypatch_check(&old_file[0], sha1s));
 }
 
 TEST_F(ApplyPatchCacheTest, CheckCacheMissingMultiple) {
-    unlink(&old_file[0]);
-    std::vector<std::string> sha1s = {
-        bad_sha1_a,
-        old_sha1,
-        bad_sha1_b
-    };
-    ASSERT_EQ(0, applypatch_check(&old_file[0], sha1s));
+  unlink(&old_file[0]);
+  std::vector<std::string> sha1s = { bad_sha1_a, old_sha1, bad_sha1_b };
+  ASSERT_EQ(0, applypatch_check(&old_file[0], sha1s));
 }
 
 TEST_F(ApplyPatchCacheTest, CheckCacheMissingFailure) {
-    unlink(&old_file[0]);
-    std::vector<std::string> sha1s = {
-        bad_sha1_a,
-        bad_sha1_b
-    };
-    ASSERT_NE(0, applypatch_check(&old_file[0], sha1s));
+  unlink(&old_file[0]);
+  std::vector<std::string> sha1s = { bad_sha1_a, bad_sha1_b };
+  ASSERT_NE(0, applypatch_check(&old_file[0], sha1s));
 }
 
 TEST_F(ApplyPatchFullTest, ApplyInPlace) {
-    std::vector<std::string> sha1s = {
-        bad_sha1_a,
-        old_sha1
-    };
-    int ap_result = applypatch(&old_file[0],
-            "-",
-            &new_sha1[0],
-            new_size,
-            sha1s,
-            patches,
-            nullptr);
-    ASSERT_EQ(0, ap_result);
-    ASSERT_TRUE(file_cmp(old_file, new_file));
-    // reapply, applypatch is idempotent so it should succeed
-    ap_result = applypatch(&old_file[0],
-            "-",
-            &new_sha1[0],
-            new_size,
-            sha1s,
-            patches,
-            nullptr);
-    ASSERT_EQ(0, ap_result);
-    ASSERT_TRUE(file_cmp(old_file, new_file));
+  std::vector<std::string> sha1s = { bad_sha1_a, old_sha1 };
+  ASSERT_EQ(0, applypatch(&old_file[0], "-", &new_sha1[0], new_size, sha1s, patches, nullptr));
+  ASSERT_TRUE(file_cmp(old_file, new_file));
+
+  // reapply, applypatch is idempotent so it should succeed
+  ASSERT_EQ(0, applypatch(&old_file[0], "-", &new_sha1[0], new_size, sha1s, patches, nullptr));
+  ASSERT_TRUE(file_cmp(old_file, new_file));
 }
 
 TEST_F(ApplyPatchFullTest, ApplyInNewLocation) {
-    std::vector<std::string> sha1s = {
-        bad_sha1_a,
-        old_sha1
-    };
-    // Apply bsdiff patch to new location.
-    ASSERT_EQ(0, applypatch(&old_file[0],
-            &output_loc[0],
-            &new_sha1[0],
-            new_size,
-            sha1s,
-            patches,
-            nullptr));
-    ASSERT_TRUE(file_cmp(output_loc, new_file));
+  std::vector<std::string> sha1s = { bad_sha1_a, old_sha1 };
+  // Apply bsdiff patch to new location.
+  ASSERT_EQ(
+      0, applypatch(&old_file[0], &output_loc[0], &new_sha1[0], new_size, sha1s, patches, nullptr));
+  ASSERT_TRUE(file_cmp(output_loc, new_file));
 
-    // Reapply to the same location.
-    ASSERT_EQ(0, applypatch(&old_file[0],
-            &output_loc[0],
-            &new_sha1[0],
-            new_size,
-            sha1s,
-            patches,
-            nullptr));
-    ASSERT_TRUE(file_cmp(output_loc, new_file));
+  // Reapply to the same location.
+  ASSERT_EQ(
+      0, applypatch(&old_file[0], &output_loc[0], &new_sha1[0], new_size, sha1s, patches, nullptr));
+  ASSERT_TRUE(file_cmp(output_loc, new_file));
 }
 
 TEST_F(ApplyPatchFullTest, ApplyCorruptedInNewLocation) {
-    std::vector<std::string> sha1s = {
-        bad_sha1_a,
-        old_sha1
-    };
-    // Apply bsdiff patch to new location with corrupted source.
-    mangle_file(old_file);
-    int ap_result = applypatch(&old_file[0],
-            &output_loc[0],
-            &new_sha1[0],
-            new_size,
-            sha1s,
-            patches,
-            nullptr);
-    ASSERT_EQ(0, ap_result);
-    ASSERT_TRUE(file_cmp(output_loc, new_file));
+  std::vector<std::string> sha1s = { bad_sha1_a, old_sha1 };
+  // Apply bsdiff patch to new location with corrupted source.
+  mangle_file(old_file);
+  ASSERT_EQ(
+      0, applypatch(&old_file[0], &output_loc[0], &new_sha1[0], new_size, sha1s, patches, nullptr));
+  ASSERT_TRUE(file_cmp(output_loc, new_file));
 
-    // Reapply bsdiff patch to new location with corrupted source.
-    ap_result = applypatch(&old_file[0],
-            &output_loc[0],
-            &new_sha1[0],
-            new_size,
-            sha1s,
-            patches,
-            nullptr);
-    ASSERT_EQ(0, ap_result);
-    ASSERT_TRUE(file_cmp(output_loc, new_file));
+  // Reapply bsdiff patch to new location with corrupted source.
+  ASSERT_EQ(
+      0, applypatch(&old_file[0], &output_loc[0], &new_sha1[0], new_size, sha1s, patches, nullptr));
+  ASSERT_TRUE(file_cmp(output_loc, new_file));
 }
 
 TEST_F(ApplyPatchDoubleCacheTest, ApplyDoubleCorruptedInNewLocation) {
-    std::vector<std::string> sha1s = {
-        bad_sha1_a,
-        old_sha1
-    };
+  std::vector<std::string> sha1s = { bad_sha1_a, old_sha1 };
 
-    // Apply bsdiff patch to new location with corrupted source and copy (no new file).
-    // Expected to fail.
-    mangle_file(old_file);
-    mangle_file(cache_file);
-    int ap_result = applypatch(&old_file[0],
-            &output_loc[0],
-            &new_sha1[0],
-            new_size,
-            sha1s,
-            patches,
-            nullptr);
-    ASSERT_NE(0, ap_result);
-    ASSERT_FALSE(file_cmp(output_loc, new_file));
+  // Apply bsdiff patch to new location with corrupted source and copy (no new file).
+  // Expected to fail.
+  mangle_file(old_file);
+  mangle_file(cache_file);
+  ASSERT_NE(
+      0, applypatch(&old_file[0], &output_loc[0], &new_sha1[0], new_size, sha1s, patches, nullptr));
+  ASSERT_FALSE(file_cmp(output_loc, new_file));
 
-    // Expected to fail again on retry.
-    ap_result = applypatch(&old_file[0],
-            &output_loc[0],
-            &new_sha1[0],
-            new_size,
-            sha1s,
-            patches,
-            nullptr);
-    ASSERT_NE(0, ap_result);
-    ASSERT_FALSE(file_cmp(output_loc, new_file));
+  // Expected to fail again on retry.
+  ASSERT_NE(
+      0, applypatch(&old_file[0], &output_loc[0], &new_sha1[0], new_size, sha1s, patches, nullptr));
+  ASSERT_FALSE(file_cmp(output_loc, new_file));
 
-    // Expected to fail with incorrect new file.
-    mangle_file(output_loc);
-    ap_result = applypatch(&old_file[0],
-            &output_loc[0],
-            &new_sha1[0],
-            new_size,
-            sha1s,
-            patches,
-            nullptr);
-    ASSERT_NE(0, ap_result);
-    ASSERT_FALSE(file_cmp(output_loc, new_file));
+  // Expected to fail with incorrect new file.
+  mangle_file(output_loc);
+  ASSERT_NE(
+      0, applypatch(&old_file[0], &output_loc[0], &new_sha1[0], new_size, sha1s, patches, nullptr));
+  ASSERT_FALSE(file_cmp(output_loc, new_file));
+}
+
+TEST(ApplyPatchModes, 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(ApplyPatchModes, PatchMode) {
+  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 bonus_file = from_testdata_base("bonus.file");
+
+  // applypatch -b <bonus-file> <src-file> <tgt-file> <tgt-sha1> <tgt-size> <src-sha1>:<patch>
+  TemporaryFile tmp1;
+  std::vector<const char*> args = {
+    "applypatch",
+    "-b",
+    bonus_file.c_str(),
+    boot_img.c_str(),
+    tmp1.path,
+    recovery_img_sha1.c_str(),
+    std::to_string(recovery_img_size).c_str(),
+    (boot_img_sha1 + ":" + from_testdata_base("recovery-from-boot.p")).c_str()
+  };
+  ASSERT_EQ(0, applypatch_modes(args.size(), args.data()));
+
+  // applypatch <src-file> <tgt-file> <tgt-sha1> <tgt-size> <src-sha1>:<patch>
+  TemporaryFile tmp2;
+  std::vector<const char*> args2 = {
+    "applypatch",
+    boot_img.c_str(),
+    tmp2.path,
+    recovery_img_sha1.c_str(),
+    std::to_string(recovery_img_size).c_str(),
+    (boot_img_sha1 + ":" + from_testdata_base("recovery-from-boot-with-bonus.p")).c_str()
+  };
+  ASSERT_EQ(0, applypatch_modes(args2.size(), args2.data()));
+
+  // applypatch -b <bonus-file> <src-file> <tgt-file> <tgt-sha1> <tgt-size> \
+    //               <src-sha1-fake>:<patch1> <src-sha1>:<patch2>
+  TemporaryFile tmp3;
+  std::string bad_sha1_a = android::base::StringPrintf("%040x", rand());
+  std::string bad_sha1_b = android::base::StringPrintf("%040x", rand());
+  std::vector<const char*> args3 = {
+    "applypatch",
+    "-b",
+    bonus_file.c_str(),
+    boot_img.c_str(),
+    tmp3.path,
+    recovery_img_sha1.c_str(),
+    std::to_string(recovery_img_size).c_str(),
+    (bad_sha1_a + ":" + from_testdata_base("recovery-from-boot.p")).c_str(),
+    (boot_img_sha1 + ":" + from_testdata_base("recovery-from-boot.p")).c_str(),
+    (bad_sha1_b + ":" + from_testdata_base("recovery-from-boot.p")).c_str(),
+  };
+  ASSERT_EQ(0, applypatch_modes(args3.size(), args3.data()));
+}
+
+TEST(ApplyPatchModes, 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 recovery_img_size;
+  std::string recovery_img_sha1;
+  sha1sum(recovery_img, &recovery_img_sha1, &recovery_img_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(),
+    std::to_string(recovery_img_size).c_str() };
+  ASSERT_NE(0, applypatch_modes(args4.size(), args4.data()));
+
+  // Failed to parse patch args.
+  TemporaryFile tmp5;
+  std::vector<const char*> args5 = {
+    "applypatch",
+    boot_img.c_str(),
+    tmp5.path,
+    recovery_img_sha1.c_str(),
+    std::to_string(recovery_img_size).c_str(),
+    ("invalid-sha1:filename" + from_testdata_base("recovery-from-boot-with-bonus.p")).c_str(),
+  };
+  ASSERT_NE(0, applypatch_modes(args5.size(), args5.data()));
+
+  // Target size cannot be zero.
+  TemporaryFile tmp6;
+  std::vector<const char*> args6 = {
+    "applypatch",
+    boot_img.c_str(),
+    tmp6.path,
+    recovery_img_sha1.c_str(),
+    "0",  // target size
+    (boot_img_sha1 + ":" + from_testdata_base("recovery-from-boot-with-bonus.p")).c_str()
+  };
+  ASSERT_NE(0, applypatch_modes(args6.size(), args6.data()));
+}
+
+TEST(ApplyPatchModes, CheckModeInvalidArgs) {
+  // Insufficient args.
+  ASSERT_EQ(2, applypatch_modes(2, (const char* []){ "applypatch", "-c" }));
+}
+
+TEST(ApplyPatchModes, SpaceModeInvalidArgs) {
+  // Insufficient args.
+  ASSERT_EQ(2, applypatch_modes(2, (const char* []){ "applypatch", "-s" }));
+
+  // Invalid bytes arg.
+  ASSERT_EQ(1, applypatch_modes(3, (const char* []){ "applypatch", "-s", "x" }));
+
+  // 0 is invalid.
+  ASSERT_EQ(1, applypatch_modes(3, (const char* []){ "applypatch", "-s", "0" }));
+
+  // 0x10 is fine.
+  ASSERT_EQ(0, applypatch_modes(3, (const char* []){ "applypatch", "-s", "0x10" }));
+}
+
+TEST(ApplyPatchModes, ShowLicenses) {
+  ASSERT_EQ(0, applypatch_modes(2, (const char* []){ "applypatch", "-l" }));
 }
diff --git a/tests/testdata/bonus.file b/tests/testdata/bonus.file
new file mode 100644
index 0000000..918ef8a
--- /dev/null
+++ b/tests/testdata/bonus.file
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diff --git a/tests/testdata/boot.img b/tests/testdata/boot.img
new file mode 100644
index 0000000..dd48975
--- /dev/null
+++ b/tests/testdata/boot.img
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diff --git a/tests/testdata/recovery-from-boot-with-bonus.p b/tests/testdata/recovery-from-boot-with-bonus.p
new file mode 100644
index 0000000..08b6f55
--- /dev/null
+++ b/tests/testdata/recovery-from-boot-with-bonus.p
Binary files differ
diff --git a/tests/testdata/recovery-from-boot.p b/tests/testdata/recovery-from-boot.p
new file mode 100644
index 0000000..06f6c29
--- /dev/null
+++ b/tests/testdata/recovery-from-boot.p
Binary files differ
diff --git a/tests/testdata/recovery.img b/tests/testdata/recovery.img
new file mode 100644
index 0000000..b862e6f
--- /dev/null
+++ b/tests/testdata/recovery.img
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