diff --git a/tools/releasetools/TEST_MAPPING b/tools/releasetools/TEST_MAPPING
new file mode 100644
index 0000000..77cef07
--- /dev/null
+++ b/tools/releasetools/TEST_MAPPING
@@ -0,0 +1,8 @@
+{
+  "presubmit": [
+    {
+      "name": "releasetools_test",
+      "host": true
+    }
+  ]
+}
diff --git a/tools/releasetools/test_add_img_to_target_files.py b/tools/releasetools/test_add_img_to_target_files.py
index 482f86c..013ade6 100644
--- a/tools/releasetools/test_add_img_to_target_files.py
+++ b/tools/releasetools/test_add_img_to_target_files.py
@@ -34,18 +34,6 @@
   def setUp(self):
     OPTIONS.input_tmp = common.MakeTempDir()
 
-  def _verifyCareMap(self, expected, file_name):
-    """Parses the care_map.pb; and checks the content in plain text."""
-    text_file = common.MakeTempFile(prefix="caremap-", suffix=".txt")
-
-    # Calls an external binary to convert the proto message.
-    cmd = ["care_map_generator", "--parse_proto", file_name, text_file]
-    common.RunAndCheckOutput(cmd)
-
-    with open(text_file, 'r') as verify_fp:
-      plain_text = verify_fp.read()
-    self.assertEqual('\n'.join(expected), plain_text)
-
   @staticmethod
   def _create_images(images, prefix):
     """Creates images under OPTIONS.input_tmp/prefix."""
@@ -164,6 +152,19 @@
     }
     return image_paths
 
+  def _verifyCareMap(self, expected, file_name):
+    """Parses the care_map.pb; and checks the content in plain text."""
+    text_file = common.MakeTempFile(prefix="caremap-", suffix=".txt")
+
+    # Calls an external binary to convert the proto message.
+    cmd = ["care_map_generator", "--parse_proto", file_name, text_file]
+    common.RunAndCheckOutput(cmd)
+
+    with open(text_file) as verify_fp:
+      plain_text = verify_fp.read()
+    self.assertEqual('\n'.join(expected), plain_text)
+
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_AddCareMapForAbOta(self):
     image_paths = self._test_AddCareMapForAbOta()
 
@@ -179,6 +180,7 @@
 
     self._verifyCareMap(expected, care_map_file)
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_AddCareMapForAbOta_withNonCareMapPartitions(self):
     """Partitions without care_map should be ignored."""
     image_paths = self._test_AddCareMapForAbOta()
@@ -196,6 +198,7 @@
 
     self._verifyCareMap(expected, care_map_file)
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_AddCareMapForAbOta_withAvb(self):
     """Tests the case for device using AVB."""
     image_paths = self._test_AddCareMapForAbOta()
@@ -223,6 +226,7 @@
 
     self._verifyCareMap(expected, care_map_file)
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_AddCareMapForAbOta_noFingerprint(self):
     """Tests the case for partitions without fingerprint."""
     image_paths = self._test_AddCareMapForAbOta()
@@ -240,6 +244,7 @@
 
     self._verifyCareMap(expected, care_map_file)
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_AddCareMapForAbOta_withThumbprint(self):
     """Tests the case for partitions with thumbprint."""
     image_paths = self._test_AddCareMapForAbOta()
@@ -282,6 +287,7 @@
     self.assertRaises(AssertionError, AddCareMapForAbOta, None,
                       ['system', 'vendor'], image_paths)
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_AddCareMapForAbOta_zipOutput(self):
     """Tests the case with ZIP output."""
     image_paths = self._test_AddCareMapForAbOta()
@@ -304,6 +310,7 @@
                 "google/sailfish/678:user/dev-keys"]
     self._verifyCareMap(expected, os.path.join(temp_dir, care_map_name))
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_AddCareMapForAbOta_zipOutput_careMapEntryExists(self):
     """Tests the case with ZIP output which already has care_map entry."""
     image_paths = self._test_AddCareMapForAbOta()
@@ -338,6 +345,7 @@
     self.assertEqual(
         ['--include_descriptors_from_image', '/path/to/system.img'], cmd)
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_AppendVBMetaArgsForPartition_vendorAsChainedPartition(self):
     testdata_dir = test_utils.get_testdata_dir()
     pubkey = os.path.join(testdata_dir, 'testkey.pubkey.pem')
diff --git a/tools/releasetools/test_apex_utils.py b/tools/releasetools/test_apex_utils.py
index 76d4d58..c7d5807 100644
--- a/tools/releasetools/test_apex_utils.py
+++ b/tools/releasetools/test_apex_utils.py
@@ -39,6 +39,7 @@
       payload_fp.write(os.urandom(8192))
     return payload_file
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_ParseApexPayloadInfo(self):
     payload_file = self._GetTestPayload()
     apex_utils.SignApexPayload(
@@ -48,12 +49,14 @@
     self.assertEqual(self.SALT, payload_info['Salt'])
     self.assertEqual('testkey', payload_info['apex.key'])
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_SignApexPayload(self):
     payload_file = self._GetTestPayload()
     apex_utils.SignApexPayload(
         payload_file, self.payload_key, 'testkey', 'SHA256_RSA2048', self.SALT)
     apex_utils.VerifyApexPayload(payload_file, self.payload_key)
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_SignApexPayload_withSignerHelper(self):
     payload_file = self._GetTestPayload()
     signing_helper = os.path.join(self.testdata_dir, 'signing_helper.sh')
@@ -67,6 +70,7 @@
         payload_signer_args)
     apex_utils.VerifyApexPayload(payload_file, self.payload_key)
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_SignApexPayload_invalidKey(self):
     self.assertRaises(
         apex_utils.ApexSigningError,
@@ -77,6 +81,7 @@
         'SHA256_RSA2048',
         self.SALT)
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_VerifyApexPayload_wrongKey(self):
     payload_file = self._GetTestPayload()
     apex_utils.SignApexPayload(
diff --git a/tools/releasetools/test_build_image.py b/tools/releasetools/test_build_image.py
index 1cebd0c..b24805f 100644
--- a/tools/releasetools/test_build_image.py
+++ b/tools/releasetools/test_build_image.py
@@ -18,12 +18,13 @@
 import os.path
 
 import common
+import test_utils
 from build_image import (
-    BuildImageError, CheckHeadroom, GetFilesystemCharacteristics, SetUpInDirAndFsConfig)
-from test_utils import ReleaseToolsTestCase
+    BuildImageError, CheckHeadroom, GetFilesystemCharacteristics,
+    SetUpInDirAndFsConfig)
 
 
-class BuildImageTest(ReleaseToolsTestCase):
+class BuildImageTest(test_utils.ReleaseToolsTestCase):
 
   # Available: 1000 blocks.
   EXT4FS_OUTPUT = (
@@ -48,6 +49,7 @@
     self.assertRaises(
         BuildImageError, CheckHeadroom, self.EXT4FS_OUTPUT, prop_dict)
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_CheckHeadroom_WrongFsType(self):
     prop_dict = {
         'fs_type' : 'f2fs',
@@ -72,6 +74,7 @@
     self.assertRaises(
         AssertionError, CheckHeadroom, self.EXT4FS_OUTPUT, prop_dict)
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_CheckHeadroom_WithMke2fsOutput(self):
     """Tests the result parsing from actual call to mke2fs."""
     input_dir = common.MakeTempDir()
@@ -177,13 +180,14 @@
     self.assertIn('fs-config-root\n', fs_config_data)
     self.assertEqual('/', prop_dict['mount_point'])
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_GetFilesystemCharacteristics(self):
     input_dir = common.MakeTempDir()
     output_image = common.MakeTempFile(suffix='.img')
     command = ['mkuserimg_mke2fs', input_dir, output_image, 'ext4',
                '/system', '409600', '-j', '0']
     proc = common.Run(command)
-    ext4fs_output, _ = proc.communicate()
+    proc.communicate()
     self.assertEqual(0, proc.returncode)
 
     output_file = common.MakeTempFile(suffix='.img')
diff --git a/tools/releasetools/test_common.py b/tools/releasetools/test_common.py
index 89add40..9b76734 100644
--- a/tools/releasetools/test_common.py
+++ b/tools/releasetools/test_common.py
@@ -315,6 +315,7 @@
     finally:
       os.remove(zip_file_name)
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_ZipDelete(self):
     zip_file = tempfile.NamedTemporaryFile(delete=False, suffix='.zip')
     output_zip = zipfile.ZipFile(zip_file.name, 'w',
@@ -376,6 +377,7 @@
     common.ZipClose(output_zip)
     return zip_file
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_UnzipTemp(self):
     zip_file = self._test_UnzipTemp_createZipFile()
     unzipped_dir = common.UnzipTemp(zip_file)
@@ -385,6 +387,7 @@
     self.assertTrue(os.path.exists(os.path.join(unzipped_dir, 'Bar4')))
     self.assertTrue(os.path.exists(os.path.join(unzipped_dir, 'Dir5/Baz5')))
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_UnzipTemp_withPatterns(self):
     zip_file = self._test_UnzipTemp_createZipFile()
 
@@ -425,6 +428,7 @@
     self.assertFalse(os.path.exists(os.path.join(unzipped_dir, 'Bar4')))
     self.assertFalse(os.path.exists(os.path.join(unzipped_dir, 'Dir5/Baz5')))
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_UnzipTemp_withPartiallyMatchingPatterns(self):
     zip_file = self._test_UnzipTemp_createZipFile()
     unzipped_dir = common.UnzipTemp(zip_file, ['Test*', 'Nonexistent*'])
@@ -575,6 +579,7 @@
     wrong_input = os.path.join(self.testdata_dir, 'testkey.pk8')
     self.assertRaises(AssertionError, common.ExtractPublicKey, wrong_input)
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_ExtractAvbPublicKey(self):
     privkey = os.path.join(self.testdata_dir, 'testkey.key')
     pubkey = os.path.join(self.testdata_dir, 'testkey.pubkey.pem')
@@ -594,18 +599,22 @@
       actual = common.ParseCertificate(cert_fp.read())
     self.assertEqual(expected, actual)
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_GetMinSdkVersion(self):
     test_app = os.path.join(self.testdata_dir, 'TestApp.apk')
     self.assertEqual('24', common.GetMinSdkVersion(test_app))
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_GetMinSdkVersion_invalidInput(self):
     self.assertRaises(
         common.ExternalError, common.GetMinSdkVersion, 'does-not-exist.apk')
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_GetMinSdkVersionInt(self):
     test_app = os.path.join(self.testdata_dir, 'TestApp.apk')
     self.assertEqual(24, common.GetMinSdkVersionInt(test_app, {}))
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_GetMinSdkVersionInt_invalidInput(self):
     self.assertRaises(
         common.ExternalError, common.GetMinSdkVersionInt, 'does-not-exist.apk',
@@ -617,6 +626,7 @@
   def setUp(self):
     self.testdata_dir = test_utils.get_testdata_dir()
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_GetSparseImage_emptyBlockMapFile(self):
     target_files = common.MakeTempFile(prefix='target_files-', suffix='.zip')
     with zipfile.ZipFile(target_files, 'w') as target_files_zip:
@@ -649,6 +659,7 @@
         AssertionError, common.GetSparseImage, 'unknown', self.testdata_dir,
         None, False)
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_GetSparseImage_missingBlockMapFile(self):
     target_files = common.MakeTempFile(prefix='target_files-', suffix='.zip')
     with zipfile.ZipFile(target_files, 'w') as target_files_zip:
@@ -667,6 +678,7 @@
           AssertionError, common.GetSparseImage, 'system', tempdir, input_zip,
           False)
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_GetSparseImage_sharedBlocks_notAllowed(self):
     """Tests the case of having overlapping blocks but disallowed."""
     target_files = common.MakeTempFile(prefix='target_files-', suffix='.zip')
@@ -689,6 +701,7 @@
           AssertionError, common.GetSparseImage, 'system', tempdir, input_zip,
           False)
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_GetSparseImage_sharedBlocks_allowed(self):
     """Tests the case for target using BOARD_EXT4_SHARE_DUP_BLOCKS := true."""
     target_files = common.MakeTempFile(prefix='target_files-', suffix='.zip')
@@ -731,6 +744,7 @@
     self.assertFalse(sparse_image.file_map['__NONZERO-0'].extra)
     self.assertFalse(sparse_image.file_map['/system/file1'].extra)
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_GetSparseImage_incompleteRanges(self):
     """Tests the case of ext4 images with holes."""
     target_files = common.MakeTempFile(prefix='target_files-', suffix='.zip')
@@ -754,6 +768,7 @@
     self.assertFalse(sparse_image.file_map['/system/file1'].extra)
     self.assertTrue(sparse_image.file_map['/system/file2'].extra['incomplete'])
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_GetSparseImage_systemRootImage_filenameWithExtraLeadingSlash(self):
     target_files = common.MakeTempFile(prefix='target_files-', suffix='.zip')
     with zipfile.ZipFile(target_files, 'w') as target_files_zip:
@@ -781,6 +796,7 @@
     self.assertTrue(
         sparse_image.file_map['/system/app/file3'].extra['incomplete'])
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_GetSparseImage_systemRootImage_nonSystemFiles(self):
     target_files = common.MakeTempFile(prefix='target_files-', suffix='.zip')
     with zipfile.ZipFile(target_files, 'w') as target_files_zip:
@@ -803,6 +819,7 @@
     self.assertFalse(sparse_image.file_map['//system/file1'].extra)
     self.assertTrue(sparse_image.file_map['//init.rc'].extra['incomplete'])
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_GetSparseImage_fileNotFound(self):
     target_files = common.MakeTempFile(prefix='target_files-', suffix='.zip')
     with zipfile.ZipFile(target_files, 'w') as target_files_zip:
@@ -822,6 +839,7 @@
           AssertionError, common.GetSparseImage, 'system', tempdir, input_zip,
           False)
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_GetAvbChainedPartitionArg(self):
     pubkey = os.path.join(self.testdata_dir, 'testkey.pubkey.pem')
     info_dict = {
@@ -835,6 +853,7 @@
     self.assertEqual('2', args[1])
     self.assertTrue(os.path.exists(args[2]))
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_GetAvbChainedPartitionArg_withPrivateKey(self):
     key = os.path.join(self.testdata_dir, 'testkey.key')
     info_dict = {
@@ -848,6 +867,7 @@
     self.assertEqual('2', args[1])
     self.assertTrue(os.path.exists(args[2]))
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_GetAvbChainedPartitionArg_withSpecifiedKey(self):
     info_dict = {
         'avb_avbtool': 'avbtool',
@@ -862,6 +882,7 @@
     self.assertEqual('2', args[1])
     self.assertTrue(os.path.exists(args[2]))
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_GetAvbChainedPartitionArg_invalidKey(self):
     pubkey = os.path.join(self.testdata_dir, 'testkey_with_passwd.x509.pem')
     info_dict = {
@@ -922,6 +943,7 @@
       self.assertIn('/', loaded_dict['fstab'])
       self.assertIn('/system', loaded_dict['fstab'])
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_LoadInfoDict_dirInput(self):
     target_files = self._test_LoadInfoDict_createTargetFiles(
         self.INFO_DICT_DEFAULT,
@@ -933,6 +955,7 @@
     self.assertIn('/', loaded_dict['fstab'])
     self.assertIn('/system', loaded_dict['fstab'])
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_LoadInfoDict_dirInput_legacyRecoveryFstabPath(self):
     target_files = self._test_LoadInfoDict_createTargetFiles(
         self.INFO_DICT_DEFAULT,
@@ -990,6 +1013,7 @@
       self.assertEqual(2, loaded_dict['fstab_version'])
       self.assertIsNone(loaded_dict['fstab'])
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_LoadInfoDict_missingMetaMiscInfoTxt(self):
     target_files = self._test_LoadInfoDict_createTargetFiles(
         self.INFO_DICT_DEFAULT,
@@ -998,6 +1022,7 @@
     with zipfile.ZipFile(target_files, 'r') as target_files_zip:
       self.assertRaises(ValueError, common.LoadInfoDict, target_files_zip)
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_LoadInfoDict_repacking(self):
     target_files = self._test_LoadInfoDict_createTargetFiles(
         self.INFO_DICT_DEFAULT,
@@ -1066,6 +1091,7 @@
     validate_target_files.ValidateInstallRecoveryScript(self._tempdir,
                                                         self._info)
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_recovery_from_boot(self):
     recovery_image = common.File("recovery.img", self.recovery_data)
     self._out_tmp_sink("recovery.img", recovery_image.data, "IMAGES")
diff --git a/tools/releasetools/test_merge_target_files.py b/tools/releasetools/test_merge_target_files.py
index bb9ce8e..ec452a8 100644
--- a/tools/releasetools/test_merge_target_files.py
+++ b/tools/releasetools/test_merge_target_files.py
@@ -16,7 +16,6 @@
 
 import os.path
 
-import common
 import test_utils
 from merge_target_files import (
     read_config_list, validate_config_lists, default_system_item_list,
diff --git a/tools/releasetools/test_ota_from_target_files.py b/tools/releasetools/test_ota_from_target_files.py
index bb0236b..bf94cc2 100644
--- a/tools/releasetools/test_ota_from_target_files.py
+++ b/tools/releasetools/test_ota_from_target_files.py
@@ -427,6 +427,7 @@
     common.OPTIONS.search_path = test_utils.get_search_path()
     self.assertIsNotNone(common.OPTIONS.search_path)
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_GetPackageMetadata_abOta_full(self):
     target_info_dict = copy.deepcopy(self.TEST_TARGET_INFO_DICT)
     target_info_dict['ab_update'] = 'true'
@@ -445,6 +446,7 @@
         },
         metadata)
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_GetPackageMetadata_abOta_incremental(self):
     target_info_dict = copy.deepcopy(self.TEST_TARGET_INFO_DICT)
     target_info_dict['ab_update'] = 'true'
@@ -467,6 +469,7 @@
         },
         metadata)
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_GetPackageMetadata_nonAbOta_full(self):
     target_info = BuildInfo(self.TEST_TARGET_INFO_DICT, None)
     metadata = GetPackageMetadata(target_info)
@@ -482,6 +485,7 @@
         },
         metadata)
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_GetPackageMetadata_nonAbOta_incremental(self):
     target_info = BuildInfo(self.TEST_TARGET_INFO_DICT, None)
     source_info = BuildInfo(self.TEST_SOURCE_INFO_DICT, None)
@@ -501,6 +505,7 @@
         },
         metadata)
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_GetPackageMetadata_wipe(self):
     target_info = BuildInfo(self.TEST_TARGET_INFO_DICT, None)
     common.OPTIONS.wipe_user_data = True
@@ -518,6 +523,7 @@
         },
         metadata)
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_GetPackageMetadata_retrofitDynamicPartitions(self):
     target_info = BuildInfo(self.TEST_TARGET_INFO_DICT, None)
     common.OPTIONS.retrofit_dynamic_partitions = True
@@ -542,6 +548,7 @@
          source_info['build.prop']['ro.build.date.utc'],
          target_info['build.prop']['ro.build.date.utc'])
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_GetPackageMetadata_unintentionalDowngradeDetected(self):
     target_info_dict = copy.deepcopy(self.TEST_TARGET_INFO_DICT)
     source_info_dict = copy.deepcopy(self.TEST_SOURCE_INFO_DICT)
@@ -554,6 +561,7 @@
     self.assertRaises(RuntimeError, GetPackageMetadata, target_info,
                       source_info)
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_GetPackageMetadata_downgrade(self):
     target_info_dict = copy.deepcopy(self.TEST_TARGET_INFO_DICT)
     source_info_dict = copy.deepcopy(self.TEST_SOURCE_INFO_DICT)
@@ -582,6 +590,7 @@
         },
         metadata)
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_GetTargetFilesZipForSecondaryImages(self):
     input_file = construct_target_files(secondary=True)
     target_file = GetTargetFilesZipForSecondaryImages(input_file)
@@ -600,6 +609,7 @@
     self.assertNotIn('IMAGES/system_other.img', namelist)
     self.assertNotIn('IMAGES/system.map', namelist)
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_GetTargetFilesZipForSecondaryImages_skipPostinstall(self):
     input_file = construct_target_files(secondary=True)
     target_file = GetTargetFilesZipForSecondaryImages(
@@ -619,6 +629,7 @@
     self.assertNotIn('IMAGES/system.map', namelist)
     self.assertNotIn(POSTINSTALL_CONFIG, namelist)
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_GetTargetFilesZipForSecondaryImages_withoutRadioImages(self):
     input_file = construct_target_files(secondary=True)
     common.ZipDelete(input_file, 'RADIO/bootloader.img')
@@ -639,12 +650,14 @@
     self.assertNotIn('RADIO/bootloader.img', namelist)
     self.assertNotIn('RADIO/modem.img', namelist)
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_GetTargetFilesZipWithoutPostinstallConfig(self):
     input_file = construct_target_files()
     target_file = GetTargetFilesZipWithoutPostinstallConfig(input_file)
     with zipfile.ZipFile(target_file) as verify_zip:
       self.assertNotIn(POSTINSTALL_CONFIG, verify_zip.namelist())
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_GetTargetFilesZipWithoutPostinstallConfig_missingEntry(self):
     input_file = construct_target_files()
     common.ZipDelete(input_file, POSTINSTALL_CONFIG)
@@ -675,20 +688,25 @@
     FinalizeMetadata(metadata, zip_file, output_file, needed_property_files)
     self.assertIn('ota-test-property-files', metadata)
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_FinalizeMetadata(self):
     self._test_FinalizeMetadata()
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_FinalizeMetadata_withNoSigning(self):
     common.OPTIONS.no_signing = True
     self._test_FinalizeMetadata()
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_FinalizeMetadata_largeEntry(self):
     self._test_FinalizeMetadata(large_entry=True)
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_FinalizeMetadata_largeEntry_withNoSigning(self):
     common.OPTIONS.no_signing = True
     self._test_FinalizeMetadata(large_entry=True)
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_FinalizeMetadata_insufficientSpace(self):
     entries = [
         'required-entry1',
@@ -766,6 +784,7 @@
           expected = entry.replace('.', '-').upper().encode()
         self.assertEqual(expected, input_fp.read(size))
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_Compute(self):
     entries = (
         'required-entry1',
@@ -805,6 +824,7 @@
     with zipfile.ZipFile(zip_file, 'r') as zip_fp:
       self.assertRaises(KeyError, property_files.Compute, zip_fp)
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_Finalize(self):
     entries = [
         'required-entry1',
@@ -825,6 +845,7 @@
     entries[2] = 'metadata'
     self._verify_entries(zip_file, tokens, entries)
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_Finalize_assertReservedLength(self):
     entries = (
         'required-entry1',
@@ -998,6 +1019,7 @@
         ),
         property_files.optional)
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_GetPayloadMetadataOffsetAndSize(self):
     target_file = construct_target_files()
     payload = Payload()
@@ -1071,6 +1093,7 @@
 
     return zip_file
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_Compute(self):
     zip_file = self.construct_zip_package_withValidPayload()
     property_files = AbOtaPropertyFiles()
@@ -1084,6 +1107,7 @@
     self._verify_entries(
         zip_file, tokens, ('care_map.txt', 'compatibility.zip'))
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_Finalize(self):
     zip_file = self.construct_zip_package_withValidPayload(with_metadata=True)
     property_files = AbOtaPropertyFiles()
@@ -1099,6 +1123,7 @@
     self._verify_entries(
         zip_file, tokens, ('care_map.txt', 'compatibility.zip'))
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_Verify(self):
     zip_file = self.construct_zip_package_withValidPayload(with_metadata=True)
     property_files = AbOtaPropertyFiles()
@@ -1204,6 +1229,7 @@
 
   def test_GetKeySizeInBytes_512Bytes(self):
     signing_key = os.path.join(self.testdata_dir, 'testkey_RSA4096.key')
+    # pylint: disable=protected-access
     key_size = PayloadSigner._GetKeySizeInBytes(signing_key)
     self.assertEqual(512, key_size)
 
@@ -1273,14 +1299,17 @@
     payload.Generate(target_file, source_file)
     return payload
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_Generate_full(self):
     payload = self._create_payload_full()
     self.assertTrue(os.path.exists(payload.payload_file))
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_Generate_incremental(self):
     payload = self._create_payload_incremental()
     self.assertTrue(os.path.exists(payload.payload_file))
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_Generate_additionalArgs(self):
     target_file = construct_target_files()
     source_file = construct_target_files()
@@ -1291,12 +1320,14 @@
         target_file, additional_args=["--source_image", source_file])
     self.assertTrue(os.path.exists(payload.payload_file))
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_Generate_invalidInput(self):
     target_file = construct_target_files()
     common.ZipDelete(target_file, 'IMAGES/vendor.img')
     payload = Payload()
     self.assertRaises(common.ExternalError, payload.Generate, target_file)
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_Sign_full(self):
     payload = self._create_payload_full()
     payload.Sign(PayloadSigner())
@@ -1310,6 +1341,7 @@
         os.path.join(self.testdata_dir, 'testkey.x509.pem'),
         output_file)
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_Sign_incremental(self):
     payload = self._create_payload_incremental()
     payload.Sign(PayloadSigner())
@@ -1323,6 +1355,7 @@
         os.path.join(self.testdata_dir, 'testkey.x509.pem'),
         output_file)
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_Sign_withDataWipe(self):
     common.OPTIONS.wipe_user_data = True
     payload = self._create_payload_full()
@@ -1331,6 +1364,7 @@
     with open(payload.payload_properties) as properties_fp:
       self.assertIn("POWERWASH=1", properties_fp.read())
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_Sign_secondary(self):
     payload = self._create_payload_full(secondary=True)
     payload.Sign(PayloadSigner())
@@ -1338,6 +1372,7 @@
     with open(payload.payload_properties) as properties_fp:
       self.assertIn("SWITCH_SLOT_ON_REBOOT=0", properties_fp.read())
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_Sign_badSigner(self):
     """Tests that signing failure can be captured."""
     payload = self._create_payload_full()
@@ -1345,6 +1380,7 @@
     payload_signer.signer_args.append('bad-option')
     self.assertRaises(common.ExternalError, payload.Sign, payload_signer)
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_WriteToZip(self):
     payload = self._create_payload_full()
     payload.Sign(PayloadSigner())
@@ -1366,6 +1402,7 @@
           continue
         self.assertEqual(zipfile.ZIP_STORED, entry_info.compress_type)
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_WriteToZip_unsignedPayload(self):
     """Unsigned payloads should not be allowed to be written to zip."""
     payload = self._create_payload_full()
@@ -1381,6 +1418,7 @@
     with zipfile.ZipFile(output_file, 'w') as output_zip:
       self.assertRaises(AssertionError, payload.WriteToZip, output_zip)
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_WriteToZip_secondary(self):
     payload = self._create_payload_full(secondary=True)
     payload.Sign(PayloadSigner())
diff --git a/tools/releasetools/test_utils.py b/tools/releasetools/test_utils.py
index ca127b1..1e919f7 100755
--- a/tools/releasetools/test_utils.py
+++ b/tools/releasetools/test_utils.py
@@ -31,6 +31,18 @@
 # Some test runner doesn't like outputs from stderr.
 logging.basicConfig(stream=sys.stdout)
 
+# Use ANDROID_BUILD_TOP as an indicator to tell if the needed tools (e.g.
+# avbtool, mke2fs) are available while running the tests. Not having the var or
+# having empty string means we can't run the tests that require external tools.
+EXTERNAL_TOOLS_UNAVAILABLE = not os.environ.get("ANDROID_BUILD_TOP")
+
+
+def SkipIfExternalToolsUnavailable():
+  """Decorator function that allows skipping tests per tools availability."""
+  if EXTERNAL_TOOLS_UNAVAILABLE:
+    return unittest.skip('External tools unavailable')
+  return lambda func: func
+
 
 def get_testdata_dir():
   """Returns the testdata dir, in relative to the script dir."""
diff --git a/tools/releasetools/test_validate_target_files.py b/tools/releasetools/test_validate_target_files.py
index 5f619ec..70e3b49 100644
--- a/tools/releasetools/test_validate_target_files.py
+++ b/tools/releasetools/test_validate_target_files.py
@@ -55,6 +55,7 @@
         0, proc.returncode,
         "Failed to sign boot image with boot_signer: {}".format(stdoutdata))
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_ValidateVerifiedBootImages_bootImage(self):
     input_tmp = common.MakeTempDir()
     os.mkdir(os.path.join(input_tmp, 'IMAGES'))
@@ -69,6 +70,7 @@
     }
     ValidateVerifiedBootImages(input_tmp, info_dict, options)
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_ValidateVerifiedBootImages_bootImage_wrongKey(self):
     input_tmp = common.MakeTempDir()
     os.mkdir(os.path.join(input_tmp, 'IMAGES'))
@@ -85,6 +87,7 @@
         AssertionError, ValidateVerifiedBootImages, input_tmp, info_dict,
         options)
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_ValidateVerifiedBootImages_bootImage_corrupted(self):
     input_tmp = common.MakeTempDir()
     os.mkdir(os.path.join(input_tmp, 'IMAGES'))
@@ -139,6 +142,7 @@
     # Append the verity metadata.
     verity_image_builder.Build(output_file)
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_ValidateVerifiedBootImages_systemImage(self):
     input_tmp = common.MakeTempDir()
     os.mkdir(os.path.join(input_tmp, 'IMAGES'))
@@ -162,6 +166,7 @@
     }
     ValidateVerifiedBootImages(input_tmp, info_dict, options)
 
+  @test_utils.SkipIfExternalToolsUnavailable()
   def test_ValidateFileConsistency_incompleteRange(self):
     input_tmp = common.MakeTempDir()
     os.mkdir(os.path.join(input_tmp, 'IMAGES'))
diff --git a/tools/releasetools/test_verity_utils.py b/tools/releasetools/test_verity_utils.py
index e0607c8..1cc539f 100644
--- a/tools/releasetools/test_verity_utils.py
+++ b/tools/releasetools/test_verity_utils.py
@@ -24,7 +24,8 @@
 import common
 import sparse_img
 from rangelib import RangeSet
-from test_utils import get_testdata_dir, ReleaseToolsTestCase
+from test_utils import (
+    get_testdata_dir, ReleaseToolsTestCase, SkipIfExternalToolsUnavailable)
 from verity_utils import (
     CreateHashtreeInfoGenerator, CreateVerityImageBuilder, HashtreeInfo,
     VerifiedBootVersion1HashtreeInfoGenerator)
@@ -89,6 +90,7 @@
 
     return output_file
 
+  @SkipIfExternalToolsUnavailable()
   def test_CreateHashtreeInfoGenerator(self):
     image_file = sparse_img.SparseImage(self._generate_image())
 
@@ -99,6 +101,7 @@
     self.assertEqual(self.partition_size, generator.partition_size)
     self.assertTrue(generator.fec_supported)
 
+  @SkipIfExternalToolsUnavailable()
   def test_DecomposeSparseImage(self):
     image_file = sparse_img.SparseImage(self._generate_image())
 
@@ -109,6 +112,7 @@
     self.assertEqual(12288, generator.hashtree_size)
     self.assertEqual(32768, generator.metadata_size)
 
+  @SkipIfExternalToolsUnavailable()
   def test_ParseHashtreeMetadata(self):
     image_file = sparse_img.SparseImage(self._generate_image())
     generator = VerifiedBootVersion1HashtreeInfoGenerator(
@@ -123,6 +127,7 @@
     self.assertEqual(self.fixed_salt, generator.hashtree_info.salt)
     self.assertEqual(self.expected_root_hash, generator.hashtree_info.root_hash)
 
+  @SkipIfExternalToolsUnavailable()
   def test_ValidateHashtree_smoke(self):
     generator = VerifiedBootVersion1HashtreeInfoGenerator(
         self.partition_size, 4096, True)
@@ -138,6 +143,7 @@
 
     self.assertTrue(generator.ValidateHashtree())
 
+  @SkipIfExternalToolsUnavailable()
   def test_ValidateHashtree_failure(self):
     generator = VerifiedBootVersion1HashtreeInfoGenerator(
         self.partition_size, 4096, True)
@@ -153,6 +159,7 @@
 
     self.assertFalse(generator.ValidateHashtree())
 
+  @SkipIfExternalToolsUnavailable()
   def test_Generate(self):
     image_file = sparse_img.SparseImage(self._generate_image())
     generator = CreateHashtreeInfoGenerator('system', 4096, self.prop_dict)
@@ -193,6 +200,7 @@
     del prop_dict['verity_block_device']
     self.assertIsNone(CreateVerityImageBuilder(prop_dict))
 
+  @SkipIfExternalToolsUnavailable()
   def test_CalculateMaxImageSize(self):
     verity_image_builder = CreateVerityImageBuilder(self.DEFAULT_PROP_DICT)
     size = verity_image_builder.CalculateMaxImageSize()
@@ -221,11 +229,13 @@
     cmd = ['verity_verifier', image, '-mincrypt', verify_key]
     common.RunAndCheckOutput(cmd)
 
+  @SkipIfExternalToolsUnavailable()
   def test_Build(self):
     self._BuildAndVerify(
         self.DEFAULT_PROP_DICT,
         os.path.join(get_testdata_dir(), 'testkey_mincrypt'))
 
+  @SkipIfExternalToolsUnavailable()
   def test_Build_SanityCheck(self):
     # A sanity check for the test itself: the image shouldn't be verifiable
     # with wrong key.
@@ -235,6 +245,7 @@
         self.DEFAULT_PROP_DICT,
         os.path.join(get_testdata_dir(), 'verity_mincrypt'))
 
+  @SkipIfExternalToolsUnavailable()
   def test_Build_FecDisabled(self):
     prop_dict = copy.deepcopy(self.DEFAULT_PROP_DICT)
     del prop_dict['verity_fec']
@@ -242,6 +253,7 @@
         prop_dict,
         os.path.join(get_testdata_dir(), 'testkey_mincrypt'))
 
+  @SkipIfExternalToolsUnavailable()
   def test_Build_SquashFs(self):
     verity_image_builder = CreateVerityImageBuilder(self.DEFAULT_PROP_DICT)
     verity_image_builder.CalculateMaxImageSize()
@@ -282,6 +294,7 @@
     verity_image_builder = CreateVerityImageBuilder(prop_dict)
     self.assertIsNone(verity_image_builder)
 
+  @SkipIfExternalToolsUnavailable()
   def test_Build(self):
     prop_dict = copy.deepcopy(self.DEFAULT_PROP_DICT)
     verity_image_builder = CreateVerityImageBuilder(prop_dict)