releasetools: Add PayloadSigner class.

Create a wrapper class that handles the payload signing, which unifies
the paths with and without external signer. Also add tests for the newly
added class.

The test keys under testdata/ are created with the script in
development/tools/make_key. testdata/testkey_with_passwd.pk8 uses
password "foo".

Test: python -m unittest test_ota_from_target_files
Test: Get identical A/B OTA packages w/ and w/o the CL.
Change-Id: Ic770aec726498a3babb88ec509985e7f1210fb18

tools/releasetools/test_ota_from_target_files.py

@@ -15,11 +15,20 @@
 #
 
 import copy
+import os.path
 import unittest
 
 import common
 from ota_from_target_files import (
-    _LoadOemDicts, BuildInfo, GetPackageMetadata, WriteFingerprintAssertion)
+    _LoadOemDicts, BuildInfo, GetPackageMetadata, PayloadSigner,
+    WriteFingerprintAssertion)
+
+
+def get_testdata_dir():
+  """Returns the testdata dir, in relative to the script dir."""
+  # The script dir is the one we want, which could be different from pwd.
+  current_dir = os.path.dirname(os.path.realpath(__file__))
+  return os.path.join(current_dir, 'testdata')
 
 
 class MockScriptWriter(object):
@@ -476,3 +485,82 @@ class OtaFromTargetFilesTest(unittest.TestCase):
             'pre-build-incremental' : 'build-version-incremental-source',
         },
         metadata)
+
+
+class PayloadSignerTest(unittest.TestCase):
+
+  SIGFILE = 'sigfile.bin'
+  SIGNED_SIGFILE = 'signed-sigfile.bin'
+
+  def setUp(self):
+    self.testdata_dir = get_testdata_dir()
+    self.assertTrue(os.path.exists(self.testdata_dir))
+
+    common.OPTIONS.payload_signer = None
+    common.OPTIONS.payload_signer_args = []
+    common.OPTIONS.package_key = os.path.join(self.testdata_dir, 'testkey')
+    common.OPTIONS.key_passwords = {
+        common.OPTIONS.package_key : None,
+    }
+
+  def tearDown(self):
+    common.Cleanup()
+
+  def _assertFilesEqual(self, file1, file2):
+    with open(file1, 'rb') as fp1, open(file2, 'rb') as fp2:
+      self.assertEqual(fp1.read(), fp2.read())
+
+  def test_init(self):
+    payload_signer = PayloadSigner()
+    self.assertEqual('openssl', payload_signer.signer)
+
+  def test_init_withPassword(self):
+    common.OPTIONS.package_key = os.path.join(
+        self.testdata_dir, 'testkey_with_passwd')
+    common.OPTIONS.key_passwords = {
+        common.OPTIONS.package_key : 'foo',
+    }
+    payload_signer = PayloadSigner()
+    self.assertEqual('openssl', payload_signer.signer)
+
+  def test_init_withExternalSigner(self):
+    common.OPTIONS.payload_signer = 'abc'
+    common.OPTIONS.payload_signer_args = ['arg1', 'arg2']
+    payload_signer = PayloadSigner()
+    self.assertEqual('abc', payload_signer.signer)
+    self.assertEqual(['arg1', 'arg2'], payload_signer.signer_args)
+
+  def test_Sign(self):
+    payload_signer = PayloadSigner()
+    input_file = os.path.join(self.testdata_dir, self.SIGFILE)
+    signed_file = payload_signer.Sign(input_file)
+
+    verify_file = os.path.join(self.testdata_dir, self.SIGNED_SIGFILE)
+    self._assertFilesEqual(verify_file, signed_file)
+
+  def test_Sign_withExternalSigner_openssl(self):
+    """Uses openssl as the external payload signer."""
+    common.OPTIONS.payload_signer = 'openssl'
+    common.OPTIONS.payload_signer_args = [
+        'pkeyutl', '-sign', '-keyform', 'DER', '-inkey',
+        os.path.join(self.testdata_dir, 'testkey.pk8'),
+        '-pkeyopt', 'digest:sha256']
+    payload_signer = PayloadSigner()
+    input_file = os.path.join(self.testdata_dir, self.SIGFILE)
+    signed_file = payload_signer.Sign(input_file)
+
+    verify_file = os.path.join(self.testdata_dir, self.SIGNED_SIGFILE)
+    self._assertFilesEqual(verify_file, signed_file)
+
+  def test_Sign_withExternalSigner_script(self):
+    """Uses testdata/payload_signer.sh as the external payload signer."""
+    common.OPTIONS.payload_signer = os.path.join(
+        self.testdata_dir, 'payload_signer.sh')
+    common.OPTIONS.payload_signer_args = [
+        os.path.join(self.testdata_dir, 'testkey.pk8')]
+    payload_signer = PayloadSigner()
+    input_file = os.path.join(self.testdata_dir, self.SIGFILE)
+    signed_file = payload_signer.Sign(input_file)
+
+    verify_file = os.path.join(self.testdata_dir, self.SIGNED_SIGFILE)
+    self._assertFilesEqual(verify_file, signed_file)