espsecure digest_secure_bootloader: Fix Python 3 string vs bytes usage

Closes #382

.travis.yml

@@ -43,6 +43,7 @@ script:
   # doesn't allow running esptool.py as a script...
   - pip install pyserial pyelftools
   - python test/test_imagegen.py
+  - python test/test_espsecure.py
   - pip install flake8 flake8-future-import  # matches tests_require in setup.py, a bit hacky
   - python setup.py flake8
   - python setup.py install

espsecure.py

@@ -91,7 +91,7 @@ def digest_secure_bootloader(args):
     # if image isn't 128 byte multiple then pad with 0xFF (ie unwritten flash)
     # as this is what the secure boot engine will see
     if len(plaintext_image) % 128 != 0:
-        plaintext_image += "\xFF" * (128 - (len(plaintext_image) % 128))
+        plaintext_image += b"\xFF" * (128 - (len(plaintext_image) % 128))
 
     plaintext = iv + plaintext_image
 

test/secure_images/256bit_iv.bin

@@ -0,0 +1 @@
+EV8z"� �%�F�+�xk��)~�k�7JI��G>

test/secure_images/256bit_key.bin

@@ -0,0 +1 @@
+�>\'*���8%��q+�8��Lm*�E����

test/test_espsecure.py

@@ -0,0 +1,78 @@
+#!/usr/bin/env python
+#
+# Tests for espsecure.py
+#
+# Assumes openssl binary is in the PATH
+import unittest
+import subprocess
+import os
+import os.path
+import io
+import sys
+import tempfile
+from collections import namedtuple
+
+TEST_DIR = os.path.abspath(os.path.dirname(__file__))
+os.chdir(TEST_DIR)
+
+try:
+    import espsecure
+except ImportError:
+    sys.path.insert(0, os.path.join(TEST_DIR, ".."))
+    import espsecure
+
+import esptool
+
+class EspSecureTestCase(unittest.TestCase):
+
+    def run_espsecure(self, args):
+        """ Run espsecure.py with the specified arguments
+
+        Returns output as a string if there is any, raises an exception if espsecure.py fails
+        """
+        cmd = [sys.executable, ESPSECURE_PY ] + args.split(" ")
+        print("Running %s..." % (" ".join(cmd)))
+
+        try:
+            output = subprocess.check_output([str(s) for s in cmd],
+                                             cwd=TEST_DIR,
+                                             stderr=subprocess.STDOUT)
+            print(output)
+            return output.decode("utf-8")
+        except subprocess.CalledProcessError as e:
+            print(e.output)
+            raise e
+
+def _open(image_file):
+    return open(os.path.join('secure_images', image_file), 'rb')
+
+class SecureBootloaderTests(unittest.TestCase):
+
+    def test_digest_bootloader(self):
+        DBArgs = namedtuple('digest_bootloader_args', [
+            'keyfile',
+            'output',
+            'iv',
+            'image' ])
+
+        try:
+            output_file = tempfile.NamedTemporaryFile(delete=False)
+            output_file.close()
+
+            args = DBArgs(_open('256bit_key.bin'),
+                          output_file.name,
+                          _open('256bit_iv.bin'),
+                          _open('bootloader.bin'))
+            espsecure.digest_secure_bootloader(args)
+
+            with open(output_file.name, 'rb') as of:
+                with _open('bootloader_digested.bin') as ef:
+                    self.assertEqual(ef.read(), of.read())
+        finally:
+            os.unlink(output_file.name)
+
+
+if __name__ == '__main__':
+    print("Running espsecure tests...")
+    print("Using espsecure %s at %s" % (esptool.__version__, os.path.abspath(espsecure.__file__)))
+    unittest.main(buffer=True)