Add tests for GPGSigner

Test all variations of the GPG schema securesystemslib curretnly
supports. Make sure we can easly sign, receive an object from the sign
operation and use the information stored from that object to verify
the signature.

Signed-off-by: Martin Vrachev <[email protected]>

tests/test_signer.py

@@ -3,14 +3,20 @@
 """Test cases for "signer.py". """
 
 import copy
-import sys
+import os
 import unittest
+import tempfile
+import shutil
 
-import unittest
 import securesystemslib.formats
 import securesystemslib.keys as KEYS
 from securesystemslib.exceptions import FormatError, UnsupportedAlgorithmError
-from securesystemslib.signer import Signature, SSlibSigner
+from securesystemslib.signer import Signature, SSlibSigner, GPGSigner
+from securesystemslib.gpg.constants import HAVE_GPG
+from securesystemslib.gpg.functions import (
+    export_pubkey,
+    verify_signature as verify_sig
+)
 
 
 class TestSSlibSigner(unittest.TestCase):
@@ -91,6 +97,63 @@ def test_signature_eq_(self):
         sig_obj_2 = None
         self.assertNotEqual(sig_obj, sig_obj_2)
 
+@unittest.skipIf(not HAVE_GPG, "gpg not found")
+class TestGPGRSA(unittest.TestCase):
+    """Test RSA gpg signature creation and verification."""
+
+    @classmethod
+    def setUpClass(cls):
+        cls.default_keyid = "8465A1E2E0FB2B40ADB2478E18FB3F537E0C8A17"
+        cls.signing_subkey_keyid = "C5A0ABE6EC19D0D65F85E2C39BE9DF5131D924E9"
+
+        # Create directory to run the tests without having everything blow up.
+        cls.working_dir = os.getcwd()
+        cls.test_data = b'test_data'
+        cls.wrong_data = b'something malicious'
+
+        # Find demo files.
+        gpg_keyring_path = os.path.join(
+            os.path.dirname(os.path.realpath(__file__)), "gpg_keyrings", "rsa")
+
+        cls.test_dir = os.path.realpath(tempfile.mkdtemp())
+        cls.gnupg_home = os.path.join(cls.test_dir, "rsa")
+        shutil.copytree(gpg_keyring_path, cls.gnupg_home)
+        os.chdir(cls.test_dir)
+
+
+    @classmethod
+    def tearDownClass(cls):
+        """Change back to initial working dir and remove temp test directory."""
+
+        os.chdir(cls.working_dir)
+        shutil.rmtree(cls.test_dir)
+
+
+    def test_gpg_sign_and_verify_object_with_default_key(self):
+        """Create a signature using the default key on the keyring. """
+
+        signer = GPGSigner(homedir=self.gnupg_home)
+        signature = signer.sign(self.test_data)
+
+        signature_dict = signature.to_dict()
+        key_data = export_pubkey(self.default_keyid, self.gnupg_home)
+
+        self.assertTrue(verify_sig(signature_dict, key_data, self.test_data))
+        self.assertFalse(verify_sig(signature_dict, key_data, self.wrong_data))
+
+
+    def test_gpg_sign_and_verify_object(self):
+        """Create a signature using a specific key on the keyring. """
+
+        signer = GPGSigner(self.signing_subkey_keyid, self.gnupg_home)
+        signature = signer.sign(self.test_data)
+
+        signature_dict = signature.to_dict()
+        key_data = export_pubkey(self.signing_subkey_keyid, self.gnupg_home)
+
+        self.assertTrue(verify_sig(signature_dict, key_data, self.test_data))
+        self.assertFalse(verify_sig(signature_dict, key_data, self.wrong_data))
+
 
 # Run the unit tests.
 if __name__ == "__main__":