add tests

tests/api.py

@@ -0,0 +1,19 @@
+import unittest
+import os.path
+
+import rfc3161
+
+class Rfc3161(unittest.TestCase):
+    PUBLIC_TSA_SERVER = 'http://time.certum.pl'
+    CERTIFICATE = os.path.join(os.path.dirname(__file__),
+            '../data/certum_certificate.crt')
+
+    def test_timestamp(self):
+        try:
+            certificate = file(self.CERTIFICATE).read()
+            value, substrate = rfc3161.RemoteTimestamper(
+                    self.PUBLIC_TSA_SERVER, certificate=certificate)(data='xx')
+        except rfc3161.TimestampingError:
+            return
+        self.assertNotEqual(value, None)
+        self.assertEqual(substrate, '')