[test] ciphertext size function tests

tests/client/test_crypto.py

@@ -126,6 +126,19 @@ class BlobTestCase(unittest.TestCase):
         decrypted = yield decryptor.decrypt()
         assert decrypted.getvalue() == snowden1
 
+    @defer.inlineCallbacks
+    def test_get_unarmored_ciphertext_size(self):
+        for size_to_test in xrange(-1, 400):
+            test_content = '\x00' * size_to_test
+            size = _crypto.get_unarmored_ciphertext_size(len(test_content))
+            inf = BytesIO(test_content)
+            blob = _crypto.BlobEncryptor(
+                self.doc_info, inf,
+                armor=False,
+                secret='A' * 96)
+            encrypted = yield blob.encrypt()
+            assert len(encrypted.getvalue()) == size, size_to_test
+
     @defer.inlineCallbacks
     def test_default_armored_blob_encrypt(self):
         encrypted = yield self.blob.encrypt()