3 files changed, 88 insertions, 0 deletions
diff --git a/tests/hazmat/bindings/test_openssl.py b/tests/hazmat/bindings/test_openssl.py
index 35eb7e8d..c476390b 100644
--- a/tests/hazmat/bindings/test_openssl.py
+++ b/tests/hazmat/bindings/test_openssl.py
@@ -96,3 +96,8 @@ class TestOpenSSL(object):
         # unlocked
         assert lock.acquire(False)
         lock.release()
+
+    def test_add_engine_more_than_once(self):
+        b = Binding()
+        res = b.lib.Cryptography_add_osrandom_engine()
+        assert res == 2
diff --git a/tests/hazmat/primitives/twofactor/__init__.py b/tests/hazmat/primitives/twofactor/__init__.py
new file mode 100644
index 00000000..e69de29b
--- /dev/null
+++ b/tests/hazmat/primitives/twofactor/__init__.py
diff --git a/tests/hazmat/primitives/twofactor/test_hotp.py b/tests/hazmat/primitives/twofactor/test_hotp.py
new file mode 100644
index 00000000..ec619b55
--- /dev/null
+++ b/tests/hazmat/primitives/twofactor/test_hotp.py
@@ -0,0 +1,83 @@
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+# implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import os
+
+import pytest
+
+from cryptography.exceptions import InvalidToken
+from cryptography.hazmat.primitives.twofactor.hotp import HOTP
+from cryptography.hazmat.primitives import hashes
+from tests.utils import load_vectors_from_file, load_nist_vectors
+
+vectors = load_vectors_from_file(
+    "twofactor/rfc-4226.txt", load_nist_vectors)
+
+
+@pytest.mark.supported(
+    only_if=lambda backend: backend.hmac_supported(hashes.SHA1()),
+    skip_message="Does not support HMAC-SHA1."
+)
+@pytest.mark.hmac
+class TestHOTP(object):
+
+    def test_invalid_key_length(self, backend):
+        secret = os.urandom(10)
+
+        with pytest.raises(ValueError):
+            HOTP(secret, 6, backend)
+
+    def test_invalid_hotp_length(self, backend):
+        secret = os.urandom(16)
+
+        with pytest.raises(ValueError):
+            HOTP(secret, 4, backend)
+
+    @pytest.mark.parametrize("params", vectors)
+    def test_truncate(self, backend, params):
+        secret = params["secret"]
+        counter = int(params["counter"])
+        truncated = params["truncated"]
+
+        hotp = HOTP(secret, 6, backend)
+
+        assert hotp._dynamic_truncate(counter) == int(truncated.decode(), 16)
+
+    @pytest.mark.parametrize("params", vectors)
+    def test_generate(self, backend, params):
+        secret = params["secret"]
+        counter = int(params["counter"])
+        hotp_value = params["hotp"]
+
+        hotp = HOTP(secret, 6, backend)
+
+        assert hotp.generate(counter) == hotp_value
+
+    @pytest.mark.parametrize("params", vectors)
+    def test_verify(self, backend, params):
+        secret = params["secret"]
+        counter = int(params["counter"])
+        hotp_value = params["hotp"]
+
+        hotp = HOTP(secret, 6, backend)
+
+        assert hotp.verify(hotp_value, counter) is None
+
+    def test_invalid_verify(self, backend):
+        secret = b"12345678901234567890"
+        counter = 0
+
+        hotp = HOTP(secret, 6, backend)
+
+        with pytest.raises(InvalidToken):
+            hotp.verify(b"123456", counter)