diff --git a/cryptography/fernet.py b/cryptography/fernet.py
index 2c134bb..ef747b7 100644
--- a/cryptography/fernet.py
+++ b/cryptography/fernet.py
@@ -37,8 +37,10 @@
             b"\x80" + struct.pack(">Q", current_time) + iv + ciphertext + hmac
         )
 
-    def decrypt(self, data, ttl=None):
+    def decrypt(self, data, ttl=None, current_time=None):
         # TODO: whole function is a giant hack job with no error checking
+        if current_time is None:
+            current_time = int(time.time())
         data = base64.urlsafe_b64decode(data)
         assert data[0] == b"\x80"
         timestamp = data[1:9]
@@ -46,7 +48,7 @@
         ciphertext = data[25:-32]
         hmac = data[-32:]
         if ttl is not None:
-            if struct.unpack(">Q", timestamp)[0] + ttl > int(time.time()):
+            if struct.unpack(">Q", timestamp)[0] + ttl < current_time:
                 raise ValueError
         h = HMAC(self.signing_key, digestmod=hashes.SHA256)
         h.update(data[:-32])
diff --git a/tests/test_fernet.py b/tests/test_fernet.py
index e9d07f8..f7c06b9 100644
--- a/tests/test_fernet.py
+++ b/tests/test_fernet.py
@@ -13,11 +13,17 @@
             499162800,
             b"\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0A\x0B\x0C\x0D\x0E\x0F",
         )
-        assert token == b"gAAAAAAdwJ6wAAECAwQFBgcICQoLDA0ODy021cpGVWKZ_eEwCGM4BLLF_5CV9dOPmrhuVUPgJobwOz7JcbmrR64jVmpU4IwqDA=="
+        assert token == (b"gAAAAAAdwJ6wAAECAwQFBgcICQoLDA0ODy021cpGVWKZ_eEwCGM"
+                          "4BLLF_5CV9dOPmrhuVUPgJobwOz7JcbmrR64jVmpU4IwqDA==")
 
     def test_verify(self):
         f = Fernet(base64.urlsafe_b64decode(
             b"cw_0x689RpI-jtRR7oE8h_eQsKImvJapLeSbXpwF4e4="
         ))
-        payload = f.decrypt(b"gAAAAAAdwJ6wAAECAwQFBgcICQoLDA0ODy021cpGVWKZ_eEwCGM4BLLF_5CV9dOPmrhuVUPgJobwOz7JcbmrR64jVmpU4IwqDA==", 60)
+        payload = f.decrypt(
+            (b"gAAAAAAdwJ6wAAECAwQFBgcICQoLDA0ODy021cpGVWKZ_eEwCGM4BLLF_5CV9dO"
+              "PmrhuVUPgJobwOz7JcbmrR64jVmpU4IwqDA=="),
+            ttl=60,
+            current_time=499162801
+        )
         assert payload == b"hello"