1 files changed, 20 insertions, 1 deletions
diff --git a/tests/hazmat/primitives/test_ciphers.py b/tests/hazmat/primitives/test_ciphers.py
index dfafab3f..653f7ce6 100644
--- a/tests/hazmat/primitives/test_ciphers.py
+++ b/tests/hazmat/primitives/test_ciphers.py
@@ -18,7 +18,7 @@ import binascii
 import pytest
 
 from cryptography.hazmat.primitives.ciphers.algorithms import (
-    AES, Camellia, TripleDES, Blowfish, CAST5
+    AES, Camellia, TripleDES, Blowfish, CAST5, ARC4
 )
 
 
@@ -91,3 +91,22 @@ class TestCAST5(object):
     def test_invalid_key_size(self):
         with pytest.raises(ValueError):
             CAST5(binascii.unhexlify(b"0" * 34))
+
+
+class TestARC4(object):
+    @pytest.mark.parametrize(("key", "keysize"), [
+        (b"0" * 10, 40),
+        (b"0" * 14, 56),
+        (b"0" * 16, 64),
+        (b"0" * 20, 80),
+        (b"0" * 32, 128),
+        (b"0" * 48, 192),
+        (b"0" * 64, 256),
+    ])
+    def test_key_size(self, key, keysize):
+        cipher = ARC4(binascii.unhexlify(key))
+        assert cipher.key_size == keysize
+
+    def test_invalid_key_size(self):
+        with pytest.raises(ValueError):
+            ARC4(binascii.unhexlify(b"0" * 34))