Fixes pyca#4076 - simplify the implementation of int_from_bytes on python2 (pyca#4077)

* Fixes pyca#4076 - simplify the implementation of int_from_bytes on python2

* whitespace

* Added a test

Author: alex

src/cryptography/utils.py

@@ -57,8 +57,7 @@ def int_from_bytes(data, byteorder, signed=False):
         assert byteorder == 'big'
         assert not signed
 
-        # call bytes() on data to allow the use of bytearrays
-        return int(bytes(data).encode('hex'), 16)
+        return int(binascii.hexlify(data), 16)
 
 
 if hasattr(int, "to_bytes"):

tests/test_cryptography_utils.py

@@ -11,6 +11,8 @@
 
 def test_int_from_bytes_bytearray():
     assert utils.int_from_bytes(bytearray(b"\x02\x10"), "big") == 528
+    with pytest.raises(TypeError):
+        utils.int_from_bytes(["list", "is", "not", "bytes"], "big")
 
 
 class TestCachedProperty(object):