make create_modulename private, add test

1 files changed, 8 insertions, 4 deletions

diff --git a/cryptography/hazmat/bindings/utils.py b/cryptography/hazmat/bindings/utils.py
index 1d07cd97..3da0412e 100644
--- a/cryptography/hazmat/bindings/utils.py
+++ b/cryptography/hazmat/bindings/utils.py
@@ -71,7 +71,11 @@ def build_ffi(module_prefix, modules, pre_include, post_include, libraries):
     )
     lib = ffi.verify(
         source=source,
-        modulename=create_modulename(ffi, source),
+        modulename=_create_modulename(
+            ffi, source,
+            sys.version,
+            sys.version_info
+        ),
         libraries=libraries,
         ext_package="cryptography",
     )
@@ -87,7 +91,7 @@ def build_ffi(module_prefix, modules, pre_include, post_include, libraries):
     return ffi, lib
 
 
-def create_modulename(ffi, source):
+def _create_modulename(ffi, source, sys_version, sys_version_info):
     """
     cffi creates a modulename internally that incorporates the cffi version.
     This will cause cryptography's wheels to break when the version of cffi
@@ -95,8 +99,8 @@ def create_modulename(ffi, source):
     resolve this we build our own modulename that uses most of the same code
     from cffi but elides the version key.
     """
-    key = '\x00'.join([sys.version[:3], source] + ffi._cdefsources)
-    if sys.version_info >= (3,):
+    key = '\x00'.join([sys_version[:3], source] + ffi._cdefsources)
+    if sys_version_info >= (3,):
         key = key.encode('utf-8')
     k1 = hex(binascii.crc32(key[0::2]) & 0xffffffff)
     k1 = k1.lstrip('0x').rstrip('L')