From: Michael Foord <michael@voidspace.org.uk>
Date: Sun, 25 Mar 2012 18:03:13 +0000 (+0100)
Subject: unittest.mock: set file_spec on first use
X-Git-Tag: v3.3.0a2~61
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=a74561a56d58187ebfdad25104486bbcd08e1de6;p=python

unittest.mock: set file_spec on first use
---

diff --git a/Lib/unittest/mock.py b/Lib/unittest/mock.py
index 9a0bbf0fe3..6ecc4c71f6 100644
--- a/Lib/unittest/mock.py
+++ b/Lib/unittest/mock.py
@@ -2138,11 +2138,15 @@ FunctionAttributes = set([
     'func_name',
 ])
 
-import _io
-file_spec = list(set(dir(_io.TextIOWrapper)).union(set(dir(_io.BytesIO))))
 
+file_spec = None
 
 def mock_open(mock=None, read_data=None):
+    global file_spec
+    if file_spec is None:
+        import _io
+        file_spec = list(set(dir(_io.TextIOWrapper)).union(set(dir(_io.BytesIO))))
+
     if mock is None:
         mock = MagicMock(spec=file_spec)