util: Factor readfile function into here

Soon we will need to use it not only from test_restore.py

zodbtools/test/test_restore.py

@@ -21,7 +21,7 @@
 from __future__ import print_function
 
 from zodbtools.zodbrestore import zodbrestore
-from zodbtools.util import storageFromURL
+from zodbtools.util import storageFromURL, readfile
 
 from os.path import dirname
 from tempfile import mkdtemp
@@ -49,12 +49,6 @@ def test_zodbrestore(zext):
         zodbrestore(stor, zdump)
     _()
 
-    zfs1 = _readfile("%s/1%s.fs" % (tdata, zkind))
-    zfs2 = _readfile("%s/2.fs" % tmpd)
+    zfs1 = readfile("%s/1%s.fs" % (tdata, zkind))
+    zfs2 = readfile("%s/2.fs" % tmpd)
     assert zfs1 == zfs2
-
-
-# _readfile reads file at path.
-def _readfile(path): # -> data(bytes)
-    with open(path, 'rb') as _:
-        return _.read()

zodbtools/util.py

 # -*- coding: utf-8 -*-
 # zodbtools - various utility routines
-# Copyright (C) 2016-2019  Nexedi SA and Contributors.
+# Copyright (C) 2016-2022  Nexedi SA and Contributors.
 #                          Kirill Smelkov <kirr@nexedi.com>
 #                          Jérome Perrin <jerome@nexedi.com>
 #
@@ -235,3 +235,9 @@ def asbinstream(stream):
     if isinstance(stream, io.TextIOBase):
         return stream.buffer
     return stream
+
+
+# readfile reads file at path.
+def readfile(path): # -> data(bytes)
+    with open(path, 'rb') as _:
+        return _.read()