WIP test_accessor: write into copy file as binary

This works properly for the http case, but FileAccessor provides us with
a text fileobj handle, and `read()` gets a UTF-8 decoding error.

FIXME: Accessor ctor requires a `mode` argument

Author: ydirson

tests/test_accessor.py

@@ -23,8 +23,12 @@ def test_file_binfile(self):
         a.start()
         self.assertTrue(a.access(BINFILE))
         inf = a.openAddress(BINFILE)
-        with NamedTemporaryFile("w") as outf:
-            outf.writelines(inf)
+        with NamedTemporaryFile("wb") as outf:
+            while True:
+                data = inf.read()
+                if not data: # EOF
+                    break
+                outf.write(data)
             outf.flush()
             hasher = hashlib.md5()
             with open(outf.name, "rb") as bincontents: