use buffer as variable name for bytearray objects

Author: nwh

fs/memoryfs.py

@@ -140,13 +140,13 @@ def readable(self):
         # type: () -> bool
         return self._mode.reading
 
-    def readinto(self, b):
+    def readinto(self, buffer):
         # type (bytearray) -> Optional[int]
         if not self._mode.reading:
             raise IOError("File not open for reading")
         with self._seek_lock():
             self.on_access()
-            return self._bytes_io.readinto(b)
+            return self._bytes_io.readinto(buffer)
 
     def readlines(self, hint=-1):
         # type: (int) -> List[bytes]

fs/test.py

@@ -869,10 +869,10 @@ def test_open_files(self):
             self.assertFalse(f.closed)
             self.assertEqual(f.readlines(8), [b"Hello\n", b"World\n"])
             self.assertEqual(f.tell(), 12)
-            b = bytearray(4)
-            self.assertEqual(f.readinto(b), 4)
+            buffer = bytearray(4)
+            self.assertEqual(f.readinto(buffer), 4)
             self.assertEqual(f.tell(), 16)
-            self.assertEqual(b, b"foo\n")
+            self.assertEqual(buffer, b"foo\n")
             with self.assertRaises(IOError):
                 f.write(b"no")
         self.assertTrue(f.closed)