Fix free-threading test

Author: marcelm

Lib/test/test_free_threading/test_io.py

@@ -67,9 +67,9 @@ def readinto(barrier, b, into, *ignore):
             barrier.wait()
             b.readinto(into)
 
-        def peek(barrier, b, into, *ignore):
+        def peek(barrier, b, *ignore):
             barrier.wait()
-            b.peek(into)
+            b.peek()
 
         def close(barrier, b, *ignore):
             barrier.wait()
@@ -107,6 +107,7 @@ def sizeof(barrier, b, *ignore):
         self.check([truncate] + [readline] * 10, self.ioclass(b'0\n'*20480))
         self.check([truncate] + [readlines] * 10, self.ioclass(b'0\n'*20480))
         self.check([truncate] + [readinto] * 10, self.ioclass(b'0\n'*204800), bytearray(b'0\n'*204800))
+        self.check([truncate] + [peek] * 10, self.ioclass(b'0\n'*204800))
         self.check([close] + [write] * 10, self.ioclass())
         self.check([truncate] + [getvalue] * 10, self.ioclass(b'0\n'*204800))
         self.check([truncate] + [getbuffer] * 10, self.ioclass(b'0\n'*204800))