From 9a1897c884ff4070646ed231aab424dfc6d4c8bb Mon Sep 17 00:00:00 2001
From: Antti Kaihola <antti.kaihola@eniram.fi>
Date: Fri, 10 Sep 2021 13:50:29 +0300
Subject: [PATCH 1/3] Fix patching of `io.TextWrapper` in tests

`patch("io.TextIOWrapper")` wouldn't actually cause
`io.TextIOWrapper()` to return the `StringIO` object created by the
test. This started to fail as soon as `content=` is non-empty.
---
 tests/test_black.py | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/tests/test_black.py b/tests/test_black.py
index 398a528bee9..9d590c1c03d 100644
--- a/tests/test_black.py
+++ b/tests/test_black.py
@@ -25,7 +25,7 @@
 )
 import pytest
 import unittest
-from unittest.mock import patch, MagicMock
+from unittest.mock import patch, MagicMock, Mock
 from parameterized import parameterized
 
 import click
@@ -1689,7 +1689,9 @@ def test_reformat_one_with_stdin_and_existing_path(self) -> None:
 
     def test_reformat_one_with_stdin_empty(self) -> None:
         output = io.StringIO()
-        with patch("io.TextIOWrapper", lambda *args, **kwargs: output):
+        mock_io = Mock()
+        mock_io.TextIOWrapper.return_value = output
+        with patch.object(black, "io", mock_io):
             try:
                 black.format_stdin_to_stdout(
                     fast=True,

From c068ec3ab8ca19c7cc8805b487b0723f63d2e052 Mon Sep 17 00:00:00 2001
From: Antti Kaihola <antti.kaihola@eniram.fi>
Date: Fri, 10 Sep 2021 13:52:40 +0300
Subject: [PATCH 2/3] Update change log

---
 CHANGES.md | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/CHANGES.md b/CHANGES.md
index 4b5a291c7b9..bfb12b9676c 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -7,6 +7,10 @@
 - Fix missing modules in self-contained binaries (#2466)
 - Fix missing toml extra used during installation (#2475)
 
+### Tests
+
+- Fix patching of `io.TextWrapper` (#2489)
+
 ## 21.8b0
 
 ### _Black_

From a99ad3ab05059ffaad153ecd778324c5f5697ada Mon Sep 17 00:00:00 2001
From: Antti Kaihola <13725+akaihola@users.noreply.github.com>
Date: Sat, 11 Sep 2021 18:55:02 +0300
Subject: [PATCH 3/3] Update CHANGES.md

Co-authored-by: Jelle Zijlstra <jelle.zijlstra@gmail.com>
---
 CHANGES.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/CHANGES.md b/CHANGES.md
index bfb12b9676c..2961dbb320b 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -9,7 +9,7 @@
 
 ### Tests
 
-- Fix patching of `io.TextWrapper` (#2489)
+- Fix patching of `io.TextIOWrapper` (#2489)
 
 ## 21.8b0