Pin black in CI

This temporarily fixes an incompatibility between black and darker

.github/workflows/python-package.yml

@@ -1,40 +1,40 b''
 # This workflow will install Python dependencies, run tests and lint with a variety of Python versions
 # For more information see: https://help.github.com/actions/language-and-framework-guides/using-python-with-github-actions
 
 name: Python package
 
 on:
   push:
     branches: [ master, 7.x ]
   pull_request:
     branches: [ master, 7.x ]
 
 jobs:
   formatting:
 
     runs-on: ubuntu-latest
     timeout-minutes: 5
     strategy:
       matrix:
         python-version: [3.8]
 
     steps:
     - uses: actions/checkout@v2
       with: 
         fetch-depth: 0
     - name: Set up Python ${{ matrix.python-version }}
       uses: actions/setup-python@v2
       with:
         python-version: ${{ matrix.python-version }}
     - name: Install dependencies
       run: |
         python -m pip install --upgrade pip
-        pip install darker
+        pip install darker black==21.12b0
     - name: Lint with darker
       run: |
         darker -r 60625f241f298b5039cb2debc365db38aa7bb522 --check --diff . || (
         echo "Changes need auto-formatting. Run:"
         echo "    darker -r 60625f241f298b5039cb2debc365db38aa7bb522"
         echo "then commit and push changes to fix."
         exit 1
         )

IPython/tests/cve.py

@@ -1,56 +1,65 b''
 """
 Test that CVEs stay fixed. 
 """
 
 from IPython.utils.tempdir import TemporaryDirectory, TemporaryWorkingDirectory
 from pathlib import Path
 import random
 import sys
 import os
 import string
 import subprocess
 import time
 
+
 def test_cve_2022_21699():
     """
     Here we test CVE-2022-21699.
 
     We create a temporary directory, cd into it. 
     Make a profile file that should not be executed and start IPython in a subprocess, 
     checking for the value.
 
 
 
     """
 
-    dangerous_profile_dir = Path('profile_default')
+    dangerous_profile_dir = Path("profile_default")
 
-    dangerous_startup_dir = dangerous_profile_dir / 'startup'
-    dangerous_expected = 'CVE-2022-21699-'+''.join([random.choice(string.ascii_letters) for i in range(10)])
+    dangerous_startup_dir = dangerous_profile_dir / "startup"
+    dangerous_expected = "CVE-2022-21699-" + "".join(
+        [random.choice(string.ascii_letters) for i in range(10)]
+    )
 
     with TemporaryWorkingDirectory() as t:
         dangerous_startup_dir.mkdir(parents=True)
-        (dangerous_startup_dir/ 'foo.py').write_text(f'print("{dangerous_expected}")')
+        (dangerous_startup_dir / "foo.py").write_text(f'print("{dangerous_expected}")')
         # 1 sec to make sure FS is flushed.
         #time.sleep(1)
-        cmd = [sys.executable,'-m', 'IPython']
+        cmd = [sys.executable, "-m", "IPython"]
         env = os.environ.copy()
-        env['IPY_TEST_SIMPLE_PROMPT'] = '1'
-
+        env["IPY_TEST_SIMPLE_PROMPT"] = "1"
 
         # First we fake old behavior, making sure the profile is/was actually dangerous
-        p_dangerous = subprocess.Popen(cmd + [f'--profile-dir={dangerous_profile_dir}'], env=env, stdin=subprocess.PIPE,
-                stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+        p_dangerous = subprocess.Popen(
+            cmd + [f"--profile-dir={dangerous_profile_dir}"],
+            env=env,
+            stdin=subprocess.PIPE,
+            stdout=subprocess.PIPE,
+            stderr=subprocess.PIPE,
+        )
         out_dangerous, err_dangerouns = p_dangerous.communicate(b"exit\r")
         assert dangerous_expected in out_dangerous.decode()
 
         # Now that we know it _would_ have been dangerous, we test it's not loaded
-        p = subprocess.Popen(cmd, env=env, stdin=subprocess.PIPE,
-                stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+        p = subprocess.Popen(
+            cmd,
+            env=env,
+            stdin=subprocess.PIPE,
+            stdout=subprocess.PIPE,
+            stderr=subprocess.PIPE,
+        )
         out, err = p.communicate(b"exit\r")
-        assert b'IPython' in out
+        assert b"IPython" in out
         assert dangerous_expected not in out.decode()
-        assert err == b''
-
-
-
+        assert err == b""