Workaround pytest issue 5997

It seems that the bug described in pytest-dev/pytest#5997
is preventing stderr to be captured by capsys.

The workaround consists in using both `capfd` and `--capture=tee-sys`
(or just `-s`).

Author: abravalheri

tests/test_django.py

@@ -111,7 +111,7 @@ def test_cli_without_django(tmpfolder):
         assert not Path(path).exists()
 
 
-def test_cli_with_django_and_update(tmpfolder, capsys):
+def test_cli_with_django_and_update(tmpfolder, capfd):
     # Given a project exists
     create_project(project_path=PROJ_NAME, config_files=NO_CONFIG)
     # NO_CONFIG: avoid extra config from dev's machine interference
@@ -122,7 +122,7 @@ def test_cli_with_django_and_update(tmpfolder, capsys):
     # --no-config: avoid extra config from dev's machine interference
 
     # then a warning should be displayed
-    out, err = capsys.readouterr()
+    out, err = capfd.readouterr()
     assert all(
         warn in out + err
         for warn in ("external tools", "not supported", "will be ignored")

tox.ini

@@ -25,7 +25,9 @@ extras =
     all
     testing
 commands =
-    pytest {posargs}
+    pytest  --capture=tee-sys {posargs}
+# --capture=tee-sys is need otherwise the test fails, I believe this is related to:
+# https://github.com/pytest-dev/pytest/issues/5997
 
 
 [testenv:{clean,build}]