Second run of tox -e py results in a test error for test marked with no_python2 ...

[etc/vim.git] / tests / test_black.py

diff --git a/tests/test_black.py b/tests/test_black.py
index 5262c0ee44c4e09d2e6f44130179c59a5aa9247b..42ac119324c0c41abfc3545da83a7ff933832dfc 100644 (file)
--- a/tests/test_black.py
+++ b/tests/test_black.py
@@ -6,6 +6,7 @@ from concurrent.futures import ThreadPoolExecutor
 from contextlib import contextmanager
 from dataclasses import replace
 import inspect
+import io
 from io import BytesIO
 import os
 from pathlib import Path
@@ -1682,6 +1683,20 @@ class BlackTestCase(BlackBaseTestCase):
             # __BLACK_STDIN_FILENAME__ should have been stripped
             report.done.assert_called_with(expected, black.Changed.YES)
 
+    def test_reformat_one_with_stdin_empty(self) -> None:
+        output = io.StringIO()
+        with patch("io.TextIOWrapper", lambda *args, **kwargs: output):
+            try:
+                black.format_stdin_to_stdout(
+                    fast=True,
+                    content="",
+                    write_back=black.WriteBack.YES,
+                    mode=DEFAULT_MODE,
+                )
+            except io.UnsupportedOperation:
+                pass  # StringIO does not support detach
+            assert output.getvalue() == ""
+
     def test_gitignore_exclude(self) -> None:
         path = THIS_DIR / "data" / "include_exclude_tests"
         include = re.compile(r"\.pyi?$")