From 7a093f0303c3fa7fee0b6742b7c6a3ff03438ace Mon Sep 17 00:00:00 2001
From: Marco Edward Gorelli <marcogorelli@protonmail.com>
Date: Sat, 28 Aug 2021 16:27:55 +0100
Subject: [PATCH 1/1] add test which covers stdin filename ipynb (#2454)

---
 tests/test_black.py | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/tests/test_black.py b/tests/test_black.py
index 8a37f7c..398a528 100644
--- a/tests/test_black.py
+++ b/tests/test_black.py
@@ -1639,6 +1639,30 @@ 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_filename_ipynb(self) -> None:
+        with patch(
+            "black.format_stdin_to_stdout",
+            return_value=lambda *args, **kwargs: black.Changed.YES,
+        ) as fsts:
+            report = MagicMock()
+            p = "foo.ipynb"
+            path = Path(f"__BLACK_STDIN_FILENAME__{p}")
+            expected = Path(p)
+            black.reformat_one(
+                path,
+                fast=True,
+                write_back=black.WriteBack.YES,
+                mode=DEFAULT_MODE,
+                report=report,
+            )
+            fsts.assert_called_once_with(
+                fast=True,
+                write_back=black.WriteBack.YES,
+                mode=replace(DEFAULT_MODE, is_ipynb=True),
+            )
+            # __BLACK_STDIN_FILENAME__ should have been stripped
+            report.done.assert_called_with(expected, black.Changed.YES)
+
     def test_reformat_one_with_stdin_and_existing_path(self) -> None:
         with patch(
             "black.format_stdin_to_stdout",
-- 
2.39.5