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.venv/Lib/site-packages/notebook/services/contents/tests/test_fileio.py

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+"""Tests for file IO"""
+
+# Copyright (c) Jupyter Development Team.
+# Distributed under the terms of the Modified BSD License.
+
+import os.path
+import unittest
+import pytest
+import stat
+import sys
+
+from ..fileio import atomic_writing
+
+from ipython_genutils.tempdir import TemporaryDirectory
+
+umask = 0
+
+def test_atomic_writing():
+    class CustomExc(Exception):
+        pass
+
+    with TemporaryDirectory() as td:
+        f1 = os.path.join(td, 'penguin')
+        with open(f1, 'w') as f:
+            f.write('Before')
+
+        if os.name != 'nt':
+            os.chmod(f1, 0o701)
+            orig_mode = stat.S_IMODE(os.stat(f1).st_mode)
+
+        f2 = os.path.join(td, 'flamingo')
+        try:
+            os.symlink(f1, f2)
+            have_symlink = True
+        except (AttributeError, NotImplementedError, OSError):
+            # AttributeError: Python doesn't support it
+            # NotImplementedError: The system doesn't support it
+            # OSError: The user lacks the privilege (Windows)
+            have_symlink = False
+
+        with pytest.raises(CustomExc):
+            with atomic_writing(f1) as f:
+                f.write('Failing write')
+                raise CustomExc
+
+        # Because of the exception, the file should not have been modified
+        with open(f1) as f:
+            assert f.read() == 'Before'
+
+        with atomic_writing(f1) as f:
+            f.write('Overwritten')
+
+        with open(f1) as f:
+            assert f.read() == 'Overwritten'
+
+        if os.name != 'nt':
+            mode = stat.S_IMODE(os.stat(f1).st_mode)
+            assert mode == orig_mode
+
+        if have_symlink:
+            # Check that writing over a file preserves a symlink
+            with atomic_writing(f2) as f:
+                f.write('written from symlink')
+
+            with open(f1) as f:
+                assert f.read() == 'written from symlink'
+
+class TestWithSetUmask(unittest.TestCase):
+    def setUp(self):
+        # save umask
+        global umask
+        umask = os.umask(0)
+        os.umask(umask)
+
+    def tearDown(self):
+        # restore umask
+        os.umask(umask)
+
+    @pytest.mark.skipif(sys.platform == "win32", reason="do not run on windows")
+    def test_atomic_writing_umask(self):
+        with TemporaryDirectory() as td:
+            os.umask(0o022)
+            f1 = os.path.join(td, '1')
+            with atomic_writing(f1) as f:
+                f.write('1')
+            mode = stat.S_IMODE(os.stat(f1).st_mode)
+            assert mode == 0o644
+
+            os.umask(0o057)
+            f2 = os.path.join(td, '2')
+            with atomic_writing(f2) as f:
+                f.write('2')
+            mode = stat.S_IMODE(os.stat(f2).st_mode)
+            assert mode == 0o620
+
+
+def test_atomic_writing_newlines():
+    with TemporaryDirectory() as td:
+        path = os.path.join(td, 'testfile')
+
+        lf = 'a\nb\nc\n'
+        plat = lf.replace('\n', os.linesep)
+        crlf = lf.replace('\n', '\r\n')
+
+        # test default
+        with open(path, 'w') as f:
+            f.write(lf)
+        with open(path, newline='') as f:
+            read = f.read()
+        assert read == plat
+
+        # test newline=LF
+        with open(path, 'w', newline='\n') as f:
+            f.write(lf)
+        with open(path, newline='') as f:
+            read = f.read()
+        assert read == lf
+
+        # test newline=CRLF
+        with atomic_writing(path, newline='\r\n') as f:
+            f.write(lf)
+        with open(path, newline='') as f:
+            read = f.read()
+        assert read == crlf
+
+        # test newline=no convert
+        text = 'crlf\r\ncr\rlf\n'
+        with atomic_writing(path, newline='') as f:
+            f.write(text)
+        with open(path, newline='') as f:
+            read = f.read()
+        assert read == text