Fix: Inconsistent newlines on Windows (#402)

* Update test_toml_file.py

* Update toml_file.py

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

Author: DimmaDont

tests/test_toml_file.py

@@ -105,3 +105,13 @@ def test_default_eol_is_os_linesep(tmpdir):
     linesep = os.linesep.encode()
     with open(toml_path, "rb") as f:
         assert f.read() == b"a = 1" + linesep + b"b = 2" + linesep
+
+
+def test_readwrite_eol_windows(tmpdir):
+    toml_path = str(tmpdir / "pyproject.toml")
+    doc = TOMLDocument()
+    doc.add("a", 1)
+    f = TOMLFile(toml_path)
+    f.write(doc)
+    readback = f.read()
+    assert doc.as_string() == readback.as_string()

tomlkit/toml_file.py

@@ -37,6 +37,7 @@ def read(self) -> TOMLDocument:
                 num_win_eol = content.count("\r\n")
                 if num_win_eol == num_newline:
                     self._linesep = "\r\n"
+                    content = content.replace("\r\n", "\n")
                 elif num_win_eol == 0:
                     self._linesep = "\n"
                 else: