From 9c9ed3cc7799922db11ed96296ba218ac0188cda Mon Sep 17 00:00:00 2001
From: mshafer-NI <23644905+mshafer-NI@users.noreply.github.com>
Date: Wed, 12 Nov 2025 16:41:24 -0600
Subject: [PATCH 01/10] setup a failing test

---
 poetry.lock       | 21 ++++++++++++++++++--
 pyproject.toml    |  2 +-
 tests/conftest.py | 49 +++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 69 insertions(+), 3 deletions(-)

diff --git a/poetry.lock b/poetry.lock
index f7bd279f..626cfb73 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -1,4 +1,4 @@
-# This file is automatically @generated by Poetry 1.8.2 and should not be changed by hand.
+# This file is automatically @generated by Poetry 1.8.3 and should not be changed by hand.
 
 [[package]]
 name = "better-diff"
@@ -419,6 +419,23 @@ files = [
 click = ">=6.0"
 pytest = ">=5.0"
 
+[[package]]
+name = "pytest-mock"
+version = "3.14.1"
+description = "Thin-wrapper around the mock package for easier use with pytest"
+optional = false
+python-versions = ">=3.8"
+files = [
+    {file = "pytest_mock-3.14.1-py3-none-any.whl", hash = "sha256:178aefcd11307d874b4cd3100344e7e2d888d9791a6a1d9bfe90fbc1b74fd1d0"},
+    {file = "pytest_mock-3.14.1.tar.gz", hash = "sha256:159e9edac4c451ce77a5cdb9fc5d1100708d2dd4ba3c3df572f14097351af80e"},
+]
+
+[package.dependencies]
+pytest = ">=6.2.5"
+
+[package.extras]
+dev = ["pre-commit", "pytest-asyncio", "tox"]
+
 [[package]]
 name = "pytest-snapshot"
 version = "0.9.0"
@@ -495,4 +512,4 @@ files = [
 [metadata]
 lock-version = "2.0"
 python-versions = "^3.8"
-content-hash = "a8aef2d773dabdd18223fcb2aabce153b8a4f45750fe636d15acf5b47143ea16"
+content-hash = "480d0af21c1df570785160169d0a7e89ed92a72f7b5cc4f35251540200a5eeaa"
diff --git a/pyproject.toml b/pyproject.toml
index 03dd7bcb..b7ecd5af 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -56,7 +56,7 @@ pep8-naming = ">=0.11.1"
 pytest = ">=6.0.1"
 pytest_click = ">=1.0.2"
 pytest-snapshot = ">=0.6.3"
-
+pytest-mock = ">=3.8.1"
 
 [tool.poetry.scripts]
 ni-python-styleguide = 'ni_python_styleguide._cli:main'
diff --git a/tests/conftest.py b/tests/conftest.py
index c8fe912f..0130491b 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -1,6 +1,10 @@
 """Useful plugins/fixtures which can (and should) be used in any test."""
 
+import builtins
+import functools
+import io
 import os
+import pathlib
 
 import click.testing
 import pytest
@@ -59,3 +63,48 @@ def chdir():
     cwd = os.getcwd()
     yield os.chdir
     os.chdir(cwd)
+
+@pytest.fixture(autouse=True)
+def fake_open(mocker):
+    """Mock open to prevent actual file system writes during tests."""
+    original_open = builtins.open
+    # original_path_write = pathlib.Path.write_text
+
+    def open_with_default_ascii(func):
+        @functools.wraps(func)
+        def wrapper(*args, **kwargs):
+            if len(args) > 1:
+                mode = args[1]
+            else:
+                mode = kwargs.get('mode', 'r')
+            if 'b' not in mode and 'encoding' not in kwargs:
+                kwargs['encoding'] = 'ascii'
+            return func(*args, **kwargs)
+
+        return wrapper
+
+    original_io_open = io.open
+
+    def io_open_with_default_encoding(func):
+        @functools.wraps(func)
+        def wrapper(*args, **kwargs):
+            # check for encoding in args
+            # self, mode, buffering, encoding, errors, newline
+            mode = kwargs.get('mode', 'r')
+            if len(args) > 1:
+                mode = args[1]
+
+            if len(args) > 3:
+                encoding = args[3]
+                args = list(args[:3])
+                for name, value in zip(['errors', 'newline'], args[4:]):
+                    kwargs[name] = value
+            if 'encoding' not in kwargs and 'b' not in mode:
+                kwargs['encoding'] = 'ascii'
+            return func(*args, **kwargs)
+
+        return wrapper
+
+    _mock_open = mocker.patch("builtins.open", side_effect=open_with_default_ascii(original_open))
+    _mock_path_write = mocker.patch("io.open", side_effect=io_open_with_default_encoding(original_io_open))
+    yield None

From 2ff4b631a32eef004aa065f14f119810fd0605b7 Mon Sep 17 00:00:00 2001
From: mshafer-NI <23644905+mshafer-NI@users.noreply.github.com>
Date: Wed, 12 Nov 2025 16:41:29 -0600
Subject: [PATCH 02/10] get fixture to actually work with help from copilot

---
 tests/conftest.py | 79 ++++++++++++++++++++++-------------------------
 1 file changed, 37 insertions(+), 42 deletions(-)

diff --git a/tests/conftest.py b/tests/conftest.py
index 0130491b..cee7f9e4 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -11,7 +11,6 @@
 
 from ni_python_styleguide.__main__ import main as styleguide_main
 
-
 def pytest_collection_modifyitems(items):
     """Ignores deprecation warnings in all tests."""
     for item in items:
@@ -64,47 +63,43 @@ def chdir():
     yield os.chdir
     os.chdir(cwd)
 
+
 @pytest.fixture(autouse=True)
-def fake_open(mocker):
-    """Mock open to prevent actual file system writes during tests."""
+def force_ascii_encoding(monkeypatch):
+    """Force ASCII encoding as default for all file operations to catch missing encoding args."""
+    import locale
+    
+    # Patch locale.getpreferredencoding to return 'ascii'
+    # This affects Path.read_text() and Path.write_text() default encoding
+    monkeypatch.setattr(locale, 'getpreferredencoding', lambda do_setlocale=True: 'ascii')
+    
+    # Patch builtins.open to use ASCII when encoding not specified
     original_open = builtins.open
-    # original_path_write = pathlib.Path.write_text
-
-    def open_with_default_ascii(func):
-        @functools.wraps(func)
-        def wrapper(*args, **kwargs):
-            if len(args) > 1:
-                mode = args[1]
-            else:
-                mode = kwargs.get('mode', 'r')
-            if 'b' not in mode and 'encoding' not in kwargs:
-                kwargs['encoding'] = 'ascii'
-            return func(*args, **kwargs)
-
-        return wrapper
-
-    original_io_open = io.open
-
-    def io_open_with_default_encoding(func):
-        @functools.wraps(func)
-        def wrapper(*args, **kwargs):
-            # check for encoding in args
-            # self, mode, buffering, encoding, errors, newline
-            mode = kwargs.get('mode', 'r')
-            if len(args) > 1:
-                mode = args[1]
-
-            if len(args) > 3:
-                encoding = args[3]
-                args = list(args[:3])
-                for name, value in zip(['errors', 'newline'], args[4:]):
-                    kwargs[name] = value
-            if 'encoding' not in kwargs and 'b' not in mode:
+    
+    def ascii_open(*args, **kwargs):
+        if 'encoding' not in kwargs:
+            mode = args[1] if len(args) > 1 else kwargs.get('mode', 'r')
+            if 'b' not in mode:
                 kwargs['encoding'] = 'ascii'
-            return func(*args, **kwargs)
-
-        return wrapper
-
-    _mock_open = mocker.patch("builtins.open", side_effect=open_with_default_ascii(original_open))
-    _mock_path_write = mocker.patch("io.open", side_effect=io_open_with_default_encoding(original_io_open))
-    yield None
+        return original_open(*args, **kwargs)
+    
+    monkeypatch.setattr(builtins, 'open', ascii_open)
+    
+    # Patch pathlib.Path.read_text and write_text to use ASCII when encoding not specified
+    original_read_text = pathlib.Path.read_text
+    original_write_text = pathlib.Path.write_text
+    
+    def ascii_read_text(self, encoding=None, errors=None):
+        if encoding is None:
+            encoding = 'ascii'
+        return original_read_text(self, encoding=encoding, errors=errors)
+    
+    def ascii_write_text(self, data, encoding=None, errors=None, newline=None):
+        if encoding is None:
+            encoding = 'ascii'
+        return original_write_text(self, data, encoding=encoding, errors=errors, newline=newline)
+    
+    monkeypatch.setattr(pathlib.Path, 'read_text', ascii_read_text)
+    monkeypatch.setattr(pathlib.Path, 'write_text', ascii_write_text)
+
+    yield None
\ No newline at end of file

From 37f0df4c66b810919c6723a58a3d66e3296b6f40 Mon Sep 17 00:00:00 2001
From: mshafer-NI <23644905+mshafer-NI@users.noreply.github.com>
Date: Wed, 12 Nov 2025 16:41:32 -0600
Subject: [PATCH 03/10] make failing tests

---
 .../unicode_in_files/input.py                 | 10 ++++++
 .../unicode_in_files/output.py.txt            | 10 ++++++
 .../unicode_in_files/output__aggressive.py    | 12 +++++++
 .../unicode_example/input.py                  | 29 +++++++++++++++++
 .../unicode_example/output.py.txt             | 31 +++++++++++++++++++
 .../file_with_unicode/input.py                | 29 +++++++++++++++++
 .../file_with_unicode/output.py               | 31 +++++++++++++++++++
 tests/test_cli/test_format.py                 |  2 +-
 8 files changed, 153 insertions(+), 1 deletion(-)
 create mode 100644 tests/test_cli/fix_test_cases__snapshots/unicode_example/input.py
 create mode 100644 tests/test_cli/fix_test_cases__snapshots/unicode_example/output.py.txt
 create mode 100644 tests/test_cli/format_test_cases__snapshots/file_with_unicode/input.py
 create mode 100644 tests/test_cli/format_test_cases__snapshots/file_with_unicode/output.py

diff --git a/tests/test_cli/acknowledge_existing_errors_test_cases__snapshots/unicode_in_files/input.py b/tests/test_cli/acknowledge_existing_errors_test_cases__snapshots/unicode_in_files/input.py
index b8cb656d..157b0d82 100644
--- a/tests/test_cli/acknowledge_existing_errors_test_cases__snapshots/unicode_in_files/input.py
+++ b/tests/test_cli/acknowledge_existing_errors_test_cases__snapshots/unicode_in_files/input.py
@@ -17,3 +17,13 @@ def problem_chars(self):
 def method_withBadName_andParams(my_normal_param, myBadlyNamedParam, my_other_Bad_param):
     """Provide example where black will want to split out result."""
     return 5 + 7
+
+data =   ("device_name, supported_encodings",
+    [
+        ("Gerät", ["1252", "iso-8859-1", "utf-8"]),
+        ("l' appareil", ["1252", "iso-8859-1", "utf-8"]),
+        ("デバイス", ["932", "shift-jis", "utf-8"]),
+        ("장치", ["utf-8", "euc-kr"]),
+        ("设备", ["utf-8", "gbk"]),
+    ],
+)
\ No newline at end of file
diff --git a/tests/test_cli/acknowledge_existing_errors_test_cases__snapshots/unicode_in_files/output.py.txt b/tests/test_cli/acknowledge_existing_errors_test_cases__snapshots/unicode_in_files/output.py.txt
index 5aa604a2..230514f5 100644
--- a/tests/test_cli/acknowledge_existing_errors_test_cases__snapshots/unicode_in_files/output.py.txt
+++ b/tests/test_cli/acknowledge_existing_errors_test_cases__snapshots/unicode_in_files/output.py.txt
@@ -17,3 +17,13 @@ class Foo:
 def method_withBadName_andParams(my_normal_param, myBadlyNamedParam, my_other_Bad_param):  # noqa: N803, N802 - argument name 'myBadlyNamedParam' should be lowercase (auto-generated noqa), function name 'method_withBadName_andParams' should be lowercase (auto-generated noqa)
     """Provide example where black will want to split out result."""
     return 5 + 7
+
+data =   ("device_name, supported_encodings",
+    [
+        ("Gerät", ["1252", "iso-8859-1", "utf-8"]),
+        ("l' appareil", ["1252", "iso-8859-1", "utf-8"]),
+        ("デバイス", ["932", "shift-jis", "utf-8"]),
+        ("장치", ["utf-8", "euc-kr"]),
+        ("设备", ["utf-8", "gbk"]),
+    ],
+)
\ No newline at end of file
diff --git a/tests/test_cli/acknowledge_existing_errors_test_cases__snapshots/unicode_in_files/output__aggressive.py b/tests/test_cli/acknowledge_existing_errors_test_cases__snapshots/unicode_in_files/output__aggressive.py
index 68a68cf4..550b7d72 100644
--- a/tests/test_cli/acknowledge_existing_errors_test_cases__snapshots/unicode_in_files/output__aggressive.py
+++ b/tests/test_cli/acknowledge_existing_errors_test_cases__snapshots/unicode_in_files/output__aggressive.py
@@ -21,3 +21,15 @@ def method_withBadName_andParams(  # noqa: N802 - function name 'method_withBadN
 ):
     """Provide example where black will want to split out result."""
     return 5 + 7
+
+
+data = (
+    "device_name, supported_encodings",
+    [
+        ("Gerät", ["1252", "iso-8859-1", "utf-8"]),
+        ("l' appareil", ["1252", "iso-8859-1", "utf-8"]),
+        ("デバイス", ["932", "shift-jis", "utf-8"]),
+        ("장치", ["utf-8", "euc-kr"]),
+        ("设备", ["utf-8", "gbk"]),
+    ],
+)
diff --git a/tests/test_cli/fix_test_cases__snapshots/unicode_example/input.py b/tests/test_cli/fix_test_cases__snapshots/unicode_example/input.py
new file mode 100644
index 00000000..157b0d82
--- /dev/null
+++ b/tests/test_cli/fix_test_cases__snapshots/unicode_example/input.py
@@ -0,0 +1,29 @@
+"""Unicode in file should not cause error (e.g., ©)."""
+
+
+class Foo:
+    """Example class with unicode consts."""
+
+    def __init__(self) -> None:
+        """Instantiate Foo class."""
+        self._problem_chars = "π”"
+
+    @property
+    def problem_chars(self):
+        """Return stored string with a unicode char."""
+        return self._problem_chars
+
+
+def method_withBadName_andParams(my_normal_param, myBadlyNamedParam, my_other_Bad_param):
+    """Provide example where black will want to split out result."""
+    return 5 + 7
+
+data =   ("device_name, supported_encodings",
+    [
+        ("Gerät", ["1252", "iso-8859-1", "utf-8"]),
+        ("l' appareil", ["1252", "iso-8859-1", "utf-8"]),
+        ("デバイス", ["932", "shift-jis", "utf-8"]),
+        ("장치", ["utf-8", "euc-kr"]),
+        ("设备", ["utf-8", "gbk"]),
+    ],
+)
\ No newline at end of file
diff --git a/tests/test_cli/fix_test_cases__snapshots/unicode_example/output.py.txt b/tests/test_cli/fix_test_cases__snapshots/unicode_example/output.py.txt
new file mode 100644
index 00000000..ea2d139d
--- /dev/null
+++ b/tests/test_cli/fix_test_cases__snapshots/unicode_example/output.py.txt
@@ -0,0 +1,31 @@
+"""Unicode in file should not cause error (e.g., ©)."""
+
+
+class Foo:
+    """Example class with unicode consts."""
+
+    def __init__(self) -> None:
+        """Instantiate Foo class."""
+        self._problem_chars = "π”"
+
+    @property
+    def problem_chars(self):
+        """Return stored string with a unicode char."""
+        return self._problem_chars
+
+
+def method_withBadName_andParams(my_normal_param, myBadlyNamedParam, my_other_Bad_param):
+    """Provide example where black will want to split out result."""
+    return 5 + 7
+
+
+data = (
+    "device_name, supported_encodings",
+    [
+        ("Gerät", ["1252", "iso-8859-1", "utf-8"]),
+        ("l' appareil", ["1252", "iso-8859-1", "utf-8"]),
+        ("デバイス", ["932", "shift-jis", "utf-8"]),
+        ("장치", ["utf-8", "euc-kr"]),
+        ("设备", ["utf-8", "gbk"]),
+    ],
+)
diff --git a/tests/test_cli/format_test_cases__snapshots/file_with_unicode/input.py b/tests/test_cli/format_test_cases__snapshots/file_with_unicode/input.py
new file mode 100644
index 00000000..157b0d82
--- /dev/null
+++ b/tests/test_cli/format_test_cases__snapshots/file_with_unicode/input.py
@@ -0,0 +1,29 @@
+"""Unicode in file should not cause error (e.g., ©)."""
+
+
+class Foo:
+    """Example class with unicode consts."""
+
+    def __init__(self) -> None:
+        """Instantiate Foo class."""
+        self._problem_chars = "π”"
+
+    @property
+    def problem_chars(self):
+        """Return stored string with a unicode char."""
+        return self._problem_chars
+
+
+def method_withBadName_andParams(my_normal_param, myBadlyNamedParam, my_other_Bad_param):
+    """Provide example where black will want to split out result."""
+    return 5 + 7
+
+data =   ("device_name, supported_encodings",
+    [
+        ("Gerät", ["1252", "iso-8859-1", "utf-8"]),
+        ("l' appareil", ["1252", "iso-8859-1", "utf-8"]),
+        ("デバイス", ["932", "shift-jis", "utf-8"]),
+        ("장치", ["utf-8", "euc-kr"]),
+        ("设备", ["utf-8", "gbk"]),
+    ],
+)
\ No newline at end of file
diff --git a/tests/test_cli/format_test_cases__snapshots/file_with_unicode/output.py b/tests/test_cli/format_test_cases__snapshots/file_with_unicode/output.py
new file mode 100644
index 00000000..ea2d139d
--- /dev/null
+++ b/tests/test_cli/format_test_cases__snapshots/file_with_unicode/output.py
@@ -0,0 +1,31 @@
+"""Unicode in file should not cause error (e.g., ©)."""
+
+
+class Foo:
+    """Example class with unicode consts."""
+
+    def __init__(self) -> None:
+        """Instantiate Foo class."""
+        self._problem_chars = "π”"
+
+    @property
+    def problem_chars(self):
+        """Return stored string with a unicode char."""
+        return self._problem_chars
+
+
+def method_withBadName_andParams(my_normal_param, myBadlyNamedParam, my_other_Bad_param):
+    """Provide example where black will want to split out result."""
+    return 5 + 7
+
+
+data = (
+    "device_name, supported_encodings",
+    [
+        ("Gerät", ["1252", "iso-8859-1", "utf-8"]),
+        ("l' appareil", ["1252", "iso-8859-1", "utf-8"]),
+        ("デバイス", ["932", "shift-jis", "utf-8"]),
+        ("장치", ["utf-8", "euc-kr"]),
+        ("设备", ["utf-8", "gbk"]),
+    ],
+)
diff --git a/tests/test_cli/test_format.py b/tests/test_cli/test_format.py
index dad47b67..d56509f6 100644
--- a/tests/test_cli/test_format.py
+++ b/tests/test_cli/test_format.py
@@ -24,7 +24,7 @@ def test_given_input_file__produces_expected_output_simple(
     output = styleguide_command(command="format")
 
     assert output.exit_code in (True, 0), f"Error in running:\n{output}"
-    result = test_file.read_text()
+    result = test_file.read_text(encoding="utf-8")
     snapshot.snapshot_dir = test_dir
     snapshot.assert_match(result, "output.py")
 

From 96be8e043337dabaaf39de34792e1adf191365c6 Mon Sep 17 00:00:00 2001
From: mshafer-NI <23644905+mshafer-NI@users.noreply.github.com>
Date: Wed, 12 Nov 2025 16:41:37 -0600
Subject: [PATCH 04/10] make it pass

---
 ni_python_styleguide/_fix.py                  | 10 +++---
 ni_python_styleguide/_utils/code_analysis.py  |  2 +-
 .../unicode_example/output__aggressive.py     | 35 +++++++++++++++++++
 .../file_with_unicode/output.diff             | 14 ++++++++
 4 files changed, 55 insertions(+), 6 deletions(-)
 create mode 100644 tests/test_cli/fix_test_cases__snapshots/unicode_example/output__aggressive.py
 create mode 100644 tests/test_cli/format_test_cases__snapshots/file_with_unicode/output.diff

diff --git a/ni_python_styleguide/_fix.py b/ni_python_styleguide/_fix.py
index 332ee341..dd0d8db3 100644
--- a/ni_python_styleguide/_fix.py
+++ b/ni_python_styleguide/_fix.py
@@ -21,7 +21,7 @@
 
 
 def _sort_imports(file: pathlib.Path, app_import_names):
-    raw = file.read_text()
+    raw = file.read_text(encoding="utf-8")
     isort_config = isort.Config(
         settings_file=str(_config_constants.ISORT_CONFIG_FILE),
         known_first_party=filter(None, app_import_names.split(",")),
@@ -30,7 +30,7 @@ def _sort_imports(file: pathlib.Path, app_import_names):
         raw,
         config=isort_config,
     )
-    file.write_text(output)
+    file.write_text(output, encoding="utf-8")
 
 
 def _format_imports(file: pathlib.Path, app_import_names: Iterable[str]) -> None:
@@ -117,13 +117,13 @@ def fix(
                     )
             else:
                 with temp_file.multi_access_tempfile(suffix="__" + bad_file.name) as working_file:
-                    working_file.write_text(bad_file.read_text())
+                    working_file.write_text(bad_file.read_text(encoding="utf-8"), encoding="utf-8")
                     _format.format(working_file, "-q")
                     _format_imports(file=working_file, app_import_names=app_import_names)
 
                     diff_lines = better_diff.unified_plus.format_diff(
-                        bad_file.read_text(),
-                        working_file.read_text(),
+                        bad_file.read_text(encoding="utf-8"),
+                        working_file.read_text(encoding="utf-8"),
                         fromfile=f"{_posix_relative_if_under(bad_file, pathlib.Path.cwd())}",
                         tofile=f"{_posix_relative_if_under(bad_file, pathlib.Path.cwd())}_formatted",
                     )
diff --git a/ni_python_styleguide/_utils/code_analysis.py b/ni_python_styleguide/_utils/code_analysis.py
index 7c9faabe..5fcaaaeb 100644
--- a/ni_python_styleguide/_utils/code_analysis.py
+++ b/ni_python_styleguide/_utils/code_analysis.py
@@ -11,7 +11,7 @@ def find_import_region(file: pathlib.Path) -> Tuple[int, int]:
     file: pathlib.Path path to file to evaluate
     Return: Tuple[int, int] the start and ending lines (0 based) of the module level imports
     """
-    file_contents = file.read_text()
+    file_contents = file.read_text(encoding="utf-8")
     tree = ast.parse(file_contents)
     end = start = 0
     for node in tree.body:  # only walk top level items
diff --git a/tests/test_cli/fix_test_cases__snapshots/unicode_example/output__aggressive.py b/tests/test_cli/fix_test_cases__snapshots/unicode_example/output__aggressive.py
new file mode 100644
index 00000000..550b7d72
--- /dev/null
+++ b/tests/test_cli/fix_test_cases__snapshots/unicode_example/output__aggressive.py
@@ -0,0 +1,35 @@
+"""Unicode in file should not cause error (e.g., ©)."""
+
+
+class Foo:
+    """Example class with unicode consts."""
+
+    def __init__(self) -> None:
+        """Instantiate Foo class."""
+        self._problem_chars = "π”"
+
+    @property
+    def problem_chars(self):
+        """Return stored string with a unicode char."""
+        return self._problem_chars
+
+
+def method_withBadName_andParams(  # noqa: N802 - function name 'method_withBadName_andParams' should be lowercase (auto-generated noqa)
+    my_normal_param,
+    myBadlyNamedParam,  # noqa: N803 - argument name 'myBadlyNamedParam' should be lowercase (auto-generated noqa)
+    my_other_Bad_param,  # noqa: N803 - argument name 'my_other_Bad_param' should be lowercase (auto-generated noqa)
+):
+    """Provide example where black will want to split out result."""
+    return 5 + 7
+
+
+data = (
+    "device_name, supported_encodings",
+    [
+        ("Gerät", ["1252", "iso-8859-1", "utf-8"]),
+        ("l' appareil", ["1252", "iso-8859-1", "utf-8"]),
+        ("デバイス", ["932", "shift-jis", "utf-8"]),
+        ("장치", ["utf-8", "euc-kr"]),
+        ("设备", ["utf-8", "gbk"]),
+    ],
+)
diff --git a/tests/test_cli/format_test_cases__snapshots/file_with_unicode/output.diff b/tests/test_cli/format_test_cases__snapshots/file_with_unicode/output.diff
new file mode 100644
index 00000000..218c940a
--- /dev/null
+++ b/tests/test_cli/format_test_cases__snapshots/file_with_unicode/output.diff
@@ -0,0 +1,14 @@
+--- input.py
++++ input.py_formatted
+@@ -18,7 +18,9 @@
+     """Provide example where black will want to split out result."""
+     return 5 + 7
+
+-data =   ("device_name, supported_encodings",
++
++data = (
++    "device_name, supported_encodings",
+     [
+         ("Gerät", ["1252", "iso-8859-1", "utf-8"]),
+         ("l' appareil", ["1252", "iso-8859-1", "utf-8"]),
+\ No newline at end of file (input.py)
\ No newline at end of file

From d22e9c52c56a3b84eedccffe4b2c02a1ed1620c5 Mon Sep 17 00:00:00 2001
From: mshafer-NI <23644905+mshafer-NI@users.noreply.github.com>
Date: Wed, 12 Nov 2025 16:41:43 -0600
Subject: [PATCH 05/10] simplify fixture setup

---
 tests/conftest.py | 23 +----------------------
 1 file changed, 1 insertion(+), 22 deletions(-)

diff --git a/tests/conftest.py b/tests/conftest.py
index cee7f9e4..84d4eb4c 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -1,8 +1,5 @@
 """Useful plugins/fixtures which can (and should) be used in any test."""
 
-import builtins
-import functools
-import io
 import os
 import pathlib
 
@@ -67,24 +64,6 @@ def chdir():
 @pytest.fixture(autouse=True)
 def force_ascii_encoding(monkeypatch):
     """Force ASCII encoding as default for all file operations to catch missing encoding args."""
-    import locale
-    
-    # Patch locale.getpreferredencoding to return 'ascii'
-    # This affects Path.read_text() and Path.write_text() default encoding
-    monkeypatch.setattr(locale, 'getpreferredencoding', lambda do_setlocale=True: 'ascii')
-    
-    # Patch builtins.open to use ASCII when encoding not specified
-    original_open = builtins.open
-    
-    def ascii_open(*args, **kwargs):
-        if 'encoding' not in kwargs:
-            mode = args[1] if len(args) > 1 else kwargs.get('mode', 'r')
-            if 'b' not in mode:
-                kwargs['encoding'] = 'ascii'
-        return original_open(*args, **kwargs)
-    
-    monkeypatch.setattr(builtins, 'open', ascii_open)
-    
     # Patch pathlib.Path.read_text and write_text to use ASCII when encoding not specified
     original_read_text = pathlib.Path.read_text
     original_write_text = pathlib.Path.write_text
@@ -102,4 +81,4 @@ def ascii_write_text(self, data, encoding=None, errors=None, newline=None):
     monkeypatch.setattr(pathlib.Path, 'read_text', ascii_read_text)
     monkeypatch.setattr(pathlib.Path, 'write_text', ascii_write_text)
 
-    yield None
\ No newline at end of file
+    yield None

From 2b3349a9ed535f6bf6ad0ccc4a8a240e2aa0612e Mon Sep 17 00:00:00 2001
From: mshafer-NI <23644905+mshafer-NI@users.noreply.github.com>
Date: Wed, 12 Nov 2025 16:41:46 -0600
Subject: [PATCH 06/10] format doesn't fix method names, so make output be able
 to pass

---
 .../format_test_cases__snapshots/file_with_unicode/input.py   | 4 ++--
 .../file_with_unicode/output.diff                             | 2 +-
 .../format_test_cases__snapshots/file_with_unicode/output.py  | 4 ++--
 3 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/tests/test_cli/format_test_cases__snapshots/file_with_unicode/input.py b/tests/test_cli/format_test_cases__snapshots/file_with_unicode/input.py
index 157b0d82..ba2c5364 100644
--- a/tests/test_cli/format_test_cases__snapshots/file_with_unicode/input.py
+++ b/tests/test_cli/format_test_cases__snapshots/file_with_unicode/input.py
@@ -14,8 +14,8 @@ def problem_chars(self):
         return self._problem_chars
 
 
-def method_withBadName_andParams(my_normal_param, myBadlyNamedParam, my_other_Bad_param):
-    """Provide example where black will want to split out result."""
+def method_with_valid_name(my_normal_param):
+    """Provide with a short, valid name."""
     return 5 + 7
 
 data =   ("device_name, supported_encodings",
diff --git a/tests/test_cli/format_test_cases__snapshots/file_with_unicode/output.diff b/tests/test_cli/format_test_cases__snapshots/file_with_unicode/output.diff
index 218c940a..ed162038 100644
--- a/tests/test_cli/format_test_cases__snapshots/file_with_unicode/output.diff
+++ b/tests/test_cli/format_test_cases__snapshots/file_with_unicode/output.diff
@@ -1,7 +1,7 @@
 --- input.py
 +++ input.py_formatted
 @@ -18,7 +18,9 @@
-     """Provide example where black will want to split out result."""
+     """Provide with a short, valid name."""
      return 5 + 7
 
 -data =   ("device_name, supported_encodings",
diff --git a/tests/test_cli/format_test_cases__snapshots/file_with_unicode/output.py b/tests/test_cli/format_test_cases__snapshots/file_with_unicode/output.py
index ea2d139d..09c95dea 100644
--- a/tests/test_cli/format_test_cases__snapshots/file_with_unicode/output.py
+++ b/tests/test_cli/format_test_cases__snapshots/file_with_unicode/output.py
@@ -14,8 +14,8 @@ def problem_chars(self):
         return self._problem_chars
 
 
-def method_withBadName_andParams(my_normal_param, myBadlyNamedParam, my_other_Bad_param):
-    """Provide example where black will want to split out result."""
+def method_with_valid_name(my_normal_param):
+    """Provide with a short, valid name."""
     return 5 + 7
 
 

From 809acbd6e0d9f5c4f82dc7205d7cf6b979db2fe0 Mon Sep 17 00:00:00 2001
From: mshafer-NI <23644905+mshafer-NI@users.noreply.github.com>
Date: Wed, 12 Nov 2025 16:41:50 -0600
Subject: [PATCH 07/10] clean up changes some

---
 ni_python_styleguide/_fix.py                 | 11 ++++++-----
 ni_python_styleguide/_utils/code_analysis.py |  4 +++-
 2 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/ni_python_styleguide/_fix.py b/ni_python_styleguide/_fix.py
index dd0d8db3..f039790d 100644
--- a/ni_python_styleguide/_fix.py
+++ b/ni_python_styleguide/_fix.py
@@ -1,5 +1,6 @@
 import logging
 import pathlib
+import shutil
 import typing
 from collections import defaultdict
 from typing import Iterable
@@ -21,7 +22,7 @@
 
 
 def _sort_imports(file: pathlib.Path, app_import_names):
-    raw = file.read_text(encoding="utf-8")
+    raw = file.read_text(encoding=_utils.DEFAULT_ENCODING)
     isort_config = isort.Config(
         settings_file=str(_config_constants.ISORT_CONFIG_FILE),
         known_first_party=filter(None, app_import_names.split(",")),
@@ -30,7 +31,7 @@ def _sort_imports(file: pathlib.Path, app_import_names):
         raw,
         config=isort_config,
     )
-    file.write_text(output, encoding="utf-8")
+    file.write_text(output, encoding=_utils.DEFAULT_ENCODING)
 
 
 def _format_imports(file: pathlib.Path, app_import_names: Iterable[str]) -> None:
@@ -117,13 +118,13 @@ def fix(
                     )
             else:
                 with temp_file.multi_access_tempfile(suffix="__" + bad_file.name) as working_file:
-                    working_file.write_text(bad_file.read_text(encoding="utf-8"), encoding="utf-8")
+                    shutil.copyfile(bad_file, working_file)
                     _format.format(working_file, "-q")
                     _format_imports(file=working_file, app_import_names=app_import_names)
 
                     diff_lines = better_diff.unified_plus.format_diff(
-                        bad_file.read_text(encoding="utf-8"),
-                        working_file.read_text(encoding="utf-8"),
+                        bad_file.read_text(encoding=_utils.DEFAULT_ENCODING),
+                        working_file.read_text(encoding=_utils.DEFAULT_ENCODING),
                         fromfile=f"{_posix_relative_if_under(bad_file, pathlib.Path.cwd())}",
                         tofile=f"{_posix_relative_if_under(bad_file, pathlib.Path.cwd())}_formatted",
                     )
diff --git a/ni_python_styleguide/_utils/code_analysis.py b/ni_python_styleguide/_utils/code_analysis.py
index 5fcaaaeb..25e1c9cb 100644
--- a/ni_python_styleguide/_utils/code_analysis.py
+++ b/ni_python_styleguide/_utils/code_analysis.py
@@ -11,7 +11,9 @@ def find_import_region(file: pathlib.Path) -> Tuple[int, int]:
     file: pathlib.Path path to file to evaluate
     Return: Tuple[int, int] the start and ending lines (0 based) of the module level imports
     """
-    file_contents = file.read_text(encoding="utf-8")
+    file_contents = file.read_text(
+        encoding="utf-8"
+    )  # can't use DEFAULT_ENCODING here due to possible circular imports
     tree = ast.parse(file_contents)
     end = start = 0
     for node in tree.body:  # only walk top level items

From 593db5030d48d3c2a1087dc49a76fef0b180c6e8 Mon Sep 17 00:00:00 2001
From: mshafer-NI <23644905+mshafer-NI@users.noreply.github.com>
Date: Wed, 12 Nov 2025 16:41:53 -0600
Subject: [PATCH 08/10] format

---
 tests/conftest.py | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/tests/conftest.py b/tests/conftest.py
index 84d4eb4c..fd6c02d0 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -8,6 +8,7 @@
 
 from ni_python_styleguide.__main__ import main as styleguide_main
 
+
 def pytest_collection_modifyitems(items):
     """Ignores deprecation warnings in all tests."""
     for item in items:
@@ -67,18 +68,18 @@ def force_ascii_encoding(monkeypatch):
     # Patch pathlib.Path.read_text and write_text to use ASCII when encoding not specified
     original_read_text = pathlib.Path.read_text
     original_write_text = pathlib.Path.write_text
-    
+
     def ascii_read_text(self, encoding=None, errors=None):
         if encoding is None:
-            encoding = 'ascii'
+            encoding = "ascii"
         return original_read_text(self, encoding=encoding, errors=errors)
-    
+
     def ascii_write_text(self, data, encoding=None, errors=None, newline=None):
         if encoding is None:
-            encoding = 'ascii'
+            encoding = "ascii"
         return original_write_text(self, data, encoding=encoding, errors=errors, newline=newline)
-    
-    monkeypatch.setattr(pathlib.Path, 'read_text', ascii_read_text)
-    monkeypatch.setattr(pathlib.Path, 'write_text', ascii_write_text)
+
+    monkeypatch.setattr(pathlib.Path, "read_text", ascii_read_text)
+    monkeypatch.setattr(pathlib.Path, "write_text", ascii_write_text)
 
     yield None

From 519ee162ec675dcfa0b0079a24a9784a52a485dc Mon Sep 17 00:00:00 2001
From: mshafer-NI <23644905+mshafer-NI@users.noreply.github.com>
Date: Wed, 12 Nov 2025 16:48:35 -0600
Subject: [PATCH 09/10] undo adding pytest-mock, not needed yet

---
 poetry.lock    | 21 ++-------------------
 pyproject.toml |  1 -
 2 files changed, 2 insertions(+), 20 deletions(-)

diff --git a/poetry.lock b/poetry.lock
index 626cfb73..f7bd279f 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -1,4 +1,4 @@
-# This file is automatically @generated by Poetry 1.8.3 and should not be changed by hand.
+# This file is automatically @generated by Poetry 1.8.2 and should not be changed by hand.
 
 [[package]]
 name = "better-diff"
@@ -419,23 +419,6 @@ files = [
 click = ">=6.0"
 pytest = ">=5.0"
 
-[[package]]
-name = "pytest-mock"
-version = "3.14.1"
-description = "Thin-wrapper around the mock package for easier use with pytest"
-optional = false
-python-versions = ">=3.8"
-files = [
-    {file = "pytest_mock-3.14.1-py3-none-any.whl", hash = "sha256:178aefcd11307d874b4cd3100344e7e2d888d9791a6a1d9bfe90fbc1b74fd1d0"},
-    {file = "pytest_mock-3.14.1.tar.gz", hash = "sha256:159e9edac4c451ce77a5cdb9fc5d1100708d2dd4ba3c3df572f14097351af80e"},
-]
-
-[package.dependencies]
-pytest = ">=6.2.5"
-
-[package.extras]
-dev = ["pre-commit", "pytest-asyncio", "tox"]
-
 [[package]]
 name = "pytest-snapshot"
 version = "0.9.0"
@@ -512,4 +495,4 @@ files = [
 [metadata]
 lock-version = "2.0"
 python-versions = "^3.8"
-content-hash = "480d0af21c1df570785160169d0a7e89ed92a72f7b5cc4f35251540200a5eeaa"
+content-hash = "a8aef2d773dabdd18223fcb2aabce153b8a4f45750fe636d15acf5b47143ea16"
diff --git a/pyproject.toml b/pyproject.toml
index b7ecd5af..f8dbaa9c 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -56,7 +56,6 @@ pep8-naming = ">=0.11.1"
 pytest = ">=6.0.1"
 pytest_click = ">=1.0.2"
 pytest-snapshot = ">=0.6.3"
-pytest-mock = ">=3.8.1"
 
 [tool.poetry.scripts]
 ni-python-styleguide = 'ni_python_styleguide._cli:main'

From acb8ccae995d49b855b9203f5911e9a2bf8acc26 Mon Sep 17 00:00:00 2001
From: mshafer-NI <23644905+mshafer-NI@users.noreply.github.com>
Date: Wed, 12 Nov 2025 16:57:32 -0600
Subject: [PATCH 10/10] Apply suggestions from code review

---
 tests/conftest.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tests/conftest.py b/tests/conftest.py
index fd6c02d0..f8180add 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -74,10 +74,10 @@ def ascii_read_text(self, encoding=None, errors=None):
             encoding = "ascii"
         return original_read_text(self, encoding=encoding, errors=errors)
 
-    def ascii_write_text(self, data, encoding=None, errors=None, newline=None):
+    def ascii_write_text(self, data, encoding=None, errors=None, **kwargs):
         if encoding is None:
             encoding = "ascii"
-        return original_write_text(self, data, encoding=encoding, errors=errors, newline=newline)
+        return original_write_text(self, data, encoding=encoding, errors=errors, **kwargs)
 
     monkeypatch.setattr(pathlib.Path, "read_text", ascii_read_text)
     monkeypatch.setattr(pathlib.Path, "write_text", ascii_write_text)