Remove duplicate file-mocking boilerplate in loader tests

[Copilot]

• Replace parenthesized with (cm1, cm2, cm3): with nested with statements in file_test.py to fix pylint E1129 (not-context-manager)

[sourcery-ai]

Reviewer's Guide

Refactors loader tests to centralize file-mocking logic in a new LoaderTestBase mixin, which provides a shared mock_file context manager, and updates all loader test classes to use it alongside TestCase so LoaderTestBase itself is no longer collected as a test.

File-Level Changes

Change	Details	Files
Introduce LoaderTestBase mixin providing shared file-mocking context manager for loader tests.	Add LoaderTestBase class that defines a mock_file context manager using patch and mock_open to mock open, os.path.exists, and os.path.isfile. Move OPEN, PATH_EXISTS, and PATH_ISFILE constants alongside the new base class to serve as shared patch targets for all loader tests.	tests/_loaders/file_test.py
Update CSV loader tests to use LoaderTestBase mixin and shared mock_file helper instead of local mocking boilerplate.	Change TestCSVLoader to inherit from LoaderTestBase in addition to TestCase so it gains mock_file while remaining a proper unittest test case. Remove the local mock_csv_file context manager and associated imports in favor of calling self.mock_file in tests. Update all CSV loader tests to call self.mock_file with appropriate content and flags instead of mock_csv_file.	tests/_loaders/test_csv_loader.py
Update XML loader tests to use LoaderTestBase mixin and shared mock_file helper instead of local mocking boilerplate.	Change TestXmlLoader to inherit from LoaderTestBase and TestCase. Remove setUp and the local mock_xml_file context manager plus their supporting imports in favor of the shared mock_file helper. Replace all usages of self.mock_xml_file with self.mock_file, passing the appropriate content argument.	tests/_loaders/test_xml_loader.py
Update YAML loader tests to use LoaderTestBase mixin and shared mock_file helper instead of inline patch/mocking code.	Change TestYamlLoader to inherit from LoaderTestBase and TestCase. Remove direct uses of patch and mock_open and rely on the mock_file context manager to handle file, exists, and isfile mocking for all file-based YAML tests.	tests/_loaders/test_yaml_loader.py
Update JSON loader tests to use LoaderTestBase mixin and shared mock_file helper instead of inline patch/mocking code.	Change TestJsonLoader to inherit from LoaderTestBase and TestCase. Remove direct uses of patch and mock_open and rely on the mock_file context manager to handle file, exists, and isfile mocking for all file-based JSON tests.	tests/_loaders/test_json_loader.py

---

Tips and commands

Interacting with Sourcery

• Trigger a new review: Comment @sourcery-ai review on the pull request.
• Continue discussions: Reply directly to Sourcery's review comments.
• Generate a GitHub issue from a review comment: Ask Sourcery to create an
  issue from a review comment by replying to it. You can also reply to a
  review comment with @sourcery-ai issue to create an issue from it.
• Generate a pull request title: Write @sourcery-ai anywhere in the pull
  request title to generate a title at any time. You can also comment
  @sourcery-ai title on the pull request to (re-)generate the title at any time.
• Generate a pull request summary: Write @sourcery-ai summary anywhere in
  the pull request body to generate a PR summary at any time exactly where you
  want it. You can also comment @sourcery-ai summary on the pull request to
  (re-)generate the summary at any time.
• Generate reviewer's guide: Comment @sourcery-ai guide on the pull
  request to (re-)generate the reviewer's guide at any time.
• Resolve all Sourcery comments: Comment @sourcery-ai resolve on the
  pull request to resolve all Sourcery comments. Useful if you've already
  addressed all the comments and don't want to see them anymore.
• Dismiss all Sourcery reviews: Comment @sourcery-ai dismiss on the pull
  request to dismiss all existing Sourcery reviews. Especially useful if you
  want to start fresh with a new review - don't forget to comment
  @sourcery-ai review to trigger a new review!

Customizing Your Experience

Access your dashboard to:

• Enable or disable review features such as the Sourcery-generated pull request
  summary, the reviewer's guide, and others.
• Change the review language.
• Add, remove or edit custom review instructions.
• Adjust other review settings.

Getting Help

• Contact our support team for questions or feedback.
• Visit our documentation for detailed guides and information.
• Keep in touch with the Sourcery team by following us on X/Twitter, LinkedIn or GitHub.

[sourcery-ai]

Hey - I've left some high level feedback:

• Since LoaderTestBase is intended purely as a mixin, consider renaming it to something like LoaderTestMixin to better communicate its role and avoid confusion with real TestCase subclasses.
• You could add simple type hints to mock_file (e.g., content: str, exists: bool, is_file: bool) to make its expected usage clearer across all loader tests.

Prompt for AI Agents

Please address the comments from this code review:

## Overall Comments
- Since `LoaderTestBase` is intended purely as a mixin, consider renaming it to something like `LoaderTestMixin` to better communicate its role and avoid confusion with real `TestCase` subclasses.
- You could add simple type hints to `mock_file` (e.g., `content: str`, `exists: bool`, `is_file: bool`) to make its expected usage clearer across all loader tests.

---

Sourcery is free for open source - if you like our reviews please consider sharing them ✨

• X
• Mastodon
• LinkedIn
• Facebook

_{Help me be more useful! Please click 👍 or 👎 on each comment and I'll use the feedback to improve your reviews.}

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud