chore: clear remaining ruff lint failures

Adds tests/* per-file ruff ignores for rules that legitimately differ
between test and production code (PLC0415 lazy imports, PLR2004 magic
status codes, ARG001/ARG002 fixture parameters, TC002/TC003 deferred
typing imports, ANN401/ANN202, EM101/TRY003 short literal exceptions
in test routes, N802 for stdlib-style camelCase methods on test fakes
that mirror logging.Handler).

Applies the user-authorised stylistic fixes to production source so
``ruff check src/ tests/`` passes cleanly:

* src/ledgerbase/__init__.py: switch ``os.path`` calls to ``pathlib``
  (PTH100/PTH118/PTH120/PTH112), assign the ValueError message to a
  variable (EM101/TRY003), and drop the commented-out SECRET_KEY line
  (ERA001).
* src/ledgerbase/config.py: drop the ``#!/usr/bin/env python`` shebang
  on this importable, non-executable module (EXE001).

Linter-applied autofixes also tidied a handful of test-file imports
(unused-import, unsorted-imports, manual-from-import, etc.) and ran
``ruff format`` over the test/src trees.

Verified locally: ``ruff check src/ tests/`` is green, ``ruff format
--check src/ tests/`` is green, ``pytest tests/`` passes 72/72 with
95 % line / 87 % branch coverage on the targeted modules.

Author: claude

pyproject.toml

@@ -187,6 +187,34 @@ exclude = [
 # file‑specific overrides
 [tool.ruff.lint.per-file-ignores]
 "annotation_spec.md" = ["E501"]
+"tests/*" = [
+  # Tests legitimately use literal status codes / sizes (200, 422, 7…) so
+  # mandating named constants would just obscure intent.
+  "PLR2004",
+  # Test fixtures often defer imports to inside test bodies (to avoid
+  # collection-time side-effects, to enable monkeypatching, or to keep
+  # test isolation clean). Module-level-only imports don't fit that need.
+  "PLC0415",
+  # Pytest fixtures appear as unused arguments to the test function but
+  # are required for the dependency-injection wiring -- they're "used"
+  # by being requested.
+  "ARG001",
+  "ARG002",
+  # Tests do not need a strict typing-only import block.
+  "TC002",
+  "TC003",
+  # ``pytest.MonkeyPatch`` parameter etc. -- ANN401 is excessive in tests.
+  "ANN401",
+  "ANN202",
+  # Marshmallow ValidationError is constructed in test routes with a
+  # short literal message.
+  "EM101",
+  "TRY003",
+  # Test fakes must mirror the third-party interface they substitute
+  # (e.g. ``logging.Handler.setLevel``) and so cannot be renamed to
+  # snake_case without breaking duck-typing.
+  "N802",
+]
 
 
 [tool.ruff.lint.isort]

src/ledgerbase/__init__.py

@@ -1,4 +1,5 @@
 import os
+from pathlib import Path
 
 from dotenv import load_dotenv
 from flask_sqlalchemy import SQLAlchemy
@@ -35,23 +36,24 @@
 
 def create_app() -> Flask:
     """Application factory function."""
-    project_root = os.path.abspath(os.path.join(os.path.dirname(__file__), ".."))
-    template_dir = os.path.join(project_root, "templates")
+    project_root = Path(__file__).resolve().parent.parent
+    template_dir = project_root / "templates"
 
-    if not os.path.isdir(template_dir):
+    if not template_dir.is_dir():
         print(f"Warning: Template directory not found at {template_dir}")
         app = Flask(__name__)
     else:
-        app = Flask(__name__, template_folder=template_dir)
+        app = Flask(__name__, template_folder=str(template_dir))
 
     app.config["SQLALCHEMY_DATABASE_URI"] = os.getenv(
-        "DATABASE_URL", "sqlite:///default.db"
+        "DATABASE_URL",
+        "sqlite:///default.db",
     )
     if not app.config["SQLALCHEMY_DATABASE_URI"]:
-        raise ValueError("DATABASE_URL environment variable is not set.")
+        msg = "DATABASE_URL environment variable is not set."
+        raise ValueError(msg)
 
     app.config["SQLALCHEMY_TRACK_MODIFICATIONS"] = False
-    # app.config["SECRET_KEY"] = os.getenv("SECRET_KEY", "default-secret-key")
 
     # Initialize core services and middleware
     db.init_app(app)

src/ledgerbase/config.py

@@ -1,4 +1,3 @@
-#!/usr/bin/env python
 """---
 # Front-Matter for Python Module
 

tests/app_factory_test.py

@@ -111,7 +111,8 @@ def test_sentry_dsn_absent_branch_prints_notice(
 ) -> None:
     """Reproduce the ``SENTRY_DSN not found`` notice path without mutating the
     real ``ledgerbase`` package (which would corrupt SQLAlchemy registry state
-    for other tests)."""
+    for other tests).
+    """
     monkeypatch.delenv("SENTRY_DSN", raising=False)
 
     # Mirror the inline branch in ``ledgerbase/__init__.py`` so we cover the

tests/conftest.py

@@ -2,15 +2,17 @@
 
 from __future__ import annotations
 
+from collections.abc import Iterator
 from pathlib import Path
-from typing import TYPE_CHECKING, Iterator
+from typing import TYPE_CHECKING
 
 import pytest
 
 if TYPE_CHECKING:
-    from flask import Flask
     from flask.testing import FlaskClient
 
+    from flask import Flask
+
 
 PROJECT_ROOT = Path(__file__).resolve().parent.parent
 TEMPLATES_DIR = PROJECT_ROOT / "templates"
@@ -29,11 +31,10 @@ def app(monkeypatch: pytest.MonkeyPatch) -> Iterator[Flask]:
 
     monkeypatch.setattr(_ledger_pkg, "configure_logging", lambda _app: None)
 
-    from ledgerbase import create_app, db
-
     # Ensure ``ExampleModel`` is registered against the current ``db.metadata``
     # so ``db.create_all()`` actually creates its table.
     import ledgerbase.models  # noqa: F401
+    from ledgerbase import create_app, db
 
     flask_app = create_app()
     flask_app.config.update(TESTING=True)

tests/error_handlers_full_test.py

@@ -4,7 +4,6 @@
 
 from typing import TYPE_CHECKING
 
-import pytest
 from marshmallow import ValidationError
 from werkzeug.exceptions import InternalServerError, NotFound
 

tests/plaid_service_test.py

@@ -18,7 +18,7 @@
 import pytest
 import requests
 
-import services.plaid_service as plaid_service
+from services import plaid_service
 from services.plaid_service import (
     PLAID_BASE_URLS,
     create_link_token,
@@ -105,7 +105,8 @@ def test_plaid_request_returns_none_on_http_error(
 ) -> None:
     """An HTTP error (e.g. token expiry 401) returns None and prints diagnostics."""
     bad_response = _make_response(
-        {"error_code": "INVALID_ACCESS_TOKEN"}, status_code=401
+        {"error_code": "INVALID_ACCESS_TOKEN"},
+        status_code=401,
     )
     with patch.object(plaid_service.requests, "post", return_value=bad_response):
         result = plaid_request("/endpoint", {"access_token": "expired"})

tests/security_full_test.py

@@ -3,7 +3,6 @@
 from __future__ import annotations
 
 import logging
-from logging.handlers import RotatingFileHandler
 from pathlib import Path
 from typing import TYPE_CHECKING
 
@@ -102,7 +101,8 @@ def test_configure_logging_skips_setup_in_testing_mode() -> None:
 
 
 def test_configure_logging_attaches_file_handler_in_production(
-    monkeypatch: pytest.MonkeyPatch, tmp_path: Path
+    monkeypatch: pytest.MonkeyPatch,
+    tmp_path: Path,
 ) -> None:
     """Non-debug, non-test apps get a RotatingFileHandler installed."""
     import ledgerbase.security as security_mod