Refactor test cases for improved readability and consistency

- Updated test functions in various test files to enhance code clarity by formatting long lines and improving indentation.
- Adjusted assertions to use multi-line formatting for better readability.
- Added new test cases for theme settings API to ensure proper functionality.
- Ensured consistent use of line breaks and spacing across test files for uniformity.

models/__init__.py

@@ -2,5 +2,9 @@
 models package initializer. Import key models so they're registered
 with the shared Base.metadata when the package is imported by tests.
 """
+
 from . import application_setting  # noqa: F401
 from . import currency  # noqa: F401
+from . import role  # noqa: F401
+from . import user  # noqa: F401
+from . import theme_setting  # noqa: F401