Refactor tests for clarity and maintainability

[Rian-Ismael]

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Summary of changes:

Enhances the overall quality of the test code by addressing structural and readability issues.

Eliminates redundant assertions by splitting responsibilities into more focused test cases, improving test isolation and debuggability. Replaces raw numeric literals with descriptive constants, increasing clarity and making the test logic easier to understand and maintain.

These improvements contribute to more robust and maintainable test suites without changing existing behavior.