Improve tests

[vjik]

Q	A
Is bugfix?	❌
New feature?	❌
Breaks BC?	❌

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (9df5c36) 100.00% compared to head (9326da1) 100.00%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #161 +/- ## =========================================== Coverage 100.00% 100.00% Complexity 277 277 =========================================== Files 22 22 Lines 728 728 =========================================== Hits 728 728 ```

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[what-the-diff[bot]]

PR Summary

• Reorganized Test Structure The existing test files were rearranged for better readability and maintainability. This involved renaming, moving files, and changing the file structure under the tests/Integration directory. Among these changes, special modifications have been made in tests/ConfigPathsTest.php and tests/IntegrationTestCase.php.

• Addition of New Testing Logic Various new test files were added to the system to validate different implementation scenarios. These test cover functionality of custom parameters, deep recursive merge, file inclusion with double dot in path, merge indexed arrays, handling not found file, recursion depth, and variables substitution.

• Removal of Outdated Files All .merge-plan.php files in tests/TestAsset/configs/ have been removed since they are outdated or not used anymore.

• Renamed and Moved Files Many test files were renamed and moved to more appropriate directories for enhanced readability and navigation. The PR includes a substantial amount of such changes that contributed to enhancing project-encapsulation and providing a streamlined project hierarchy.

The primary value delivered is in terms of improved code quality, increased test coverage, and better maintainability through clearer file organization.