test: improve e2e test coverage and documentation

[MozirDmitriy]

Improve E2E Test Coverage and Documentation

Overview

This pull request enhances the end-to-end test suite by improving error handling, adding documentation, and refactoring code for better maintainability.

Changes

• Documentation Enhancements:

  • Added detailed comments for each test function to describe their purpose and functionality.
  • Improved error messages for environment variable parsing to provide clearer feedback.

• Code Refactoring:

  • Introduced constants for frequently used values such as TEST_PRIVATE_KEY and DEFAULT_DELEGATION_ADDRESS to improve code readability and maintainability.
  • Refactored the assert_chain_advances test to use a single provider instance and added a more informative assertion message.

• Test Improvements:

  • Enhanced the test_wallet_api to include more descriptive assertions and comments.
  • Added comments to the test_withdrawal_proof_with_fallback to clarify the test logic and expected outcomes.

Benefits

• Improved code readability and maintainability through the use of constants and detailed comments.
• Enhanced error handling and feedback for environment variable parsing.
• Clearer test logic and assertions, making it easier for future contributors to understand and extend the test suite.

Testing

• All tests have been run locally and pass successfully.
• No changes to the core functionality, ensuring backward compatibility.

Related Issues

• N/A