feat: Test/fees structure and user volume

[Anuoluwapo25]

Pull Request Template

📝 Description

This PR adds comprehensive unit tests for the fee structure and user transaction volume logic in the Soroban smart contract.

🎯 Type of Change

• Bug fix
• [] New feature
• [] Breaking change
• Documentation update
• [] Refactoring
• [] Performance improvement
• [] Security enhancement
• Other (please describe):

🔧 Changes Made

Files Modified

• src/test_fees.rs

New Files Added

• src/test_fees.rs (if it did not exist before)

Files Modified

Added tests for get_fee_structure across all FeeType variants

Added tests validating fee structure updates

Added tests for get_user_volume_data with zero initial state

Added tests for update_user_transaction_volume behavior

Added tests validating volume tier boundaries

Ensured coverage across edge cases and boundary conditions

New Files Added

Key Changes

🧪 Testing

• Unit tests pass
• Integration tests pass
• Manual testing completed
• No breaking changes introduced
• Cross-platform compatibility verified
• Edge cases tested

Test Coverage

Fee Structure

Retrieve fee structure for each FeeType

Verify values after updating fee configuration

Validate correct storage and retrieval behavior

User Volume Data

Initial state returns zero transaction volume

After update_user_transaction_volume, volume updates correctly

Retrieval via get_user_volume_data returns expected values

Volume Tier Boundaries

Tests at exact boundary values

Tests just below tier thresholds

Tests just above tier thresholds

📋 Contract-Specific Checks

• Soroban contract builds successfully
• WASM compilation works
• [] Gas usage optimized
• Security considerations reviewed
• [] Events properly emitted
• Contract functions tested
• Error handling implemented
• Access control verified

Contract Testing Details

📋 Review Checklist

• Code follows project style guidelines
• Documentation updated if needed
• No sensitive data exposed
• Error handling implemented
• Edge cases considered
• Code is self-documenting
• No hardcoded values
• Proper logging implemented

🔍 Code Quality

• Clippy warnings addressed
• Code formatting follows rustfmt standards
• No unused imports or variables
• Functions are properly documented
• Complex logic is commented

🚀 Performance & Security

• Gas optimization reviewed
• No potential security vulnerabilities
• Input validation implemented
• Access controls properly configured
• No sensitive information in logs

📚 Documentation

• README updated if needed
• Code comments added for complex logic
• API documentation updated
• Changelog updated (if applicable)

🔗 Related Issues

Closes #347
Fixes #347

📋 Additional Notes

🧪 How to Test

1. Clone the repository
2. Checkout the branch "git checkout test/fee-structure-volume-data"
3. Run tests "cargo test"
4. Verify that all tests pass and coverage meets the required threshold.

📸 Screenshots (if applicable)

⚠️ Breaking Changes

🔄 Migration Steps (if applicable)

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📋 Reviewer Checklist

Code Review

• Code is readable and well-structured
• Logic is correct and efficient
• Error handling is appropriate
• Security considerations addressed
• Performance impact assessed

Contract Review

• Contract logic is sound
• Gas usage is reasonable
• Events are properly emitted
• Access controls are correct
• Edge cases are handled

Documentation Review

• Code is self-documenting
• Comments explain complex logic
• README updates are clear
• API changes are documented

Testing Review

• Tests cover new functionality
• Tests are meaningful and pass
• Edge cases are tested
• Integration tests work correctly