feat: implement CreditLineData storage keyed by borrower

[iammrjude]

Fixes #2 · Closes #2

Summary

Implements persistent storage for CreditLineData keyed by borrower Address. Each borrower now has a single credit line record that can be read and updated by all contract methods through dedicated storage helper functions.

Changes

contracts/credit/src/types.rs

• Added last_update_timestamp: u64 field to CreditLineData for future interest accrual calculations

contracts/credit/src/lib.rs

• Added get_credit_line_data storage helper — retrieves CreditLineData from persistent storage by borrower Address, returns None if not found
• Added set_credit_line_data storage helper — writes CreditLineData to persistent storage keyed by borrower Address, overwrites any existing record
• Refactored all contract methods to use the new helpers instead of raw storage calls
• open_credit_line now sets last_update_timestamp on creation
• draw_credit and repay_credit now update last_update_timestamp on every state change

Tests

Added mod test_credit_line_storage covering:

• Missing key returns None
• Storage write and read correctness across all fields
• Overwrite replaces existing record correctly
• Isolation between borrowers — modifying one does not affect the other
• last_update_timestamp field is set and readable on open

Test Output

$ cargo test test_credit_line_storage
    Finished `test` profile [unoptimized + debuginfo] target(s) in 0.39s
     Running unittests src\lib.rs (target\debug\deps\creditra_credit-3834f56052e6a3bb.exe)

running 5 tests
test test_credit_line_storage::test_storage_returns_none_for_missing_borrower ... ok
test test_credit_line_storage::test_storage_last_update_timestamp_set_on_open ... ok
test test_credit_line_storage::test_storage_write_and_read_credit_line ... ok
test test_credit_line_storage::test_storage_overwrite_updates_record ... ok
test test_credit_line_storage::test_storage_isolation_between_borrowers ... ok

test result: ok. 5 passed; 0 failed; 0 ignored; 0 measured; 65 filtered out; finished in 0.06s

cargo test

$ cargo test
   Compiling creditra-credit v0.1.0 (C:\Users\jude\stellar_projects\Creditra-Contracts\contracts\credit)
    Finished `test` profile [unoptimized + debuginfo] target(s) in 6.27s
     Running unittests src\lib.rs (target\debug\deps\creditra_credit-3834f56052e6a3bb.exe)

running 70 tests
test test::test_default_credit_line ... ok
test test::test_close_nonexistent_credit_line - should panic ... ok
test test::test_close_credit_line ... ok
test test::test_close_credit_line_idempotent_when_already_closed ... ok
test test::test_close_credit_line_borrower_when_utilized_zero ... ok
test test::test_close_credit_line_borrower_rejected_when_utilized_nonzero - should panic ... ok
test test::test_close_credit_line_unauthorized_closer - should panic ... ok
test test::test_close_credit_line_admin_force_close_with_utilization ... ok
test test::test_default_nonexistent_credit_line - should panic ... ok
test test::test_default_credit_line_unauthorized - should panic ... ok
test test::test_draw_cumulative_exceeds_limit - should panic ... ok
test test::test_draw_exceeds_credit_limit - should panic ... ok
test test::test_draw_negative_amount_fails - should panic ... ok
test test::test_draw_accumulates_across_multiple_draws ... ok
test test::test_draw_no_credit_line_fails - should panic ... ok
test test::test_draw_exact_credit_limit ... ok
test test::test_draw_on_defaulted_line_fails - should panic ... ok
test test::test_draw_on_suspended_line_fails - should panic ... ok
test test::test_draw_reduces_contract_reserve ... ok
test test::test_draw_on_closed_line_fails - should panic ... ok
test test::test_draw_updates_utilized_amount ... ok
test test::test_draw_transfers_correct_amount_to_borrower ... ok
test test::test_draw_zero_amount_fails - should panic ... ok
test test::test_draw_requires_borrower_auth ... ok
test test::test_event_default_credit_line ... ok
test test::test_event_close_credit_line ... ok
test test::test_event_open_credit_line ... ok
test test::test_init_and_open_credit_line ... ok
test test::test_event_suspend_credit_line ... ok
test test::test_event_lifecycle_sequence ... ok
test test::test_full_lifecycle ... ok
test test::test_open_credit_line_negative_limit_reverts - should panic ... ok
test test::test_open_credit_line_interest_rate_exceeds_max_reverts - should panic ... ok
test test::test_open_credit_line_risk_score_exceeds_max_reverts - should panic ... ok
test test::test_open_credit_line_duplicate_active_borrower_reverts - should panic ... ok
test test::test_open_credit_line_zero_limit_reverts - should panic ... ok
test test::test_repay_credit_nonexistent_line - should panic ... ok
test test::test_repay_credit_rejects_non_positive_amount - should panic ... ok
test test::test_multiple_borrowers_draw_independently ... ok
test test::test_repay_credit_rejected_when_closed - should panic ... ok
test test::test_reentrancy_guard_cleared_after_draw ... ok
test test::test_reentrancy_guard_cleared_after_repay ... ok
test test::test_suspend_credit_line ... ok
test test::test_suspend_nonexistent_credit_line - should panic ... ok
test test::test_repay_credit_reduces_utilized_amount ... ok
test test::test_suspend_credit_line_unauthorized - should panic ... ok
test test::test_repay_credit_saturates_at_zero ... ok
test test::test_update_risk_parameters_interest_rate_exceeds_max - should panic ... ok
test test::test_update_risk_parameters_nonexistent_line - should panic ... ok
test test::test_update_risk_parameters_at_boundaries ... ok
test test::test_update_risk_parameters_negative_credit_limit - should panic ... ok
test test::test_update_risk_parameters_unauthorized_caller - should panic ... ok
test test::test_update_risk_parameters_success ... ok
test test::test_update_risk_parameters_credit_limit_below_utilized - should panic ... ok
test test::test_update_risk_parameters_risk_score_exceeds_max - should panic ... ok
test test_close_utilized::test_close_utilized_admin_force_close_emits_closed_event ... ok
test test_close_utilized::test_close_utilized_admin_force_close_multiple_draws ... ok
test test_close_utilized::test_close_utilized_admin_force_close_preserves_utilized_amount ... ok
test test_close_utilized::test_close_utilized_borrower_rejected_at_full_utilization - should panic ... ok
test test_close_utilized::test_close_utilized_borrower_rejected_on_suspended_line - should panic ... ok
test test_close_utilized::test_close_utilized_borrower_rejected_after_partial_repayment - should panic ... ok
test test_close_utilized::test_close_utilized_borrower_rejected_at_minimum_utilization - should panic ... ok
test test_close_utilized::test_close_utilized_admin_force_close_suspended_line ... ok
test test_close_utilized::test_close_utilized_third_party_rejected_with_zero_utilization - should panic ... ok
test test_credit_line_storage::test_storage_returns_none_for_missing_borrower ... ok
test test_credit_line_storage::test_storage_last_update_timestamp_set_on_open ... ok
test test_credit_line_storage::test_storage_overwrite_updates_record ... ok
test test_credit_line_storage::test_storage_write_and_read_credit_line ... ok
test test_credit_line_storage::test_storage_isolation_between_borrowers ... ok
test test_close_utilized::test_close_utilized_borrower_succeeds_after_full_repayment ... ok

test result: ok. 70 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 1.40s

   Doc-tests creditra_credit

running 0 tests

test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s

[iammrjude]

@greatest0fallt1me Done Boss

[greatest0fallt1me]

please resolve the conflicts

[greatest0fallt1me]

@iammrjude Can you resolve the conflicts?