Deliverable 6

  
  address private _notary;
  Loan[] private _availableLoans;
  uint8 private _numLoans;
  mapping(address => bool) private _scoreInitialized;
  mapping(address => uint) public _creditScores;
  mapping(address => uint) private _scoreTimestamps;

  constructor() {
    _notary = msg.sender;
  }

 function getScore(address client, uint amountRequested) public view returns (uint) {

    // Version 1, no encryption of scores
    // return _creditScores[client].score;

    // Adjust the score based on the amountRequested
    uint baseScore = _creditScores[client];

    uint adjustedScore = baseScore - (amountRequested / 100); // Decrease score by 1 for every 100 units requested

    return adjustedScore;  }

function testGetScore() public {
        address client = address(0x123);
        uint initialScore = 750; 
        uint amountRequested = 500; 
        
        cbsc._creditScores[client] = initialScore;
        
        uint adjustedScore = cbsc.getScore(client, amountRequested);
        
        uint expectedScore = initialScore - (amountRequested / 100); // Expected adjusted score
        
        Assert.equal(adjustedScore, expectedScore, "Adjusted score should be calculated correctly based on the amount requested");
    }

    function testGetScoreWithZeroAmountRequested() public {
        address client = address(0x123);
        uint initialScore = 750;
        uint amountRequested = 0;
        
        cbsc._creditScores[client] = initialScore;
        
        uint adjustedScore = cbsc.getScore(client, amountRequested);
        
        Assert.equal(adjustedScore, initialScore, "Adjusted score should remain unchanged when zero amount is requested");
    }

The updateScoreBorrow(uint amount):function: This function updates the credit score of the borrower when a loan is taken. It decreases the credit score based on the borrowed amount, ensuring it doesn't fall below a minimum threshold (300 in this case). Finally, it subtracts the borrowed amount from the credit score of the borrower.

      function updateScoreBorrow(uint amount) public {
    uint baseScore = _creditScores[tx.origin];

   
    uint scaledAmount = amount / 100;
    uint scaledScore = baseScore - scaledAmount;

    if (scaledScore < 300) {
        scaledScore = 300;
    }

    _creditScores[tx.origin] = scaledScore;
      _creditScores[tx.origin] -= amount;
  }

Testing the borrow(uint amount) function: To write test cases for this function, we'll cover various scenarios to ensure its correctness. Here are some scenarios:

• Test to ensure borrower can't borrow twice.
• Test case to ensure borrower can't borrow more than total amount available.

function testUpdateScoreBorrow() public {
=        address borrower = msg.sender; 
        uint initialScore = 750; 
        uint borrowedAmount = 500; 
        
        // Set the initial credit score of the borrower
        yourContract._creditScores[borrower] = initialScore;
        
        // Call the function to be tested
        cbsc.updateScoreBorrow(borrowedAmount);
        
        // Retrieve the updated credit score of the borrower
        uint updatedScore = cbsc._creditScores[borrower];
        
        // Calculate the expected updated score
        uint expectedScore = initialScore - (borrowedAmount / 100); // Expected updated score
        
        // Assert that the updated score is calculated correctly
        Assert.equal(updatedScore, expectedScore, "Updated score should be calculated correctly based on the borrowed amount");
    }

The updateScoreRepayment(uint amount) function: This function updates the credit score of the borrower when a repayment is made. It increases the credit score based on the repayment amount, ensuring it doesn't exceed the maximum threshold (850 in this case). Finally, it updates the credit score of the borrower with the scaled score.

function updateScoreRepayment(uint amount) public {
    uint baseScore = _creditScores[tx.origin];


    uint scaledAmount = amount / 100;
    uint scaledScore = baseScore + scaledAmount;

    if (scaledScore > 850) {
        scaledScore = 850;
    }

    _creditScores[tx.origin] = scaledScore;
  }

Testing the updateScoreRepayment() function: Verifies that the function updates the credit score of the borrower correctly according to the provided repayment amount and constraints (such as not exceeding the maximum threshold).

• Test case to ensure interest calculation is correct when numPayments is greater than 0.

function testUpdateScoreRepayment() public {
        // Set up initial conditions
        address borrower = address(0x123); // Address of the borrower
        uint initialScore = 750; // Initial credit score of the borrower
        uint repaymentAmount = 500; // Amount to be repaid
        
        cbsc._creditScores[borrower] = initialScore;
        
        // Call the function to be tested
        cbsc.updateScoreRepayment(repaymentAmount);
        
        // Retrieve the updated credit score of the borrower
        uint updatedScore = cbsc._creditScores[borrower];
        
        // Assert that the credit score is updated correctly
        uint expectedScore = initialScore + (repaymentAmount / 100); // Expected credit score after repayment
        uint maxScore = 850; // Maximum credit score allowed
        Assert.isAtMost(updatedScore, maxScore, "Credit score should not exceed maximum threshold");
        Assert.equal(updatedScore, expectedScore, "Credit score should be updated correctly after repayment");
    }

Deploying the Smart Contract:

References:

[1] T. H. Austin, K. Potika and C. Pollett, 'Autonomous Lending Organization on Ethereum with Credit Scoring,' 2023 Silicon Valley Cybersecurity Conference (SVCC), San Jose, CA, USA, 2023.