How did you test payment systems? How did you run transactions?

Testing payment systems requires special attention to security, accuracy, and stability. I usually use the following approaches:

• Test environments and sandboxes: Working with test accounts and APIs of payment providers that simulate real transactions without deducting money.
• Automation of transactions: Writing scripts or autotests that create transactions with different parameters — amounts, currencies, payment methods, statuses (successful, declined, canceled).
• Error handling checks: Simulating network errors, provider failures, incorrect data to test system resilience.
• Monitoring and logging: Analyzing logs and metrics to ensure transactions are processed correctly and on time.

Here's a simple example of an autotest in JavaScript using axios to send a payment in a test environment:

const axios = require('axios');

async function testPayment() {
  try {
    const response = await axios.post('https://sandbox.paymentprovider.com/api/pay', {
      amount: 1000,
      currency: 'USD',
      cardNumber: '4111111111111111',
      expiry: '12/25',
      cvv: '123'
    });
    console.log('Payment status:', response.data.status);
  } catch (error) {
    console.error('Payment error:', error.message);
  }
}

testPayment();

This way, transactions can be run automatically, testing different scenarios.