Mocking Technique

Testing code that depends on external services, configurations, or has side effects can be challenging. Mocking is a powerful technique that simulates the behavior of complex real-world interactions within tests without their complexity and unpredictability.

For instance, if you need to test a money exchange service, one option could involve using your own funds to simulate transactions and observe the outcomes. However, this method can be risky and costly. A more efficient and risk-free alternative is to use mocking to emulate the process of sending money.

Testing a Money Transfer Service

The Testing Approach:

1. Mock the Account Balances: use mocking to simulate different account states, such as insufficient funds or ample funds, to test how the transfer method responds;
2. Verify Transactions: confirm that the appropriate amounts are debited and credited from the respective accounts during a transfer;
3. Handle Exceptions: ensure that the method correctly handles scenarios where the transfer cannot be completed.