Design an Account struct with fields for ID, owner name, and balance. Consider what data types are appropriate for each field.
Think about what can go wrong in banking operations: insufficient funds, invalid amounts, account not found, etc. Create custom error types for these scenarios.
Implement the error interface by creating a struct with an Error() string method. Include relevant context in your error messages.
Always validate inputs before performing operations. Check for negative amounts, nil pointers, and other invalid conditions.
For withdrawal operations, check if the account has sufficient funds before modifying the balance. Return an appropriate error if not.
Use sync.Mutex to protect account operations from race conditions when multiple goroutines access the same account.
Use fmt.Errorf with the %w verb to wrap errors and provide additional context while preserving the original error.
Write tests that verify both successful operations and error conditions. Use type assertions to check for specific error types.