Payment gateway testing: A guide to testing methods for ecommerce

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Nick Knuppe
Head of Product Marketing
Customer-centric marketer, fanatical about GTM.

Platform functionality and online security are critical to the ecommerce sales cycle, and payment gateway testing is essential for any business to provide a smooth payment experience.

What is a test payment gateway?

A test gateway is simply a testing area where ecommerce developers can troubleshoot the setup of a payment system on a website. Think of it as the sandbox web developers use. In this private space, it’s possible to test functionality and identify possible bugs without making real-time transactions.

What does a payment gateway do?

The payment gateway is often described as a virtual ‘gate’. Any transactions made on an ecommerce site must go through the gate as part of the payment process. The payment gateway itself is an online transaction service that an ecommerce retailer uses so that they can accept credit card and debit card payments.

Where does the payment gateway fit into the ecommerce ecosystem?

Payment gateways are usually built into the final checkout page on the website. After customers have supplied their billing and shipping information, they are prompted for their payment details and must then click to initiate the payment. Most payment gateways encrypt the data, so the customer’s private information remains protected while their payment is authorised. 

Difference between a payment gateway and payment processors

People tend to use the terms gateways and processors interchangeably, but they are technically different. A payment gateway is a tool that approves or declines transactions between you and your customers. A payment processor completes the transaction.

What is the difference between a live and a test payment gateway?

The critical difference between a live gateway and a testing gateway is that a live gateway is activated on the live website, while the test payment gateway simulates live transactions. Therefore, no actual payments can be taken when working on a test payment gateway.

Key terms: Talking about payment gateways

  • Business/business owner: A person or company that sells products or services.

  • Credit Card: A physical card linked to a credit account that can be used to buy products or services. It has a 16-digit card number, an expiration date, magnetic stripe, signature panel, a card verification value (CVV) number, and other security features to prevent fraud.

  • Acquiring Bank: A financial institution that maintains your business bank account. It enables you to accept and process debit and/or credit card transactions.

  • Issuing Bank: The financial institution associated with your customer’s debit or credit card. The issuing bank either approves or declines transactions based on the account information and cardholder’s standing and provides that information to the acquiring bank.

  • Transaction: An end-to-end process between a customer and the business exchanging funds.

  • Authorisation: A request to the customer’s issuing bank to hold funds. The bank confirms the cardholder’s validity and their ability to pay. It then deducts the funds from the customer’s credit limit. At this point, the funds are confirmed but not yet transferred to the acquiring bank.

  • Capture: The business collects payment information and sends a settlement (or capture) request to the processor. The processor then initiates the fund transfer between banks.

Why do we need to test payment gateways?

The payment gateway is critical for the functionality of your ecommerce business and the security of your customers. In addition, you can use software testing to ensure that all participating users, including financial institutions, operate together seamlessly.

You need to test the system you adopt for your online business to confirm that you can approve transactions and authorise orders. This also offers many online companies an opportunity to test use-cases and make sure your chosen payment processor meets expectations. If a payment gateway or processor is buggy during the testing phase, you might look into alternative providers.

What are the types of payment gateway tests?

There are four common types of testing:

Functional tests

​​Functional testing makes sure that the application behaves as expected. Test placing orders, confirming correct calculations for multiple items, offer codes, and tax estimations.

Integration tests

Integration testing is crucial when working with a payment gateway. You can use tests to verify that the integration on your ecommerce platform is working properly with your chosen payment gateways. This goes beyond functional testing because it helps verify the placement of orders, checks if funds are received in the account, and allows testing of voided and refunded transactions.

Performance tests

You can run performance tests by having multiple users interact with your online store. However, hosting numerous users may put a strain on an inadequate processor. In addition, the payment processor should not fail if multiple users try to complete transactions simultaneously.

Security tests

When shopping, visitors need to be confident that their sensitive information – like credit card numbers remains secure. These tests will help confirm encryption and data security.

How do you test payment scenarios?

There’s more to payment gateway testing than understanding quality assurance. Having the correct information from the start will streamline testing scenarios, challenge the tools, and increase what you can learn from your tests. Before your team begins testing in a payment processor sandbox, confirm that the following resources and data are structured within your framework:

  • User test data, such as dummy credit card details for all commonly used vendors, including MasterCard, Visa, and the other payment methods and card schemes your customers prefer

  • Payment gateway information, such as Paypal or other integrations

  • Payment gateway document with known error codes

  • Session and parameters for the application

  • Query and variable information 

  • The language of the application

  • The various settings, including currency format, and management of subscriber data collected

​How to test payment gateways: checklist and test cases

Like any other application, testing payment processors and integrating a payment gateway for an ecommerce site involves proper planning.

You can use the following checklist as a reference to make sure your running effective tests:

  • Set up a testing area, or payment processor sandbox

  • Gather test data including dummy test credit card information

  • Get access to backend databases, such as CRM systems or transaction applications

  • Test the following actions:

    • The behaviour of the application when a successful payment is received 

    • Routing a user to a confirmation page after a successful transaction

    • Confirmation of a successful transaction by a secondary communication, usually delivered by email and/or text message

    • Check what happens if a payment fails or if the payment processor stops responding. Note any error codes.

    • Verify behaviour with browser pop-up blockers on and off. This may be helpful if any confirmation messages are being displayed as a pop-up window.

    • Verify different fraud prevention/security settings; for example, see what happens when the customer billing information used in the transaction does not match the data on the dummy account, or if the expiry date on the credit card is incorrect.

    • Verify the transaction flow and how the order history sorts into your database

    • Check what happens when a customer session expires

    • Check for console errors

    • Test usability with different processors and controllers

    • Verify that the transaction is done on a secure channel; for example, secure checkout pages should always use 'https://'

    • Verify that the payment processor currency is correct; the payment processor should be set up to accept the correct form of currency

    • Verify refund functionality. The refunded transaction or voided amount should exceed the transaction amount

What are the best ways to test a payment gateway?

The best online payment systems are tested constantly to identify errors. Consider the following best practices when implementing a payment gateway: 

Combine manual and automated tests

Comprehensive testing of a payment gateway marries manual and automated testing.

Automated testing is helpful for analysing variables like location identifiers, postage and tax calculations, and currency conversion rates to verify accuracy. Automation also simplifies reporting, which developers can interpret to make corrections.

Manual tests done by people are best for reporting actual user experiences when navigating an ecommerce platform and attempting to make online purchases. Manual testing on real devices allows close review of site responsiveness, speed of use, O/S and device compatibility, and experiential challenges that can help problem solve for ecommerce platforms that have perceived errors.

Apply multiple integration tests

It’s always better to run several tests before launching an ecommerce site, and re-test any time that you make changes that may affect usability and core functionality.

Not only does the gateway need to be bug-free, but connections need to be reliable at all times. Updates that should always trigger a re-test include adjustments to the payment page, changes to any region-based data (such as tax rates or shipping information), and data changes that may impact transaction records.

Adopt a scalable testing platform

Platform testing requires a mix of software, testers, and service, and when new testing is required, teams need to leap into action. Most small- to medium-sized ecommerce businesses don’t need regular maintenance, so using a scalable testing platform can be useful to employ as your business grows.

Some test cycles may be longer and more complicated than others .Having a scalable team that can adjust as needed helps you overcome growing pains and allows you to consult with experts that can make it easier to evolve and adapt.

Run a pre-test pilot

A pre-test pilot can safeguard against delays in the long run. A pilot test approach allows an ecommerce site to test parameters and design to be assessed (and even re-designed if necessary). If there’s a significant issue with the payment gateway, early testing can help identify problems and give the team time to make corrections early in development. 

Test for user experience

The end user needs to have the best, most seamless experience of all, so consider the customer's point of view throughout the process.

Prioritising the user interface functionality and user experience can help uncover issues in navigation, pinpoint barriers in an overcomplicated process, and troubleshoot problems like invalid error codes or shopping cart timeouts. Unfortunately, many users abandon their carts when shopping online because of frustrations like these.

Mollie as your gateway provider

At Mollie, our aim is to help all businesses to grow. We do that by delivering an effortless payment solution that offers a seamless checkout and multiple payment methods to boost conversion. When you sign up with Mollie, you’ll also get local support, real-time business insights and reports, and an extensive range of more than 120 powerful plugins for your business. Find out more about payments with Mollie.

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