Testing: A key factor in the successful migration of payment platforms

In the context of CV platform migration, testing payment processes is a central challenge. This article highlights the key aspects of testing SEPA payments during migration projects – covering our approach, common issues, and best practices to ensure the highest possible level of security and confidence in the target process.

Framework conditions are predictable, but remain unavoidable

The smooth processing of payment transactions is crucial for both companies and private bank customers*, and it poses significant challenges for banks and payment service providers (PSPs) – particularly during platform migrations, such as moving to a new core system after merger or while standardizing processes across regions or units. Since testing is a critical and extensive topic, this article will focus on validating the end-to-end (E2E) processes for SEPA payments.

Migration projects typically involve both internal and external challenges. These include evolving regulatory requirements, standard software releases, and the coordination of testing activities with internal and external stakeholders (e.g. software vendors and clearing partners). These factors influence the entire test cycle, from planning to production.

In the following discussion, we identify key challenges and outline best practices based on practical experience.

E2E test marathon: Mastering challenges with strategy

Test planning begins with the identification of E2E testing needs. Unlike projects where tests are carried out against a fixed specification or business concept, migration requires the selection and testing of a large number of existing processes. The focus is on identifying the critical processes to ensure all key aspects of the migration are covered.
This planning is carried out in close coordination with the bank's experts and is based on the findings from GAP analysis workshops (as detailed in article on "GAP analysis and target image design" published on 27 June 2025).

Preparation and execution of the E2E tests require careful coordination of test case chains and collaboration with external partners – an area which requires special attention. To overcome these complexities, we’ve outlined best practices and approaches.

1. Challenge: Scope expansion after the planning and analysis phase.
   During test preparation and execution, it often becomes apparent that certain business constellations—such as rarely used clearer rejects or objects – were not identified as relevant during the analysis phase. This can lead to unforeseen extensions of the test scope and thus to additional effort.
   
   Approach: To overcome this challenge, we recommend integrating the test stream in the project discussions from the outset. The review of the test concept by the stakeholders responsible is crucial to ensure that all relevant aspects are covered. If any new gaps are discovered during testing, it is important to inform the business analysis experts and project managers immediately. This speeds up the solution development process and minimizes the impact on the test plan.
   
   When testing with external partners, such as the Bundesbank or bilateral clearing partners, it is useful to compare the current test scope with that of previous test cycles. This can be used to determine what has already been tested, which processes and test cases were critical, and where errors occurred. Based on this comparison, it can be decided whether additional test cases should be included in the current test scope or existing ones can be reused.
   
   
   
2. Challenge: Availability of internal key resources and subject matter experts.
   Internal key resources and subject matter experts in payment transactions are often limited due to parallel projects. However, these experts are crucial for validating both test cases and test case chains, ensuring that the entire test scope aligns with the business requirements. Inadequate resource planning can lead to delays in test preparation and execution.
   
   Approach: The subject matter experts should already be involved in the planning and analysis phase. Coordinating deadlines for the release of test preparation documents, such as test concept, test case matrix, test case catalog, etc., with the dates for software releases and regulatory requirements allows for efficient use of resources and helps avoid work overload.
   
   Delegation and prioritization of non-critical tasks can also help minimize resource conflicts, but should be coordinated with project management in advance. From our experience, regular status meetings or jour fixes can be used to release important test documentation. Possible delays due to the limited availability of central resources should be forwarded to the (project) management at an early stage and support should be requested, whenever required.
   
   
   
3. Challenge: Variety of test environments.
   Many internal peripheral systems involved in E2E testing have their own test environments, where maintenance work and new releases often occur in parallel. These activities can interfere with test cycles. For example, maintenance may lead to system failures or data deletion, which in turn requires tests to be restarted.
   
   Additionally, the system settings used by the clearing partners often differ from the production settings, which can cause unexpected processing problems at the start of a test. In some places, this may require a reconfiguration of the testing infrastructure between the bank and the clearing partner, leading to additional preparation time.
   
   Approach: Test plans should be coordinated with both the ZV platform team and those overseeing the bank's internal peripheral systems to ensure all technical dependencies are considered. Regular exchange with the relevant peripheral systems is recommended to always stay up to date. In addition, smoke tests with clearing partners can be helpful as soon as the connection parameters and test master data (e.g. test BICs) have been defined.
   
   
   
4. Challenge: Test data.
   Master data such as customers, accounts, and BICs can vary across different test environments and systems. Missing account settings or incorrect configurations in the booking system can negatively affect the test results and make a test object untestable.
   
   Approach: Reusing test data from previous tests saves significant preparation effort. Questions about test data should be coordinated with internal and external stakeholders early in the planning phase. Smoke testing helps minimize risks from incompatible test data. Most test software tools for CV messages support the reuse of test data, the use of previously defined master data (such as BICs and IBANs), and allow validation without involving other test partners. The simulation of incoming and outgoing payment messages is particularly helpful in the test preparation phase to check connections and data and to identify gaps in the test scope.
   
   

While following best practices does not eliminate all challenges, it significantly reduces the risk of missing time and quality targets. Implementing these measures often requires more time and resources during the preparation phase, which should be factored into project planning.

Result

Despite unavoidable challenges – such as complex dependencies, scarce resources, and test data issues – a structured testing approach helps identify risks and ensure stable, high-quality payment processes post-migration.

Banks and PSPs should seize this opportunity to optimize their CV processes in the long term – for better customer service and lower operating costs. With careful planning and support from reliable testing experts, the migration of ZV platforms can succeed without significant production disruptions.

Capco brings holistic testing experience from various projects in payment transactions. In addition to test design and implementation, we also offer support in defect management and resolution.

* Diversity is one of Capco's core values. In order to keep texts as short as possible for them, they read only the masculine form in some places, but all genders are explicitly meant.