How do you deal with the integration testing of legacy systems that have limited documentation and support?

2 Choose the right integration testing approach

There are different approaches to integration testing, such as top-down, bottom-up, sandwich, and big bang. Each approach has its own advantages and disadvantages, depending on the system complexity, availability, and testability. For legacy systems, you may have to consider factors such as the stability, coverage, and risk of the components, as well as the feasibility and cost of creating test drivers and stubs. You may also have to combine different approaches or use incremental or iterative integration testing to deal with changing requirements or dependencies.

3 Use the right integration testing tools

Integration testing tools can help you automate, manage, and report your integration testing activities. However, legacy systems may not be compatible or integrated with modern tools, or may require custom or proprietary tools. You may have to evaluate the available tools and their features, such as data generation, test execution, test orchestration, test verification, and test reporting. You may also have to adapt or modify the tools to suit your system requirements and constraints, or use a combination of tools to achieve your integration testing goals.

4 Communicate and collaborate with stakeholders

Integration testing involves multiple stakeholders, such as developers, testers, business analysts, project managers, and end users. You need to communicate and collaborate with them effectively to ensure that your integration testing is aligned with the system objectives, expectations, and standards. However, legacy systems may have limited or outdated documentation and support, or may have different owners or vendors. You may have to establish clear roles and responsibilities, communication channels, feedback mechanisms, and escalation procedures for your integration testing. You may also have to involve the stakeholders in the planning, design, execution, and review of your integration testing.

5 Manage the integration testing risks and challenges

Integration testing legacy systems may pose various risks and challenges, such as technical debt, code quality, performance, security, compatibility, maintainability, and scalability. You need to identify, assess, and mitigate these risks and challenges proactively and systematically. You may have to use techniques such as risk-based testing, code reviews, refactoring, performance testing, security testing, compatibility testing, and regression testing to ensure that your integration testing is comprehensive and robust. You may also have to monitor and measure the integration testing results and outcomes, and report and resolve any issues or defects promptly and effectively.

6 Learn from the integration testing experience

Integration testing legacy systems can be a valuable learning opportunity for you and your team. You can learn from the integration testing process, results, and feedback, and use them to improve your integration testing skills, practices, and tools. You can also use the integration testing experience to identify and implement best practices, standards, and guidelines for your future integration testing projects. You can also share your integration testing lessons learned and recommendations with other stakeholders and teams, and contribute to the continuous improvement of the system quality and reliability.

7 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?