Testing Life Cycle – Part 2

The first part of the testing life cycle covered component and integration tests as an essential part of the testing process. As these parts mainly focus on tests on development level, system and acceptance tests follow an use case or requirement approach.

System test

Goal of the system test is to ensure, that the integrated system comes up with the specific requirements. The test steps upfront test technical specifications from a software developers perspective. The system test deals with the users perspective and validates if all requirements are implemented fully and appropriate. Besides, some characteristics can only be tested when all components are integrated and work together. The tests are based on all documents describing the software on system level like requirements specifications, technical manuals or business related concepts.

System tests are used for:

• validating if and how good the system fulfills the requirements.
• identifying errors based on wrong or incomplete implemented requirements.
• identifying undocumented or forgotten requirements.

Ideally, a system test is performed on an environment that fits the later production system as close as possible. Instead of stubs and mocks, the system should use all interfaces, hardware components and data which will be involved during live operation. Problems may occur, if the system requirements are ambiguous and not fully documented or some necessary decisions are not made yet.

Acceptance test

All test activities described until now are in charge of the software developer or service provider. Before the product is put into production, a final acceptance test is performed by the client. The scope of the acceptance test is determined based on risk analysis: how critical is the usage of the new software for the clients own business.

Typical aspects of acceptance tests are:

• Test for contractual acceptance: Based on clearly defined contractual acceptance criteria, the client decides, if the system fits his needs. Test cases cover these criteria. It’s important that these test cases are defined by the client himself in order to prevent misunderstanding.
• Test for user acceptance: This test is recommended if the system may be used by different user groups. Each user group has its own expectations. If one group declines the new system, this may result in a failure of the project. The tests are usually designed by the client.
• Acceptance by system operator: This test ensures, that the new system fits in the existing IT environment. Covered are backup routines, user administration or aspects of data security.
• Field test: The client provides the new system in a beta test to a selected group of potential users. These users interact with the system in an realistic environment and perform common tasks. If the test proofs the required stability, the system may be put into production.

Use cases for an acceptance test are based on the same criteria and documents as a system test, enriched with the expertise of the client.