Summary

4.4 Summary

Testing has as its goals the finding of defects and verifying that the software meets its requirements. The cost of finding and correcting a defect goes up dramatically with the length of time the defect is present. The basic types of testing are unit, module, integration, user or acceptance, and regression.

Unit testing is primarily a debugging activity that concentrates on the removal of coding mistakes. Module integration and testing examine the functional entities of the system. As modules pass their individual tests, they are brought into increasingly larger functional groups. Testing of the integrated modules is designed to find latent defects, as well as interface and database defects. User testing is primarily intended to demonstrate that the software complies with its approved requirements as they are perceived by the user. Regression tests are usually a subset of the user or acceptance tests. They are maintained to verify that changes made to the software do not result in failures in other parts of the system.

As the requirements for the system are prepared, the original planning for the test program also is started. During software design, the test plans are expanded into specific test cases, scenarios, and step-by-step test procedures.

Expected results are an important part of the test procedures. Unless the expected results of each test are documented, there is no way to judge whether the test has performed as intended. Analyses of the expected versus actual results of each test provide the pass or fail determination for that test.

A necessary part of the software quality practitioner's activities is the review of the test program. The software quality practitioner's additional role is to monitor the testing as it progresses. The practitioner will audit the tests against their plans and procedures and report the status of the test program to management.

Tests follow the natural progression of the SLC. The testing program begins in the requirements phase and, effectively, never ends, since regression tests continue for as long as there are changes and enhancements being made to the software system.