Increasing Class-Component Testability

Testability has many effects on software. In general, increasing testability makes detecting faults easier. However, increasing testability of third party software components is difficult because the source is usually not available. This paper introduces a method to increase component testability. This method helps a user test when the component is reused during integration. First, we analyze a component to gather definition and use information about method and class variables. Then, this information is used to increase component testability to support component testing. Increased testability helps to detect errors, and helps testers observe state variables and generate inputs for testing. This paper uses an example to report the effort (in terms of test cases) and effectiveness (in terms of killed mutants).