Chapter 8: Testing

What is an equivalence partition? Give an example.

A class of inputs or outputs where it is reasonable to expect that the system will behave the same way for all members of the class. For example, all strings with less than 256 characters.

What is stress testing and why is it useful?

Increasing the load on a system beyond its design limits to check how the system performs in this situation. This tests the failure behavior of the system and may reveal defects that are only apparent when the system has to handle a heavy load.

What is scenario testing?

Scenario testing is an approach to release testing where you write a story describing how a system may be used and design tests based on the sequence of events in the scenario.

Briefly summarize the test-driven development process

a. Identify increment of functionality required b. Design tests for this functionality and implement as executable programs. c. Run test along with other implemented tests. The test will fail. d. Implement the functionality and re-run the test. Iterate until the test works. e. Move on to implement the next chunk of functionality

What are the three types of user testing?

~Alpha testing, where users work with the development team to test the software as it is being developed. ~Beta testing where the software is released to selected users for testing before the formal system release ~Acceptance testing, where customers test a system to check that it is ready for deployment.

What guidelines does Whittaker suggest for defect testing?

~Chose inputs that force all error messages to be generated, ~Design inputs that might cause buffers to overflow, ~Repeat the same input numerous times, ~Force invalid outputs to be generated ~Force computation results to be too large or too small.

Briefly describe the three principal stages of testing for a commercial software system.

~Development testing, where the system is tested to discover bugs and defects ~Release testing where the system is tested to check that it meets its requirements ~User testing where the system is tested in the user's environment.

What are the advantages of inspections over testing?

~Inspections can discover many errors. In testing, one error may mask another. ~Incomplete versions of a system can be inspected. ~Inspections can consider broader quality attributes as well as program defects.

What are the three important classes of interface errors?

~Interface misuse, ~Interface misunderstanding, ~Timing errors.

What should be the principal concerns of system testing?

~Testing the interactions between the components and objects that make up the system. ~Testing reusable components and systems to check that they work as expected when integrated into the system.

What tests should be included in object class testing?

~Tests for all operations in isolation, ~Tests that set and access all object attributes, ~Tests that force the object into all possible states.

What is the distinction between validation and verification?

~Validation: Are we building the right product? ~Verification: Are we building the product right?