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8.1 Development testing 211

Debugging

Debugging is the process of fixing errors and problems that have been discovered by testing. Using information
from the program tests, debuggers use their knowledge of the programming language and the intended
outcome of the test to locate and repair the program error. This process is often supported by interactive
debugging tools that provide extra information about program execution.

http://www.SoftwareEngineering-9.com/Web/Testing/Debugging.html

programmer has an associated tester who develops tests and assists with the testing
process. For critical systems, a more formal process may be used, with a separate
testing group within the development team. They are responsible for developing tests
and maintaining detailed records of test results.
During development, testing may be carried out at three levels of granularity:

1. Unit testing, where individual program units or object classes are tested. Unit
testing should focus on testing the functionality of objects or methods.
2. Component testing, where several individual units are integrated to create com-
posite components. Component testing should focus on testing component
interfaces.

3. System testing, where some or all of the components in a system are integrated
and the system is tested as a whole. System testing should focus on testing com-
ponent interactions.

Development testing is primarily a defect testing process, where the aim of testing
is to discover bugs in the software. It is therefore usually interleaved with debugging—
the process of locating problems with the code and changing the program to fix these
problems.

8.1.1 Unit testing
Unit testing is the process of testing program components, such as methods or object
classes. Individual functions or methods are the simplest type of component. Your
tests should be calls to these routines with different input parameters. You can use
the approaches to test case design discussed in Section 8.1.2, to design the function
or method tests.
When you are testing object classes, you should design your tests to provide cov-
erage of all of the features of the object. This means that you should:
• test all operations associated with the object;

• set and check the value of all attributes associated with the object;
• put the object into all possible states. This means that you should simulate all
events that cause a state change.