Arunkumar Khannur's Software Testing Knowledge Center

5.2 Errors

Errors are mistakes in product or work product in software development and are the basic quality measure. Error is defined as a deviation of the system or its components from expected result or behavior. Error, also, is defined as a variance from a desired product attribute. Errors are not important to the user as long as they do not affect operations, or cause inconvenience, or cost time or money, or cause loss of confidence in the program’s results.

Error is a product anomaly. Anomaly may occur in the form of any condition causing deviation from expectations based on requirements specifications, design documents, user documents, standards, etc., or from someone's perceptions or experiences or because of ineffective translation from one phase to another phase during software development.. When non-conformance with requirements happens, software fails to meet customer/user expectations. On the other hand during software development, during translation of a work product of one phase to work product of another phase non-conformance may occur because of because of lack of traceability; or because of because of non-conformance with standards, or exit criteria; or failure to meet performance because of bad architecture.

Some errors can be detected easily during development. But some errors will be found late in the development process. These are low probability errors which are hard to detect and occur on very sparse set of inputs.

Errors can occur as a result of sporadic events or chronic events. Errors caused by sporadic events occur infrequently and when they occur they demand immediate attention to address them. It is difficult and very time consuming to address such errors from sporadic events. Usually cost in terms of expenditure is projected in such errors. Field errors reported from the system that is operational is an example of error caused by sporadic events.

Errors also can occur from chronic events. Such errors occur frequently and part of routine exercise during review and testing that are part of software development. Errors of this type take less time to fix and cost is not tracked. Errors reported as test findings and review findings are examples of errors of chronic events.
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Arunkumar Khannur, Software Testing - Techniques and Applications, Published by Pearson Publications, 2011 (ISBN:978-81-317-5836-6; Pages:341 + xxii)
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