What is meant by defect leakage?

Defects can be defined as any discrepancies that can disrupt the functioning of a software system or application and often they are known to give nightmares and headaches to the software testers.

WHAT ARE DEFECTS?
- Defects are responsible for the production of incorrect or unexpected results and abnormal behavior of the software program.
- Defects are a consequence of the mistakes made by the software developers.

It is very difficult to set straight a buggy program. There are so many concepts that revolve around these defects. One of such concepts is defect leakage and we will be discussing it here in this article.

DEFECT LEAKAGE
- You can imagine water leaking out of a container having holes in it. We can take the defect leakage in the same context and define it.
- The defect leakage can be thought of as a phenomenon in which the defects leak out in the entire software system or application.
- It is due to the presence of the means for the escape of the defects.
- No present software testing methodology is so efficient that it can discover or dig out all the errors and bugs.
- Even after many times of rigorous testing still many bugs remain in the software system or application hidden and undiscovered.
- These defects are discovered later during the latter stages of the software development life cycle.
- Such defects are said constitute the defect leakage factor.
- Tracking the defect leakage is very time consuming process as well as effort consuming process.

APPROACHES FOR FINDING DEFECT LEAKAGE

APPROACH #1:
- The commonly followed approach for finding the defect leakage is the matrix method.
- The defect leakage can be tracked down using a standard matrix provided you can spare much of your time for following this approach.
- You will require to analyze all the defects and determine where actually the defect would have been discovered when those stages were in progress.
- Defect leakage indicates a lot about your programming efficiency and testing skills.
- If a lot of gap exists in your findings then it indicates that your testing and programming efficiency is quite low.
- In some cases it happens that you find defect leakage in the unit level which you could have discovered then and there itself and if not there at least that could have been caught at the level of the integration testing.
- The gap here that we are talking about is nothing but the difference between the actual defect logging time and ideal defect logging time.
- Defect leakages add to greater headaches than the usual defects so try avoiding them as far as possible by following a proper testing strategy and an effective test plan.
- All you need to do is to keep all your processes systematic and organized.
- If you are having a lack of time and need a fast completion of your testing work, then there is a greater probability that you may leave many bugs and errors here and there and later have problems with the defect leakages.

APPROACH #2:
- Another approach that you can follow is using a defect tracking automated system.
- This system files up a detection phase whenever a bug is logged.
- This bug is then rectified in the injection phase.
- Following this approach you can easily define the bug slippage also.
- You can also define the areas in which improvement is needed.
- This approach requires appropriate categorization of the defect injection phase.
- The categorization depends on the perception of the tester.
- A leaked defect is the one that could not be discovered during the usual testing but showed up during the production of the software.
- The documentation for the defect leakage is not produced by the quality assurance people.
- The reason why a defect was missed during the testing is often probed by the program managers.

What is a defect and what is defect management ?

Defects determine the effectiveness of the testing what we do. If there are no defects, it directly implies that we do not have our job. There are two points worth considering here, either the developer is so strong that there are no defects arising out, or the test engineer is weak. In many situations, the second is proving correct. This implies that we lack the knack.

For a test engineer, a defect is:
- any deviation from specification.
- anything that causes user dissatisfaction.
- incorrect output.
- software does not do what it intended to do.

Software is said to have bug if it features deviates from specifications.
Software is said to have defect if it has unwanted side effects.
Software is said to have error if it gives incorrect output.

Categories of Defects
All software defects can be broadly categorized into the below mentioned types:
- errors of commission : something wrong is done.
- errors of omission : something left out by accident.
- errors of clarity and ambiguity : different interpretations.
- errors of speed and capacity.

Types of defects that can be identified in different software applications are conceptual bugs, coding bugs, integration bugs, user interface bugs, functionality, communication, command structure, missing commands, performance, output, error handling errors, boundary-related errors, calculation errors, initial and later states, control flow errors, errors in handling data, race condition errors, load conditions errors, hardware errors, source and version control errors, documentation errors and testing errors.