What’s the difference between failure, defect and error?

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What’s the difference between failure, defect and error?

Asked 7 years, 7 months ago

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In software development often problems occur in the application already ready, some terms used to classify them are: glitch, defect and error.

What is the difference between one term and the other?
These terms are defined in some ISO or similar?
Is there any other relevant term denoting this situation of "unexpected result/problem"?

2

Fault is of others, defect has come so and error I do not commit :D

– Maniero

2017/05/15 at 16:40
@moustache defect or hidden addiction? haha

– rray

2017/05/15 at 16:41
If ISO is non-compliance :)

– Maniero

2017/05/15 at 16:45
The concepts of error, Failure, fault are many used in software testing, but never thought of those "words" out of that context.

– Randrade

2017/05/15 at 16:49
@Randrade this, you think you missed the test tag?

– rray

2017/05/15 at 16:50
@rray I really was in doubt if it possesses another meaning without being in tests. But, if the doubt is about that same area, I think it would fit yes.

– Randrade

2017/05/15 at 16:51
1

@Guilhermenascimento "defect" here in Portugal is equal to Brazil. Indicates "inaccuracy, irregularity, failure, inaccuracy, imperfection, inaccuracy, error, deficiency, deformation". " By default" is used as equivalent to "default".

– ramaral

2017/05/15 at 16:56
@ramaral understood, thank you :)

– Guilherme Nascimento

2017/05/15 at 16:58

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by Taisbevalle • **8,942** points · Answer 1 · 2017-05-16T14:48:14+00:00

What is the difference between one term and the other?

Glitch: It is an unexpected software behavior. A failure may have been caused by several errors, but some errors may never cause a failure. Practical example: There was a return of an unexpected value, such as null, This is a mistake, and because of that null caused a system failure.
Defect: It is an inconsistency in software, something that has been implemented incorrectly. It occurs in a line of code, such as a wrong instruction or an incorrect command. The defect is the cause of an error, but if a line of code containing the defect never runs, the defect will not cause an error.
Error: Human error producing incorrect result. The error shows the defect, that is, when there is a difference between the obtained value and the expected value constitutes an error.

In short, if by mistake you make a if wrong, causes a defect, which when activated will produce an error. If this error is propagated until the software output will constitute a failure.

These terms are defined in some ISO or similar?

Yes. ISO/IEC/IEEE 29119 Software Testing, but specifically at IEEE 829 Test Documentation.

Is there any other relevant term denoting this situation of "result not expected/problem"?

Yes. Incident or anomaly that is the same as defect. In practice everything wrong that happens we call "bug".

References:

by Fillipe • **555** points · Answer 2 · 2017-05-16T15:00:07+00:00

Glitch: Imagine the second line of code:

if (x < 10):{ //WHOLE }

The programmer forgot to put the "=", in case the correct code would be:

if(x <= 10){ //WHOLE }

i.e., failure, is any external interference that compromises the flow of software, be it human interference (programmer forgot something), lightning, a bomb...

The Error happens when this failure is noticed, that is, when in a test, the failure is activated! Let’s say in tests, x = 10, and it is expected to enter within the condition.

The defect happens when the error behavior is noticed, then it is faulty!

Is a cycle: