Regression tests answer the question ???
Has any feature broken since (the last build/moving
the build onto a different OS/language etc
.
????
This takes longer.
The Overall Test Life-Cycle
87
If the software is highly-critical it may be preferable to have the system modeled by a part of the test
team using a formal methods tool in order both to check the feasibility and correctness of the assumptions
and to generate tests automatically. See section 4.4 for a discussion of such tools.
Preparing the system test specifications acts as a major control of the testability of the software
requirements specification itself. Each system test should be clearly related to the requirement from which
it was derived. Three major problems may appear:
1.
Requirements are incomplete.
Every menu and window has perhaps been specified within the
definition of each feature. But not every interaction perhaps. Alternatively, users (and everyone
else) may expect some feature to be present but because they were quite obviously essential they
were forgotten. Requirements may simply emerge as a result of users (in this case, testers) interacting
with the system (
?????¦Well, of course you need to be able to save files??¦???
).
2.
Requirements confusion.
The specification was ambiguous. The testers read it one way and the
developers another: see the little story in
Terms Used
in the Glossary.
3. A specification may be written in such a way as to render it
untestable.
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