Information Technology Reference
In-Depth Information
◾
Electricity is working fine.
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Proper mixing of sugar/milk or any other additives in the tea.
1.10.1. 2
Outputs
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Is the proper quantity of tea pouring out with one press of the button?
Does the output taste like tea or something else?
◾
◾
Is the temperature of the output proper (say, 70
°
C)?
Has sugar, milk, or any other additive already been added?
◾
1.10.1. 3
Analysis
In the first example we are testing the tea vending machine from the end user
perspective. Here the end user is not concerned with the internal working of the
machine. He is concerned only with what inputs are to be given to the machine
(here pressing the push button) to get the desired output (right quality and quantity
of tea). For testing the machine, he inputs the desired and not so desired activity
and validates it by getting the quality and quantity of output. The kind of output
(valid/invalid) he gets against desired/undesired inputs provides him enough infor-
mation as to whether the machine is working fine or not.
In software testing a similar kind of activity is carried out, what is popularly
known as black box testing. Test engineers are given a software application along
with requirements and design documents and are asked to verify whether the appli-
cation is performing as per expectations mentioned in the requirements and design
documents. he test engineer does not care how the application was built. He tests
the application only by providing some valid/invalid data and getting the output.
By comparing actual output with expected output, he validates whether the appli-
cation is working fine or not.
In contrast, consider the second example of a maintenance engineer. He is
responsible for the proper functioning of the equipment. So he periodically checks
the machine by checking the internal working of the machine to ensure that all
parts are functional and that the machine as a whole is working fine.
1.10.1.4
Conclusion
In software testing parlance, this kind of testing is known as white box testing. The
test engineer knows the internal working of the application. Here the test engi-
neer has the source code or at least open interfaces of the application. He either
inserts test code or passes some data through open interfaces to get outputs from
the application. By comparing desired outputs against the actual outputs, he vali-
dates whether the application is working fine or not.
The internal defect testing is known as unit testing, and it is done by developers
themselves. Integration defect testing is known as integration testing, and again it
