Exercise in Test Cases
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Category: Software Testing @ OneStopTesting
Forum Name: Beginners @ OneStopTesting
Forum Discription: New to the Club...!!! Don't Worry, We are here for you...!!! Learn the very basics of Software Testing and other pertinent Informations.
URL: http://forum.onestoptesting.com/forum_posts.asp?TID=5297
Printed Date: 19Jul2025 at 3:59am
Topic: Exercise in Test Cases
Posted By: nachiketh
Subject: Exercise in Test Cases
Date Posted: 23Mar2008 at 3:05am
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can someone please send me exercises for writing testcases?
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Replies:
Posted By: varunsen
Date Posted: 07Jun2008 at 12:31am
Hey friend,
i m giving way to write effective test classes..
sting cannot ensure complete eradication of errors. Various types of Testing have their own limitations. Consider
Exhaustive black box and white box testing, which are practically not
"Exhaustive" to the verbose as they are required to be, owing to the
resource factors. While testing a Software Product, one of the most
important things is the design of effective test cases. A Tester tries
to ensure quality output in Black box testing by identifying which
subset of all the possible test cases has highest probability of
detecting most of the errors?
A
test case is there in place to describe how you intend to empirically
verify that the software being developed, confirms to its
specifications. In other words, the author needs to cover all the
possibilities that it can correctly carry out its intended functions.
An independent tester to carry the tests properly should write the test
case with enough clarity and detail.
Each
Test case would ideally have the actual input data to be provided and
the expected output. The author of Test cases should mention any manual
calculations necessary to determine the expected outputs. Say a Program
converts Fahrenheit to Celsius, having the conversion formulae in Test
case makes it easier for the Tester to verify the result in Black box
testing. Test Data can be tabulated as in a column of input items and
the corresponding column of expected outputs.
Though
when we talk about random input testing, there is a little chance of
being near or exactly around the probability of detecting most of the
defects. Hence, the Author is required to give more attention to the
certain details.
It
requires thought process that allows tester to select a set of test
data more intelligently. He will try to cover a large set of
Probabilities of occurrence of error, in other words generating as many
Scenarios for the test cases. Besides, he looks in other possible
errors to ensure that the document covers the presence or absence of
errors in the product.
The approach of an author/tester towards Black box testing has been focused here.
Black box Testing:
Functional
testing addresses the overall behavior of the program by testing
transaction flows, input validation and functional completeness. Which
is known as Black box Testing. There are four important techniques,
which are significantly important to derive minimum test cases and
input data for the same.
Equivalence partitioning:
An
equivalence class data is a subset of a larger class. This data is used
for technically equivalence partitioning rather than undertaking
exhaustive testing of each value in the larger set of data. For
example, a payroll program, which edits professional tax deduction
limits within Rs. 100 to Rs. 400, would have three equivalence
partitions.
Less than Rs.100/- (Invalid Class)
Between Rs.100 to Rs.400/- (Valid Class)
Greater than Rs.400/- (Invalid Class)
If
one test case from one equivalence class results in an error, all other
test cases in the equivalence class would be expected to result the
same error. Here, tester needs to write very few test cases, which is
going to save our precious time and resources.
Boundary Value Analysis:
Experiences
show that the test cases, which explore boundary conditions, have a
higher payoff than test cases that do not. Boundary conditions are the
situations directly on, above and beneath the edges of input and output
equivalence classes.
This
technique consists of generating test cases and relevant set of data,
that should focus on the input and output boundaries of given function.
In the above example of professional tax limits, boundary value
analysis would derive the test cases for:
Low boundary plus or minus one (Rs.99/- and Rs.101/-)
On the boundary (Rs.100/- and Rs.400/-)
Upper boundary plus or minus one (Rs.399 and Rs.401/-)
Error Guessing:
This
is based on the theory that test cases can be developed, based upon
intuition and experience of the test engineer. Some people tend to
adapt very naturally with program testing. We can say these people have
a knack for ’Smelling out’ errors without incorporating any particular
methodology.
This “Error Guessing” quality of a tester enables him
to put in practice, more efficient and result oriented testing than a
test case should be able to guide a Tester.
It is difficult to give
procedure for the error guessing technique since it is largely
intuitive and ad hoc process. For example Where on of the input is the
date test engineer may try February 29,2000 or 9/9/99.
Orthogonal Array:
Particularly
this technique is useful in finding errors associated with region
faults. An error category associated with faulty logic within software
component.
For example
there are three parameters (A, B & C) each of which has one of the
three possible values. Which may require 3X3X3=27 Test cases. But
because of the way program works it is probably it is more likely that
the fault will depend on the values of only two parameters. In that
case fault may occur for each of these 3 test cases.
1. A=1,B=1,C=1
2. A=1,B=1,C=2,
3. A=1,B=1,C=3
Since
the value of the 'C' seems to be irreverent to the occurrence of this
particular fault, any one of the three test cases will suffice.
Depending upon the above assumption, test engineer may derive only nine
test cases. Which will show all possible pairs within all three
variables. The array is orthogonal because of each pair of parameters
all combination of their values occurs once.
That
is all possible pair wise combination between parameters A
& B, B & C, C & A are shown since we are
thinking in terms of pairs we say this array has strength of 2, It does
not have strength of 3,
because not all thee way combination occurs
A=1, B=2, C=3 for example, don’t appear but it covers the pair wise
possibilities which is what we are concern about.
White box Testing:
Structural
testing includes path testing, code coverage testing and analysis;
logic testing nested loop testing and many similar techniques. Which is
known as white box testing.
1. Statement Coverage: Execute all the statements at least once.
2. Decision Coverage: Execute each decision directions at least once.
3. Condition Coverage: Execute each condition with all possible outcomes at least once.
4.
Decision / Condition Coverage: Execute all possible combinations of
condition outcomes in each decision. Treat all iterations as two way
conditions exercising the loop zero times and Once.
5. Multiple Condition Coverage: Invokes each point of entry at least once.
A
Tester would choose a combination from above technique that is
appropriate for the application and available time frame. A very
detailed focus on all these aspects would lead to too much of vague
information at times.
Thanks
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Posted By: vinothini_msc
Date Posted: 07Jun2008 at 5:19am
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1.Create a test case for calculator[windows application]
2.Create a test case for purchasing computer online [webapplication]
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