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DO NOT DISTRIBUTE – HIGHLY CONFIDENTIAL
Agenda:
Test Design Techniques

Test Design Techniques:
What is a testing technique?
• A procedure for selecting or designing tests.
• Based on a structural or functional model of the software.
• Successful at finding faults.
• Best practice.
• A way of deriving good test cases.
• A way of objectively measuring a test effort.
Note: Testing should be rigorous, thorough and
systematic.
2www.talentsprint.com

Advantages of Techniques:
• Different People:
– Higher probability to find similar faults.
– Gain some independence of thought
• Effective Testing:
– Finds more faults
– Focus attention on specific types of fault
– Know you're testing the right thing

• Efficient Testing:
– Find more faults with less effort
– Avoid duplication
– Systematic techniques are measurable
Note: Using techniques makes testing much more effective.

6
Introduction to Testing Techniques
Testing
Techniques
Scripted Testing
Experience
Based Testing
Static
Testing
Dynamic
Testing
Tool-Based
Testing
People-Based
Testing
Black Box
Testing
White Box
Testing
Error-Guessing
Technique
Error-Guessing
Testing
Technique

7
Based on behavior /
functionality of software
Based on structure of
software
Introduction to Testing Techniques
Examination of
documentation, source code
listings, etc.
Static
(Non-execution)
Behavioral
(Black Box)
Structural
(White Box)
Types of Systematic Techniques
Dynamic Testing

Scripted Testing:
• People Based Testing
• Tool Based Testing
Reviews
Walkthroughs
Desk-checking
Static AnalysisInspection
etc.
Static

When is scripted testing used?
• Repeatability:
– When the tests are detailed enough so that some one other than the
author to execute it in an identical way.
• Objectivity:
– Test creation does not depend on the extraordinary skill of the
person creating the test but is based on well understood test design
principles.
• Auditability: Traceability from requirements, design, and code to
the test cases and back again.

10
IEEE 829 Test Documents?
Scripted Testing
Test Plan
Test Design
Specification
Test Log
Test
Incident
Report
Test
Execution
Test Item
Transmittal
Report
Test Case
Specification
Test Procedure
Specification
Test
Summary
Report

Dynamic Testing:
– White Box Test Design Techniques
– Black Box Test Design Techniques

White Box Test Design Techniques:
• The main objective of white box testing is to ensure 100%
code coverage.
Code coverage:
• The percentage of code tested during white box testing is called code
coverage.
• The source code behind a unit may contain a set of statements, a set of
conditions and a set of branches. If all these are tested, then we say
100% code coverage is achieved.

Why White Box Test Design Techniques:
• As testing everything at code level may be impossible.
• To avoid this, at the same to ensure 100% code coverage
the following techniques are introduced in white box
testing.

• Statement Coverage
• Branch/Condition/ Decision Coverage
• Path Coverage
• Cyclomatic Complexity

Statement Coverage:
• The percentage of statements tested during white box
testing is called statement coverage.
• Statement coverage=
(Number of statements tested/total number of statements) x 100

Branch/ Decision/ Condition Coverage:
• The percentage of branches tested during white box
testing is called branch coverage.
• Branch coverage=
(Number of branches tested/total number of branches) x 100

Path Coverage:
• The percentage of paths tested during white box testing is
called path coverage.
• Path coverage=
(Number of paths tested/total number of paths) x 100

Cyclomatic Complexity:
• Cyclomatic complexity is a source code complexity
measurement that is being correlated to a number of
coding errors.
• It is calculated by developing a Control Flow Graph of the
code that measures the number of linearly-independent
paths through a program module.

Cyclomatic complexity =E - N + P
where,
E = number of edges in the flow graph.(Lines)
N = number of nodes in the flow graph.(Shapes)
P = number of nodes that have exit points

• Cyclomatic Complexity C = Number of Decision Points
(i.e. the Decision Boxes in Flow diagram) + 1

Points to Remember:
• 100% LCSAJ will ensure 100% branch coverage.
• 100% branch coverage will ensure 100% statement
coverage.
• 100% path coverage will ensure 100% statement
coverage.
• 100% path coverage will ensure 100% branch coverage.
• Best Technique: Path Coverage.

Case Study :
• Consider a code and how many minimum number of tests are required
to cover 100% Statement & Branch & Path coverage & what is
Cyclomatic Complexity?
Read P
Read Q
IF P+Q >100 then
Print “Large”
End IF
IF P>50 then
Print “ P Bigger”
End IF

Assignment-1
Read A
If A>0 then
If A>21 then
Print “Key”
End IF
End If

Assignment-2
Read A
Read B
If A>0 then
if B=0 then
Print “No Values”
else
Print B
if A>21 then
Print A
End If
End IF
End If

Assignment-3
Read A
Read B
If A<0 then
Print “A Negative”
else
Print “A Positive”
End IF
If B<0 then
Print “B Negative”
else
Print “B Positive”
End If

Assignment-4
Read A
Read B
If A<0 then
End IF
If B<0 then
Print “B Negative”
End If

Assignment-5
Read A
If A<0 then
End IF
If A>0 then
Print “A Positive”
End If

Review Questions:
White Box Testing Techniques:
• The Structure-Based or White Box Testing Techniques, as described
in BS 7925-2 standards, are :
– Statement Testing
– Branch / Decision Testing
– Data Flow Testing
– Branch Condition Testing
– Branch Condition Combination Testing
– Modified Condition Decision Testing
– LCSAJ (Linear Code Sequence and Jump) Testing
Note: All these techniques can also be used as Measurement Techniques.

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