TECNICAS NO FUNCIONALES

White Box test design and measurement techniques

•techniques defined

–Statement testing

–Branch / Decision testing

–Data flow testing

–Branch condition testing

–Branch condition combination testing

–Modified condition decision testing

–LCSAJ testing

•also defines how to specify other techniques

Also a measurement

technique?

Using structural coverage

Spec

Enough

tests?

What's

covered

More tests

Stronger structural techniques (different structural elements)

Coverage OK?

Increasing coverage

The test coverage trap

Function exercised,

insufficient structure

Functional 

testedness

Bettertesting

Functional

testedness

Structure exercised,

insufficient function

Statement 

Branch 

Condition

                                                                        Combination 

100% coverage doesnot mean 100% tested!

Coverage indicates thoroughnessbut is not equal to thoroughness

Statement coverage

Statement coverage

is normally measured

by a software tool.

•percentage of executable statements exercised by a test suite

number of statements exercised

    total number of statements

•example:

–program has 100 statements

–tests exercise 87 statements

–statement coverage = 87%

Typical ad hoc testing achieves 60 - 75%

Example of statement coverage

As all 5 statements are ‘covered’ by

this test case, we have achieved

100% statement coverage

Statement

numbers

Decision coverage(Branch coverage)

Decision coverage

is normally measured

by a software tool.

•percentage of decision outcomesexercised by a test suite

number of decisions outcomes exercised

    total number of decision outcomes

•example:

–program has 120 decision outcomes

–tests exercise 60 decision outcomes

–decision coverage = 50%

Typical ad hoc testing achieves 40 - 60%

Paths through code

Paths through code with loops

for as many times as it

is possible to go round

the loop (this can be

unlimited, i.e. infinite)

Partial ordering of structural coverage

Where:

All Paths = Path Coverage

L= LCSAJ

B = Branch/Decision Coverage

S = Statement Coverage

BCC = Branch Condition Combination Coverage

MCDC = Modified Condition Decision Coverage

BC = Branch Condition Coverage

How many test cases required?

•can calculate the minimum number

–to achieve statement coverage and branch coverage

•in a control flow diagram

–for statement coverage

•need enough test cases to ‘cover’ all the ‘boxes’

–for branch / decision coverage

•need enough test cases to ‘cover’ all the ‘lines’

Tips

Cyclomatic

complexity

Minimum no. of

tests to achieve 100%

Branch Coverage/

Decision Coverage

Minimum no. of

tests to achieve 100%

Statement Coverage

Statements only, no decisions

Read A

Read B

Print “Sum is”

Print A + B

Print “Product is”

Print A*B

ELSE’s = 0 + 1 = 1 =  SC

Indentations (Tabs)  = 1 = BC

sequence - treat as a single statement

–cyclomatic complexity: __1___

–minimum tests to achieve:

•statement coverage: ___1___

•branch coverage: ___1__

One decision, no ELSE

–cyclomatic complexity: _____

–minimum tests to achieve:

•statement coverage: ______

•branch coverage: _____

Otherwise

(ELSE

–cyclomatic complexity: _____

–minimum tests to achieve:

•statement coverage: ______

•branch coverage: _____

One decision with ELSE

–cyclomatic complexity: _____

–minimum tests to achieve:

•statement coverage: ______

•branch coverage: _____

Self-draw 1

Draw the

diagram

in your

notes

–cyclomatic complexity: _____

–minimum tests to achieve:

•statement coverage: ______

•branch coverage: _____