ISQB Software Testing Section Meeting - PowerPoint Presentation

Slide1

ISQB Software Testing

Section Meeting

10 Dec 2012

Slide2

Why testing is necessary

Increasing complexity of software

Cost of software failures

"The internal [...] software exception was caused during execution of a data

conversion from 64-bit floating point to 16-bit signed integer value.

The floating point number which was converted had a value greater than what could be represented by a 16-bit signed integer. [...].“

ARIANE 5, Flight 501 Failure, Report by the Inquiry

Board

Slide3

Test and Quality

Quality

:

the degree to which a component, system or process

meets specified requirements and/or user/customer needs and expectations.Software quality: the totality of functionality and features of a software product that bear on its ability to satisfy stated or implied needs.

Slide4

ISO 9126 Software Quality

Software Quality Characteristics:

Functionality:

Specified

or expected functions (behavior): suitability, accuracy, interoperability, compliance, securityReliability: Maintenance of a certain level of performance: maturity, fault tolerance, recoverabilityUsability:Effort needed for use,

user-friendliness: understandability, learnability, operabilityEfficiency:Ratio of level of performance and used resources: time behaviour, resource behaviourMaintainability:Effort to perform defined

changes:

analysability

, changeability, stability, testability

Portability:

Ability to transfer to a different

environment

(SW, HW, etc

.):

adaptability

, installability, conformance, replaceability

Slide5

Testing principles

Testing can show the presence of

defects but not their absence

Exhaustive testing is

impossibleEarly testingDefect clusteringPesticide paradoxTesting is context dependentAbsence-of-errors fallacy

Slide6

Test Level Acceptance Testing

Test Level System Testing

Fundamental Test Process

Test Level Integration Testing

Test Level Component Testing

Planning

Analysis &

Design

Implementation & Execution

Testing Closure

Exiting criteria

Cont

ro

l

Test cycle 1...n

Slide7

Test Cases Specification

Slide8

Logical and Concrete Test Cases

Example: Logical test

case

Example

: Concrete test case

Slide9

Test Oracle

After each executed test case it has to be decided

whether there

is a failure or not:

the observed result/outcome is compared to the expected result/outcometherefore the expected result/outcome has to be determined in advance for each test casethis expected outcome has to be gathered from an appropriate source: the test oracle

Slide10

Testing in

Software Development Models

Slide11

Overview of Test Types

Slide12

Static Testing

Review

Inspection, walkthrough ...

Static Analysis

Control flow analysisData flow analysisMetricsCoding standards

Slide13

Control Flow Analysis Example

Slide14

https://security.web.cern.ch/security/recommendations/en/code_tools.shtml

CERN recommended

static analysis tools

Slide15

Test design techniques

Slide16

Equivalent Class Partitioning

Equivalent class

Set of Input values

Combinations of equivalence classes for building test cases:

All possible combinations of all valid equivalence classes

build valid

test cases. Even with a few parameters this can lead to

a high

number of test cases. For this reason, often only

frequent

combinations

are

considered

An

invalid input equivalence class should only be combined

with

valid

input equivalence

classes

Slide17

Boundary Value Analysis: Example

A function calculates z, the sum of two integer numbers x and y

For the input the following ranges are defined:

x: [0 .. 50]

y: [20 .. 100]

Parameter

Valid classes

Invalid class

x

0,50

-1,51

y

20,100

19,101

Slide18

Structures of Decision Tables

Slide19

Statement Testing

Statement coverage

Every instruction (statement) is executed at least once

Decision

coverageEvery branch is executed at least once

Slide20

Path Coverage

Path coverage

Each path is executed at least

once

Slide21

Error guessing Testing

Examples of potential errors out practice

"pathological" situations:

Empty input fields, blanks in strings

Repeated access (many times) to the same dataNo more space available, limitsNegative numbers, etc.Situations that are explicitly forbiddenSituations that "never arise"Special characters (a, s, €, etc.)Abuse and misunderstandings by the userChange from and to daylight saving time, leap year

Slide22

Exploratory Testing

Continuing learning process

Become acquainted with the product

Learn how errors in software arise and which effect those

errors haveDiscover the weaknesses of the softwareLearn how to test the softwareTest the softwareReport the problemsCreate new test cases on the basis of what you just have learned

Slide23

Testing Organization Forms

Slide24

Balance Between

Test

Cost and Failure

Cost

Slide25

Early Failure Detection as a Goal

Slide26

Testing Management Tasks

Test Management

Test Organization

Test Planning and

EstimationRisk Analysis Test Progress MonitoringFailure based metricsnumber of failures found, per release, per class, per failure status,etc.Test case based metricsnumber of blocked tests, number of successful tests, etc.Test object based metricscode-coverage, dialogue-coverage, etc.Test process based metricstest effort, on schedule milestones, etc

.Test ControlCorrective measures have to be taken:Requesting additional resourcesUpdating of the test scheduleRe-assigning prioritiesInitiation of additional test cyclesConfiguration

Management

Incident

Management

Norms and Standards

Slide27

Thanks for attending!