BLACK BOX TECHNIQUES

It is a good all-round specification-based black-box technique. It can be applied at any level of testing and is often a good technique.

It is better to use the technique informally than not at all, it is much better to use the technique in a formal way to attain the full benefits that it can deliver.

The idea behind the technique is to divide a set of test conditions into groups or sets that can be considered the same.

The equivalence partitioning technique then describes that we need to test only one condition from each partition.

For example, a saving account in a bank earns a different rate of interest depending on the balance in the account.

When we say a partition is ‘invalid ‘,it doesn’t mean that it represents a value that cannot be entered by user. It just means that it is not one of the expected inputs for this particular field.

The software should correctly handle values from the invalid partition, by replying with an error message ‘Balance must me at least $0.00.

Equivalence Class Partitioning

Definition: A boundary value is any input or output value on the edge of an equivalence partition. It’s a black box test design technique where test cases are designed by using boundary values; BVA is used in range checking.

Objective :Boundary value analysis leads to a selection of test cases that exercise bounding values.

Guidelines :If an input condition specifies a range bounded by values a and b, test cases should be designed with value a and b, just above and below a and b.

Boundary Value Analysis(BVA)

Example

CONDITIONS(Candidate)

VALID BOUNDARY & EDGES

TAG(applicable

)

INVALIDBOUNDARY

TAG(not-

applicable)

Relevant Experience

Number should be 0

to 99

0 ,1 – 98,99

A1

-0.01 & 99.01

B1

Year of Passing

1975 to 2008

1975,1976 –

2007,2008A2

1974 – 2009

B2

A black-box test design technique where the cases are

designed to execute the combinations of inputs(causes)

with their associated outputs(effects) in a table format

where each column represents a unique combination.

The input conditions and actions are often stated either

true/false(Boolean).

It overcomes the defect of EP/BVP which becomes

complicated when different combinations of inputs has

to be given.

Decision table

State Transition diagram represents one specific entity

at a time

It describes the states of an entity

It also describes the events that affect the entity, the

transitions of the entity from one state to another, and

actions that are initiated by the entity.

STATE TRANSITION TESTING

oWhat is a Scenario?

oWho is an Actor?

oWhat is a Use case?

USE CASE TESTING

Use Case Model

Maintains Database

Withdraw cash

Deposit cash

Administrator

customer

ActorsUse Cases

Actor initiating

Use cases

Main Success Scenario

Step Action

1 A:Actor Clicks on the Login page of the site.

2 S:System prompts the actor to supply Username and Password.

3 A: Actor supplies the Username and Password Details.

4 S:System Gets the User ID and decrypts the Password. System compares User ID & the Password provided by the user with the stored User ID & Password. If the comparison is successful actor is directed to the Next Page.

5 Use Case ends

Use Case Descriptions

Basic Fl

ow

Extensions Step Action

3a S:If invalid Username and Password is given then a message should be displayed “to reenter Username and Password”

3b A:If User forgets the Password then Actor should invoke forgot password S:System prompts for email addressA:Actor provides the email addressS:System Validates the user provided email address with stored email Address.If System validation is successful ,reset password is emailed to actor.

4a S:If validation is not successful then go to 3a

Altern

ate Fl

ow

Thank You