Software Engineering

MCA-303

Dr. K.P.JayantSenior Associate Professor, MCA DepartmentABES Engineering College, Ghaziabad

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Sub Topic NosSub Topic nameLecturer NoSlide Nos1Transaction flow Testing: Overview L1 32Transaction flow GraphL263Transaction flow testing techniquesL318

ref boris beizer*Definitions of Transaction,Transaction-flow, TFG

Transaction

is a unit of work seen from systems user point of view.

consists of a sequence of operations performed by a system, persons or external devices.

is created/ begin (birth) due to an external act & up on its completion (closure), it remains in the form of historical records.

Since the transaction is no longer in the system, except in the form of historical recordsU2

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ref boris beizer*Definitions of Transaction,Transaction-flow, TFGTransaction-flow

Transaction-flow represents a systems processing. Functional testing methods are applied for testing T-F.

Transaction-flow Graph

TFG represents a behavioral (functional) model of the program (system) used for functional testing by an independent system tester.

U2

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*A Simple TransactionExample: The sequence of steps in a transaction in an online information retrieval system 1. Accept inputs 2. Validate inputs (Birth of tr.) 3. Transmit acknowledgement to the user 4. Process input 5. Search file 6. Request direction from user 7. Accept Inputs 8. Validate inputs9. Process the request10. Update file11.Transmit output12.Record transaction in log & cleanup (Closure)

Users View of a transaction: Single step Systems view : Sequence of many operationsU2-B

ref boris beizer*For example, an automatic bank teller machine ATM can be used for withdrawals, deposits, bill payments, and money transfers.

Furthermore, these operations can be done for a checking account, savings account, vacation account, Current Account, and so on.

Although the sequence of operations may differ from transaction to transaction, most transactions have common operations.

Such that, the automatic teller machine begins every transaction by validating the users card and password number.

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ref boris beizer*Example of a Transaction flow (diagram)User (terminal) Terminal controller CPU

U2

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ref boris beizer*Definitions

Transaction-flow Graph : a scenario between users & computer

Transaction-flow :an internal sequence of events in processing a transaction

Uses of Transaction-flowSpecifying requirements of big, online and complicated systems.

Airline reservation systems, air-traffic control systems.Loops are less as compared to CFG. Loops are used for user input error processingU2

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ref boris beizer*Implementation of Transaction-FlowU2System Control Structure (architecture of the implementation) :

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ref boris beizer*A perspective of Transaction-FlowU2Transaction-flow testing is a block box technique.

(as we assumed nothing regarding computer, communications, environment, O.S., transaction identity or structure or state.)

TFG is a kind of DFG.TFG has tokens, & DFG has data objects with history of operations applied on them.Many techniques of CFG apply to TFG & DFG

Decision nodes of TFG have exception exits to the central recovery process. So, we ignore the effect of interrupts in a Transaction-flow.

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Transaction Flows splitting & merging decisionsref boris beizer*U2-BSplits of transactions (Births)

A decision point in TFG

BiosisMitosis

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Transaction Flows splitting & merging decisionsref boris beizer*U2Mergers of transactions

Junction

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TFG splitting, merging Transactionsref boris beizer*U2

NOTES:

Multiple meanings now for decision and junction symbols in a TFG.

Simple TFG model is not enough to represent multi-processor systems & associated coordination systems.

Petrinet model uses operations for all the above. But Petrinets are applied to H/W, N/W protocol testing but not Software.

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Transaction - Flow Testing - Stepsref boris beizer*U2-B

First, Build / Obtain Transaction Flows

Represent Explicitly

Design details the Main Tr-Flows

Create From PDL

HIPO charts & Petrinet Representations

Objective Trace the transaction

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Transaction - Flow Testing - Stepsref boris beizer*U2-B

Inspections, Reviews & Walkthroughs

Start From Preliminary Design

Conducting Walkthroughs

Discuss enough Transaction Types (98% Transactions)

User needs & Functional terms (Design independent)

Traceability to Requirements

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Transaction - Flow Testing - Stepsref boris beizer*U2-BInspections, Reviews & Walkthroughs

Design Tests for C1 + C2 coverage

Additional Coverage (> C1+C2)

Paths with loops, extreme values, domain boundariesWeird cases, long & potentially troublesome Tr.

Design Test cases for Tr. Splits & mergers

Publish Selected Test Paths early

Buyers Acceptance functional & acceptance tests

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Transaction - Flow Testing Techniquesref boris beizer*U2-BPath Selection

Covering Set (C1+C2) of Functionally Sensible Tr.

Add Difficult Paths

Review with designers & implementers

Exposure of interface problems & duplicated processing

Very few Implementation bugs may remain

Transaction-flow Path Covering Set belongs inSystem Feature Tests

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Transaction - Flow Testing Techniquesref boris beizer*U2-BSensitization

Functionally Sensible Paths Simple

Error, Exception, External Protocol Interface Paths - Difficult

Testing Tr.Flows with External Interfaces

Use patches & break points, mistune, and break the rules,

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Transaction - Flow Testing Techniquesref boris beizer*U2-BInstrumentation

Link Counters are not Useful.

Need

Trace

Queues on which Tokens resided

Entries to & Exits from Dispatcher

A Running Log

Make Instrumentation as part of System Design

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Transaction - Flow Testing Techniquesref boris beizer*U2-BTest Data bases

Design & Maintenance of a Test Data base - Effort

Mistakes

Unawareness about design of a centrally administered test DB

Test DB design by Testers

Using one DB for all tests (need 4 to 5)

Need experienced System & Test Designers

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Transaction - Flow Testing Techniquesref boris beizer*U2-BTest Execution

Use Test Execution Automation

Have to do a large # of Tests for C1+C2 coverage

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Transaction - Flow Testing - Implementationref boris beizer*U2-B

Transaction based systemsTCB

Centralized, Common Processing QueuesJust O(n) Queues for Links of O(n2)

Transaction DispatcherUses tables & Finite State Machines

Recovery & Other LogsKey events in Tr Flow

Self-Test SupportPrivileged modes in Transaction control tables

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*Q.1. Distinguish Control Flow and Transaction flow.Q.2. What is meant by transaction flow testing. Discuss its significance.