alford academy business education and computing1 advanced higher computing based on heriot-watt...
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Alford Academy Business Education and Computing 1
Advanced Higher Computing
Based on Heriot-Watt University Scholar Materials
Implementation and Testing
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Lesson Objectives
Implementation, Testing, Evaluation and Maintenance
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ImplementationThis is the stage at which the software is coded, the user interface designed, hardware is set up and any legacy files are converted to the formats needed by the new system
Coding
Need to select a programming language in which to implement the code. The language needs to suit the problem:
Procedural (Pascal, Comal, etc)
Declarative (Prolog)
Event Driven (VBasic, etc.)
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TestingTesting must be systematic – this means that it is carried out in a rigorous and structured manner.
Large-scale system testing
ATM
VERIFY CARD ENTRY
HANDLE MENU SELECTION
HANDLE CASH AND RECEIPT OUTPUTS
Modular approach breaks the large problem into smaller subsystems
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Testing
SUBSYSTEMS are coded and MODULES are tested independently
VERIFY CARD ENTRY
READ USER ACCOUNT DATA
CONTACT MAINFRAME
ACCEPT OR REJECT CARD MESSAGE
ACCESS MAGNETIC
STRIPE DATA
GET PIN NUMBER
VERIFY ACCOUNT DETAILS
VERIFY CARD ENTRY SUBSYSTEM
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TestingVERIFY CARD
ENTRY
READ USER ACCOUNT DATA
CONTACT MAINFRAME
ACCEPT OR REJECT CARD MESSAGE
SUB-SYSTEMS are coded and MODULES are tested independently
ACCESS MAGNETIC
STRIPE DATA
GET PIN NUMBER
VERIFY ACCOUNT DETAILS
VERIFY CARD ENTRY SUB-SYSTEM
SUB-SYSTEMS are then integrated and the whole system is tested
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Test StrategiesVERIFY CARD
ENTRY
READ USER ACCOUNT DATA
CONTACT MAINFRAME
ACCEPT OR REJECT CARD MESSAGE
ACCESS MAGNETIC
STRIPE DATA
GET PIN NUMBER
VERIFY ACCOUNT DETAILS
Without knowing the detail of the module code, test cases are built to test the inputs and outputs of the module. For the highlighted module, what test cases would you choose?
Black Box Testing
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Test StrategiesVERIFY CARD
ENTRY
READ USER ACCOUNT DATA
CONTACT MAINFRAME
ACCEPT OR REJECT CARD MESSAGE
ACCESS MAGNETIC
STRIPE DATA
The structure of the code is examined and test cases are used to check that the logic of the code is correct. What test cases would you use here?
White Box Testing
GET PIN NUMBER
validPin = false
Do
pin = inputbox(“Enter pin number”)
if Len$(pin) < 4 then
msgbox(“invalid pin”)
elseif not Int(pin) then
msgbox(“invalid pin”)
else
validPin = true
Loop until validPin = true
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Acquisition of hardwareUpgrade to an existing system
Purpose built site and completely new system
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Changeover StrategiesHow will the new system be brought in to replace the old system?
Parallel conversion:- run the old in parallel with the new for a period of time until you are satisfied that the new system is reliable and error-free.
Phased conversion:- Same as parallel only on a smaller scale. Run the new system in phases and as each is tested and is proven to be robust, introduce a new phase.
Pilot conversion:- Restrict to a section of the old system – if the new section works then changeover.
Direct conversion:- Immediately convert to the new system – also known as the ‘big bang’
Combined conversion:- Involves a mixture – some parts of the old system are immediately changed over while others are phased in or piloted
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EvaluationKey question – is the new system FIT FOR PURPOSE ie does it meet the original specification of the ORD and allow the client to operate successfully
Methods:- questionnaires, interviews, observations, bring in consultants who specialise in evaluations, data logging.
Evaluation Criteria
• the time it takes to install a piece of equipment
• the number of errors an operator makes while doing a specific task
• the time it takes an operator to complete a task
• the number of times a computer crashes or hangs
• the number of phine-calls made to a help-line
• the number of times a user consults a manual
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Maintenance
This comes into effect once a system has passed its ACCEPTANCE TEST
Perfective – Adaptive - Corrective
Preventive Maintenance:- deals with updating the system documentation and changing the structure of the software to ease future maintainability.
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Percentage Costs of Development Phases
3%
3%
5%
7%
15%
67%
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Activities
Answer Review questions 14-18 on pages 23 and 24 of the Scholar booklet
Do the End of Topic Test on pages 24 and 25 of the Scholar booklet
Homework – Read pages 19-23 of Scholar booklet and begin to prepare your own summary notes – you may wish to copy some of the text and diagrams from the Scholar website