Alford Academy Business Education and Computing1 Advanced Higher Computing Based on Heriot-Watt University Scholar Materials Implementation and Testing

Alford Academy Business Education and Computing2 Lesson Objectives Implementation, Testing, Evaluation and Maintenance

Alford Academy Business Education and Computing 3 Implementation This 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.)

Alford Academy Business Education and Computing 4 Testing Testing 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

Alford Academy Business Education and Computing 5 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

Alford Academy Business Education and Computing 6 Testing VERIFY 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

Alford Academy Business Education and Computing 7 Test Strategies VERIFY 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

Alford Academy Business Education and Computing 8 Test Strategies VERIFY 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

Alford Academy Business Education and Computing 9 Acquisition of hardware Upgrade to an existing system Purpose built site and completely new system

Alford Academy Business Education and Computing 10 Changeover Strategies How 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

Alford Academy Business Education and Computing 11 Evaluation Key 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

Alford Academy Business Education and Computing 12 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.

Alford Academy Business Education and Computing 13 Percentage Costs of Development Phases 3% 5% 7% 15% 67%

Alford Academy Business Education and Computing 14 Activities Answer Review questions 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 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