Design Development And Testing

• The design Stage


  1. Produce a System Specification

  2. Contain design components

  3. Include user interface, queries and reports

  4. Produce DFDs

  5. Produce Pseudocode

  6. Create test plan
• 3 activities in System design

  • Design of user interfaces
  • Design of queries + reports
  • Data validation + verification to be used
• Development Stage


  1. Develop the Software package

  2. Produce program code for each feature

  3. Develop data structures and user interfaces

  4. Implement the design specification
• Testing Stage


  • Ensure the system specification is followed and the system works as described
  • Identify and correct errors
  • Test plans give structure and ensure a range of data is used eg valid, boundary and invalid data
• Storyboarding


  • Includes user input and output options
  • Diagrams produced for each page of the website
  • Diagrams are non-linear and use branching to show different navigation paths
• Prototyping


  • Building a working model to give users a look and feel experience
  • Users can evaluate and provide feedback
  • Developer can adjust the prototype based on feedback
• Evolutionary prototyping


  The prototype becomes the full working model
• Throwaway prototyping


  The prototype is used to produce a set of requirements, then discarded and the system is developed using an alternative approach
• Quality Indications


  • Suitability
  • Usability
  • Effectiveness
• Suitability


  • Is the system fit for purpose?
  • Is it compatible with existing hardware and software?
  • Is it error free and robust?
• Usability


  • Is the user interface intuitive?
  • Does it have transferable skills from previous software?
• Effectiveness


  • Does the system meet all of its objectives?
  • Does the user interface perform all tasks efficiently?
• Main features of system testing


  • Carried out by the developer
  • Ensures the system works as described in the specification
  • Tests each individual system function with normal, extreme and individual data
  • Ensures the system produces correct results
• Main features of acceptance testing

  • Tested in the live environment with real volumes of data
  • Tested by the end user to ensure it meets all requirements
  • End user can provide feedback on any issues
• Main features of Alpha testing

  • Carried out by the development team
  • Includes module, integration, white box and system testing
  • Tested using the module specification
• Main features of Beta testing


  • Carried out by potential users in a realistic environment using real volumes of data
• Test plan


  • Produced at the design stage
  • Detailed document used by testers
  • Outlines elements to be tested and expected results
  • Records whether tests were successful or not
  • Allows system modification and retesting if actual results differ from expected
• Main components of a test plan

  • Item or module to be tested
  • Test data to be used
  • Expected outcome
  • Actual outcome
• Test case


  A set of data to test a particular scenario and the expected outcome
• Not all errors are identified and fixed during testing, some may be discovered later during maintenance