The Systems Life Cycle: Testing (Cambridge International IGCSE ICT)

What is the system life cycle?

• The system life cycle is a structured process that guides the planning, creation, testing, and **deployment **of an information system

• Ensures systems are** systematically developed**, meeting needs of stakeholders, minimising risks and maximising efficiency

• The third stage is testing, the purpose is to:

  • Verify that the system meets all requirements, functions correctly, and is free of bugs through various testing methods.

Test Strategies

What are test strategies?

• A test strategy is **a method of testing a completed system **to ensure all parts work as intended
• Systems are designed in a modular format
• Each module needs to be** tested independently**
• Testing is done again once all modules are joined together
• The results of testing may indicate changes need to be made, testing is repeated once all changes have been made

Test designs

Test plans

• A test plan is designed and implemented to ensure thorough testing of a system, it includes:

  • Test data: specific data used for testing purposes
  • Expected outcomes: predicted results based on test data
  • Actual outcomes: results obtained from testing
  • Remedial action: steps taken to fix identified issues

Test Data

What is test data?

• Test data is specific data used for testing purposes

• There are four main categories of test data that would be used whilst performing final testing on a system

  • Normal
  • Extreme
  • Abnormal
  • Live

Normal data

• Normal test data is data that should be accepted in the system
• Normal data has a known outcome

Extreme data

• Extreme data is data that is on the limits of what is acceptable

Abnormal data

• Abnormal data is data outside of the limits of what is acceptable
• Abnormal data should be rejected by the system

Live data

• Live data is data from the old system used on the new system
• Live data has known outcomes, so it can be compared to the new system to ensure the new system works

Worked Example The European Space Agency (ESA) is building a new space telescope to orbit the Earth and search for distant galaxies. The ESA is using computer controlled robots to build the lens of the telescope. A new computer system will operate the space telescope; the new computer system is made up of several modules.

Describe how the new computer system is to be tested before it is fully operational.

[4]

Answer

four of:

Final answer: Each module has to be tested independently to ensure it functions correctly [1] Modules need to be tested together [1] Data needs to be transferred from module to module to check for data clashes [1] Errors need to be noted and corrections made [1] Then tested again [1] The system as a whole needs to be fully tested under controlled conditions [1]