Requirements Engineering Processes and Techniques Authors: Gerald Kotonya and Ian Sommerville

1
Requirements Engineering Processes and Techniques
Authors Gerald Kotonya and Ian Sommerville

• Chapter Four - Requirements Validation
• SYST510

2
Requirements Analysis vs Requirements Validation

• Analysis concerned with
• raw informal requirements from incomplete system
• requirements meeting stakeholder needs
• Do we have the right requirements?
• Validation concerned with
• checking a final draft of the SRS
• Do we have requirements right?

3
Requirements Problems Discovered During Validation

• Lack of conformance to quality standards
• Poorly worded, ambiguous requirements
• Errors in system models
• Conflicts not detected during analysis

4
Requirements Validation Process

• Figure 4.1, page 89
• Inputs
• requirements document
• organizational standards
• organizational knowledge
• Outputs
• list of problems
• agreed actions

5
Requirements Reviews Process

• Figure 4.2, page 91
• Process steps
• Plan review
• Distribute documents
• Prepare for the review
• Hold review meeting
• Follow-up actions
• Revise document

6
Pre-review Checking Process

• Figure 4.3, page 93
• Accomplished by one person
• Process steps
• Check document completeness
• Check document against standards
• Run automatic checkers
• Create problem report

7
Validation Process

• Review team membership
• need different stakeholders from different
  backgrounds
• Review checklists
• Quality attributes, Figure 4.4, page 96
• Checklist questions, Figure 4.5, page 97

8
Requirements Problems Examples

• Library case study problems
• Individual requirements problems
• Figure 4.6, page 98
• Global requirements problems
• Figure 4.7, page 99

9
Prototypes in Requirements Validation

• To further develop the prototype developed during
  elicitation
• Choose prototype testers
• Develop test scenarios
• Execute scenarios
• Document problems
• Figure 4.8, page 101

10
Prototype User Manual Development

• User manual should contain
• Description of the functionality and how to
  access it through the user interface
• Identification of functionality not implemented
• Recovery procedures
• Installation instructions
• May be basis for final user manual

11
Model Validation

• System models may include
• Data Flow Diagrams
• Object models
• Event models
• Entity Relationship Diagrams, etc.

12
Model Validation

• Objectives
• Determine model is self-consistent
• All models of system are internally and
  externally consistent
• Demonstrate models accurately reflect requirements

13
Requirements Testing

• Each functional requirement should be analyzed
  and a test defined to check if the system
  satisfies the requirement
• Test case questions
• What usage scenario might be used?
• Is there enough information for the requirement
  to be tested alone?
• Is coverage possible with a single test?

14
Requirements Test Form

• Should contain
• requirements identifier
• related requirements
• test description
• requirements problems
• comments and recommendations
• Figure 4.11, page 108

15
Exercises

• Kotonya, page 110
• assigned in class