The Trend in Integration Test

The trend in Integration Test:

• traditional top-down or bottom-up approaches favour the developers
• the functional approach favours the testers
• the object-oriented approach naturally leads the developers into functional integration

Advantages and Disadvantages of Functional Integration

Advantage:

• Accomplishes system function

Disadvantages:

• May be hard to define data to test lower level module conditions
• May be hard to locate faults

What is Functional Integration?

Functional Integration:

• Start with a specific function
• Use incomplete components, stubs and drivers as needed to conduct testing
• Progress to multiple functions
• Functional cases may be usable for system testing

Disadvantages of Bottom-Up Integration

Disadvantages of Bottom-Up Integration includes:

• Cases may not be usable at the system level
• May be hard to detect interface faults
• major design faults will be detected late

Advantages of Bottom-Up Integration

Advantages of Bottom-Up Integration includes:

• Easy to locate faults
• Does not need stubs

What is Bottom-Up Integration?

Bottom-Up Integration is:

• Driver is built to quality software modules
• Modules are linked when a driver can be replaced by a new module and all modules called by the new module have been qualified

Disadvantages of Top-Down Integration

Disadvantages of Top-Down Integration includes:

• May be hard to define and input data to test lower level module conditions
• Lower level modules are not tested as frequently as upper level modules
• Functionality may be severely limited or smart stubs required

Advantages of Top-Down Integration

Advantages of Top-Down Integration includes:

• Accomplishes "working" system
• Easy to locate faults
• Does not need drivers

What is Top-Down Integration?

Top-Down Integration is:

• Start with control modules
• Add a few modules for each build
• Data injected from "qualified" modules
• Missing modules simulated with stubs

Supporting Software in Integration Test

Some supporting software in Integration Test include:

• Drivers
  Programs that invoke the software being tested and simulate the activity of higher level application components. They usually provide test input and report test result.
  
  
• Stubs
  Dummy program modules used to enable the testing of higher-level invoking components. Their functional capabilities range from none to extensive simulations of actual application modules.

Key Integration Issues in SDLC

What modules should be assembled and tested as a group?

• Functional subassemblies
• Top level grouping working down
• Bottom level groupings work up
• Crtical feature first

How much scaffolding cde or test support code is required?

How much testing is appropriate?

• Subassembly
• Interfaces only
• All invoking functions and features
• Stress and break conditions

How will problems be isolated?

Integration Test Criteria

Integration Test Criteria includes:

• Compliance with Sub-Assumbly Functional Requirements
• Assessment of Timing, Sizing and Accuracy
• Performance at Boundaries and Under Stress
• Measurement of Functional Test Coverage
• Measurement of Software Reliability

Objective of Integration Testing

The objective of Integration Test is to ensure that various system parts of related components and programs work properly together.

It includes:

• Integrates Components.
• Components with Components Tests
• Hardware Interfaces Tests
• External Software Interfaces Tests
• Functional Requirements Tests
• Sub-Assembly Tests