This document discusses testing off-the-shelf (COTS) components. It defines COTS components as independently developed and reusable parts that are selected from a repository and assembled to build software systems. While COTS components reduce development costs and time, they present challenges to testing due to being treated as black boxes without access to requirements or development processes. The document outlines types of COTS component testing, including black-box testing of inputs/outputs, fault injection to evaluate error handling, operational testing in integrated systems, and interface propagation analysis to observe impacts of faults between components.

1. Testing off the shelf Components
Dr. Himanshu Hora
SRMS College of Engineering & Technology
Bareilly (INDIA)

2. Outline :
 Introduction to COTS components
 Advantages of COTS components
 Challenges in testing COTS components
 Testing types of COTS components
 References

3. Introduction:
What is Component Based Software Engineering (CBSE)?
 Idea to develop software systems by selecting appropriate
off-the-shelf components and then assemble them with a
well-defined software architecture.
 CBSE has three major functions:
Developing software from prefabricated, reusable
parts.
The ability to use those parts in other applications.
Easily maintaining and customizing those parts to
produce new functions and features.

4. What is a COTS component:
What is a Commercial Off the shelf (COTS) component:
 Independent and replaceable part of a system that fulfills a
clear function
 Works in the context of a well defined architecture
 A component communicates with other components by its
interfaces
 Developed by different developers, using different
languages and different platforms

5. Contd….
Component 1
Component
repository
select
Component 2
Software system
Component n
assemble

6. Advantages of COTS:
Development cost is reduced
Development time is reduced
Complex systems can be built by reusing pre-existing
components
Testing effort is reduced

7. Testing Components: Challenges
 COTS is a Black Box
 Lack of Functional and Technical Requirements
 The Level of Quality is Unknown
 Unknown Development Processes and Methods
 Compatibility Issues
 Uncertain Upgrade Schedules and Quality
 Difficulty in Regression Testing and Test Automation
 Interoperability and Integration Issues

8. Testing techniques:
 Black-box component testing
 System-level fault injection
 Operational system testing
 Software Wrapping
 Interface propagation Analysis

9. Black box Testing:
 To understand the behavior of a component, various
inputs are executed and outputs are analyzed
 To catch all types of errors all possible combinations of
input values should be executed
 To make testing feasible, test cases are selected
randomly from test case space

10. Contd….

11. Fault Injection:
request
Fault
simulation
tool
Erroneous or
malicious input
Component
Fault
simulation
tool
Exceptions, No
response

12. Contd….
 A technique for improving the coverage of a test by
introducing faults to test code paths
 Fault propagate through to an observable failure follows
a well defined cycle
 When executed, a fault may cause an error, which is an
invalid state within a system boundary
 An error may cause further errors within the system
boundary
 Each new error acts as a fault
 When error states are observed at the system boundary
they are termed failures
 This is termed the fault-error-failure cycle

13. Contd….

16. Operational system testing:
 complements system-level fault injection
 System is operated with random inputs (valid and invalid
inputs)
 Provides more accurate assessment of COTS quality
 A key operational testing feature is error detection,
which ensures correct functional implementation
 Operational testing allows component interaction

17. Software Wrapping :
Input wrapper
Input
Output wrapper
Component
output

18. Contd….
 Wrapper: generally refers to a type of packaging, such as
a flat sheet to enclose an object
 It is a piece of code that one builds to isolate the
underlying components from other components of the
system
 Glue: A glue component provides the functionality to
combine different components

19. Interface propagation Analysis:
COTS
Component 1
Fault Injector
 Modify input, call correct method.
 Call correct method, modify output.
COTS
Component 2

20. Contd….
 Interface Propagation Analysis is used by injecting faults
at one component
 This is done at component integration level
 A known faulty input is injected using fault injector into
the system
 Components effected by this input are observed (how
they handle the faulty input)

21. Refrences:
 http://www.cigital.com/presentations/zurich98/sld087.h
tm
 http://my.safaribooksonline.com/book/softwareengineering-and-development/softwaretesting/0201325640/testing-interactions/ch06lev1sec4
 http://my.safaribooksonline.com/book/softwareengineering-and-development/softwaretesting/0201325640/testing-interactions/ch06lev1sec4

22. Thank You
Dr. Himanshu Hora
SRMS College of Engineering & Technology
Bareilly (INDIA)