The document introduces unit testing to management and business stakeholders, explaining that unit tests are written by developers to test their code, catch errors early in the development process when they are cheaper to fix, and ensure code works as intended as well as provide many other benefits like establishing a safety net and writing cleaner code. Unit tests should be implemented throughout the software development lifecycle from initial coding through integration and regression testing.

1. Introduction of Unit Test to
Management and Business
August, 2012
Wei Li

2. ”To err is human;
to forgive, divine.”
Alexander Pope

3.  Developer Test
– Unit Test
– Integration Test
– Regression Test
 QA Test
– Integration Test
– Regression Test
– Performance Test
– Stress Test
 Customer/User Test
– Acceptability Test
– Usability Test
Many Tests in the Life Cycle of Software Development

4. What is Unit Test
 Self checking or validation to ensure the code work as expected
 Developer’s test
 Part of construction cycle
 Foundation of all other tests

5. Where Does Unit Test Fit in Life Cycle?
 Requirement gathering
 Business Design
 Technical Design
– Architecture Design
– Technical Design
 Construction
– Code and Unit Test
 QA Test
 Performance Test
 User Test

6. Unit Test Is Not
 QA test
 Customer/user test

7. Why?
 What? Write code to test code?
 No! I don’t have time for it!

8. Benefits of Unit Test – Instant Feedback
 Unit test provides the earliest opportunity to identify and fix a defect
 The earlier an error is found, the less expensive it is to fix it
 Performed before components are integrated together

9.  Force the developer to write clean and testable code – which leads
to less complexity and better design
 If your code is hard to be tested, how can it be easily used,
maintained and extended?
Benefits of Unit Test – Write Testable Code

10. Benefits of Unit Test – Establish Safety Net in the Lifecycle
 Can be used as part of regression test suite
 Provide the green light to refactor old code and make changes

11. Benefits of Unit Test – Good Way to Work with Legacy/Existing Code
 Write unit test to get started understanding legacy code and system

12. Benefits of Unit Test – Excellent Way to Learn New Language and API
 Write unit test cases to learn and try new API
 The unit test cases can become reusable knowledge base

13. Benefits of Unit Test – Excellent Way to Report a Defect
 Write a unit test case to report a defect or a bug in the system
 Run the same test to verify the defect is fixed

14. Benefits of Unit Test - Reusability
 Write once run forever – reusable and repeatable
 Save time long term in the life cycle
 Give new team member a good jump start

15. Unit Test Practice
 Planning and estimation - account for the construction time
for unit test
 Code a little and unit test a little - repeat the cycle until the
construction is done
 Part of the code review process
 Run unit test when trouble shooting issues
 Run unit test whenever a change is made
 Run unit test whenever is needed
 Enjoy the results

16.  Our old friend JUnit is still our best friend
– No new wheel was reinvented
– De facto tool
– Familiarity to most developers
Unit Test Practice

17.  Use a separate unit test project
– Only contain unit test related Java code but test code in other projects
– Run locally and not deployed to application server
 Won’t be part of the deployable to application server
– Freedom to write more unit tests
– Save time in testing (no build and deployment)
Unit Test Practice

18.  Unit test coverage – the thorough the better
Unit Test Practice

19.  Just do it and it will become a habit
 You will find out you actually have time to write unit test code
 You will find out you actually enjoy doing it
Unit Test Practice

20. Test Driven/Test First Methodology
 Write a test case for a new functionality
 Run the test and it fails
 Write just enough code to make the test pass
 Run the test and it passes
 Refactor the code to make it better
 Repeat the test
 Repeat the cycle

21. Continuous Integration
 Get the latest version of the code from source control system
 Build/compile the code
 Run all unit test cases
 Publish the build and test results
 Notify the development team for any failure
 Repeat the process periodically, for example, once every hour

22. ”To err is developer;
to catch early, unit
test.”