Unit Tests...

• verify the functionality of a specific section of code

• written by developers

• white-box style testing

• usually at the method level

• in OOP, usually at the class level

• automated tests as documentation

Unit Tests...

• find problems early
• easier refactoring

Unit Tests...

• like writing client for your code
• make you to look at the user's (other developer's or just yourself's) perspective

Unit Tests...

"A failure in a high-level test is not just a bug in functional code, it's also a missing unit test"

~Martin Fowler

Unit Tests & TDD

Test-Driven Development lifecycle

http://www.agilenutshell.com/test_driven_development

How to Practice on Unit Testing & TDD?

• Find test-less modules via SonarQube and write tests for them
• Read test codes written by others
• Pair Programming
• Use TDD Code Katas:
  • http://codekata.com/

Code Coverage...

is a measure used to describe the degree to which the source code of a program is executed when a particular test suite runs.

Metrics:

• Line coverage
• Method coverage
• Class coverage

Code Coverage...

"I get paid for code that works, not for tests, so my philosophy is to test as little as possible to reach a given level of confidence..."
~Kent Beck

Continuous Integration

In XP, CI was intended to be used in combination with automated unit tests written through the practices of test-driven development.

https://www.pagerduty.com/resources/learn/what-is-continuous-integration/

Unit Testing Libraries for Java

• JUnit
• Mockito
• Hamcrest
• Testing frameworks comes within application development frameworks, for example Spring Test Framework
• ...

Unit Testing Examples for Java

Contains various testing examples for Java projects:

https://github.com/ufuk/testing-example-collection-for-java

DEMO