This course is designed to bring about a fundamental change to the way developers go about their day-to-day business of writing software code. Instead of thinking about unit tests as at best an afterthought, having already written the application code, the course aims to turn this practice on its head, and get programmers to write tests before the code to be tested.
Originating in the Agile methodology of Extreme Programming, Test Driven Development (TDD) has become accepted as a mainstream best practice, and is being adopted by major organisations as means of improving code quality and developer productivity.
Because Test Driven Development involves such a major inversion of most developers' ways of thinking and working, the course is strongly exercise based - it is necessary to spend a large part of the two days of the workshop practicing test-first development.
Typically developers find TDD initially strange, but go on to find it quite liberating, and become 'test infected' (unable to write code without having first devised unit tests.)
The exercises are based on the Java programming language, and use the tools most central to TDD in Java, including Eclipse (students are free to use tools they are comfortable with), JUnit and some of its extensions, Hamcrest, mocking with jMock and developing system level TDD scripts using fitnesse.
Competence in Java, or similar object-oriented programming language.
At the end of this course you will have:
- The ability to take the TDD approach to software development
- An understanding of the key techniques and strategies of TDD, and principles of refactoring code
- The ability to write unit tests in JUnit versions 4 and 3
- The ability to use mock objects in unit tests
- Work with fitnesse to develop system level tests
- Track down bugs quickly using JUnit and fitnesse
Unit tests and the xUnit framework.
- JUnit overview
- The TestCase and Assert classes
- Developing a JUnit 4 test and test suite for a class
- Java 5 features used in JUnit 4
- JUnit 4 versions of tests and test suites
- JUnit and ant
Motivation for using Mock Objects.
- Stubs and Mocks
- Worked example
- EasyMock argument matchers
- Mocking and Static methods.
- When to use Mock Objects
- Drawbacks of Mock Objects
Test Driven Development.
- Test Driven Development
- Benefits of TDD
- TDD Strategies - with JUnit and with fitnesse
- TDD Process: Worked Examples with JUnit
- TDD Process: Worked Examples with fitnesse
- TDD Testing Best Practices
- Exception tests
- Performance tests
- Fixing broken code in a speedy manner, successfully tracking down bugs using a combination of unit tests and TDD scripts
- Benefits of Refactoring Code.
- Important Refactorings
- Testing Patterns
- Testing Heuristics
- Pros and Cons of TDD
The workshop is strongly oriented towards lab work. In order to reverse deeply ingrained habits, of writing code first and tests only as a possible afterthought, it is essential to give developers as much time as possible working in a test-first manner.